Journal articles: 'Cr [chrome]'

1

LEWIS, D. M., and G. YAN. "Chrome dyeing using Cr(n1) salts." Journal of the Society of Dyers and Colourists 110, no. 8 (September 1994): 281. http://dx.doi.org/10.1111/j.1478-4408.1994.tb01659.x.

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Yu, Yue, Yunhang Zeng, Tao Liang, Jianfei Zhou, and Bi Shi. "Inverse Chrome Tanning Technology." Journal of the American Leather Chemists Association 115, no. 5 (May 1, 2020): 176–82. http://dx.doi.org/10.34314/jalca.v115i5.3811.

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Conventional chrome tanning technology (CCTT) generates a remarkable quantity of Cr(III)-containing wastewater and solid wastes, which may pose a potential risk to the environment. In this work, an inverse chrome tanning technology (ICTT) was developed based on chrome-free tanning by Al–Zr complexes and highly oxidized starch (AZ–HOS) to minimize Cr(III) discharge. The 7.5% AZ–HOS exhibited sufficient tanning effect and gave wet white a shrinkage temperature of over 80o C. Thus, wet white can be stably stored for one year and possessed high absorption capacity to post-tanning chemicals (85%–90%) because its pI (7.1) was as high as that of wet blue. Terminal chrome tanning with 1.0% chrome tanning agent after post-tanning gave the ICTT crust leather physical and organoleptic properties that are comparable to those of CCTT crust leather. Moreover, the Cr and TOC loads in ICTT wastewater decreased by 99.9% and 42.4%, respectively. Therefore, this work provides a clean and practical tanning system for the sustainable leather industry.

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Yasril, Yasril, Heru Subaris Kasjono, and Sri Puji Ganefati. "PENURUNAN KADAR KROM (Cr) DENGAN MENGGUNAKAN BIOMASA AMPAS TEBU SECARA BIO-ADSORBSI." Jurnal Teknologi Lingkungan 10, no. 2 (December 14, 2016): 145. http://dx.doi.org/10.29122/jtl.v10i2.1486.

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Chrome is a substance belong to high toxicity heavy metal group which can causeboth acute and chronic poisoning. One of the methods that can be used to reduceits concentration is biosorbtion with bagasse biomass. The objectives of the studywere to understand the chrome concentration before and after absorbed, as wellas to understand the amount of the most effective biomass.The study was an experimental with three treatments of which consisted of eightrepetitions. The sample was synthetic liquid waste and the treatment absorbentwas bagasse biomass which was processed as activated carbon of 10, 15, and 20grams weight. The chrome concentration were measured by using AAS method.The results showed that the chrome concentration before treated was 10,196mg/l, and the average of the reduction from the three absorbents weight were:0.174 mg/l, 0,099 mg/l, and 0,011 mg/l respectively.It can be concluded that there were reduction differences amongst the threetreatments, and 20 gr absorbent was the most effective one (99.88 % reduction).It is advised for further study to apply the bagasse for processing liquid waste fromindustrial activities.

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Mahmoud, Ahmed S., Nouran Y. Mohamed, Mohamed K. Mostafa, and Mohamed S. Mahmoud. "Effective Chromium Adsorption From Aqueous Solutions and Tannery Wastewater Using Bimetallic Fe/Cu Nanoparticles: Response Surface Methodology and Artificial Neural Network." Air, Soil and Water Research 14 (January 2021): 117862212110281. http://dx.doi.org/10.1177/11786221211028162.

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Tannery industrial effluent is one of the most difficult wastewater types since it contains a huge concentration of organic, oil, and chrome (Cr). This study successfully prepared and applied bimetallic Fe/Cu nanoparticles (Fe/Cu NPs) for chrome removal. In the beginning, the Fe/Cu NPs was equilibrated by pure aqueous chrome solution at different operating conditions (lab scale), then the nanomaterial was applied in semi full scale. The operating conditions indicated that Fe/Cu NPs was able to adsorb 68% and 33% of Cr for initial concentrations of 1 and 9 mg/L, respectively. The removal occurred at pH 3 using 0.6 g/L Fe/Cu dose, stirring rate 200 r/min, contact time 20 min, and constant temperature 20 ± 2ºC. Adsorption isotherm proved that the Khan model is the most appropriate model for Cr removal using Fe/Cu NPs with the minimum error sum of 0.199. According to khan, the maximum uptakes was 20.5 mg/g Cr. Kinetic results proved that Pseudo Second Order mechanism with the least possible error of 0.098 indicated that the adsorption mechanism is chemisorption. Response surface methodology (RSM) equation was developed with a significant p-value = 0 to label the relations between Cr removal and different experimental parameters. Artificial neural networks (ANNs) were performed with a structure of 5-4-1 and the achieved results indicated that the effect of the dose is the most dominated variable for Cr removal. Application of Fe/Cu NPs in real tannery wastewater showed its ability to degrade and disinfect organic and biological contaminants in addition to chrome adsorption. The reduction in chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solids (TSS), total phosphorus (TP), total nitrogen (TN), Cr, hydrogen sulfide (H2S), and oil reached 61.5%, 49.5%, 44.8%, 100%, 38.9%, 96.3%, 88.7%, and 29.4%, respectively.

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Chalupová, Adéla, Martin Steinbrück, Mirco Grosse, Jakub Krejčí, and Martin Ševeček. "HIGH-TEMPERATURE OXIDATION OF CHROME-NICKEL ALLOY." Acta Polytechnica CTU Proceedings 28 (December 1, 2020): 8–14. http://dx.doi.org/10.14311/app.2020.28.0008.

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The investigations in this paper deal with the Cr-Ni alloy. The material has been recently proposed as a potential ATF concept, primarily due to its behaviour under high-temperature oxidation. A set of experiments to determine the melting point and describe the oxidation kinetics of the Cr-Ni alloy were performed in Karlsruhe Institute of Technology. Presented results reveal its superb oxidation resistance comparing to zirconium alloys. Therefore, the alloy has a great potential for nuclear applications.

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Uddin, Md Minhaz, Jawad Hasan, Md Didarul Islam, Ashiqur Rahaman, and Sayed Md Shamsuddin. "Removal of Chromium(III) and Other Physical Parameters from Chrome Tan Wastewater and Recovery of Chromium from the Precipitating Sludge." Textile & leather review 3, no. 2 (June 16, 2020): 64–77. http://dx.doi.org/10.31881/tlr.2020.07.

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This study was adopted to investigate the removal of Cr(III)and other physicochemical parameters of chrome tan wastewater. For this purpose, three precipitating agents, CaCO3, NaHCO3, and MgO, were used to treat chrome tan wastewater. After treatment, it was found, in three different dose trials, that each agent removed almost 97-99.5 % of chromium. At the same time, it was observed that with the increase of doses, removal percentage of TDS, conductivity, and turbidity of effluent were reduced. In the case of NaHCO3 and CaCO3, Cr(III) removal percentage at optimum pH was found to be 99.97% and 99.95% respectively, whereas the maximum removal percentage for MgO was found to be 99.98%. The NaHCO3 and CaCO3 were found to be comparable to MgO for Cr(III) removal from chrome tan wastewater. The recovered chromium concentration in the sludge for NaHCO3 and CaCO3 were also similar to that of MgO. This research suggests that these two precipitating agents can be used in the same way as MgO, for Cr removal and recovery treatments. Moreover, this recovered chromium can be reused, thus reducing the environmental pollution.

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Yu, Hui Cheng, Fu Hou Lei, Guang Hui Deng, and Xue Cai Tan. "Investigation of Anticorrosive Trivalent-Chrome Coatings on 6063 Aluminum Alloy." Advanced Materials Research 396-398 (November 2011): 1764–68. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.1764.

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In this work, Chromium (Cr(III)) conversion coatings on Al 6063 alloy was prepared using trivalent-chrome compound (KCr(SO4)2) and H3PO4. The influence of five variables (i.e. deposition temperature, time, bath pH, and concentrations of (Cr(III)) compound (KCr(SO4)2) and H3PO4) on the preparation of (Cr(III)) coating on Al 6063 alloy was investigated using polarization curve in 3.5 wt% NaCl solution. The parameters of polarization curves were obtained from the extrapolation of anodic and cathodic Tafel lines. The optimum chemical passivation parameters of the chromium (Cr((III)) conversion coatings on the 6063 Al surface were obtained in this paper The results show the chromium (Cr(III)) conversion coatings formed under the optimal range present better corrosion resistance than those under the other conditions. Proper mechanisms were proposed to explain the above electrochemical behavior for the five treated conditions.

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8

Avena, Marcelo J., Carla E. Giacomelli, and Carlos P. De Pauli. "Formation of Cr(III) Hydroxides from Chrome Alum Solutions." Journal of Colloid and Interface Science 180, no. 2 (June 1996): 428–35. http://dx.doi.org/10.1006/jcis.1996.0322.

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9

Mutto, Juan Cruz, Tabata Prado Sato, João Mauricio Ferraz Da Silva, Alexandre Luiz Souto Borges, and Eduardo Shigueyuki Uemura. "Retentiveness comparison of individual clasps made from polyamide, acetate resin and cobalt-chrome for removable partial dentures." Brazilian Dental Science 22, no. 4 (October 31, 2019): 483–87. http://dx.doi.org/10.14295/bds.2019.v22i4.1802.

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Objective: This study aimed to evaluate and compare the retention force of individual clasps made from polyamide, acetate resin and cobalt-chrome for removable partial dentures. Material and methods: Three groups of clasps were fabricated: Cr-Co - 10 conventional chrome-cobalt metal clasps; Ac - 10 clasps with reciprocal arms and occlusal rests in chrome-cobalt and retentive arms in acetate resin; and Poly - 10 clasps with reciprocal arms and occlusal rests in chrome-cobalt and retentive arms in polyamide resin. Through the tensile test, in a universal testing machine, the initial retention force of the specimens was obtained and then clasps were cycled 7200 times, immersed in artificial saliva (60 months of simulated clinical use). After cycling, tensile test was performed. Results: All groups presented a retention decrease after the cycling. Ac presented a large reduction in retentive force (61.43%), followed by Cr-Co (26.5%) and Poly (12.09%). Conclusions: Aesthetic clasps of polyamide can be used in clinical cases where the anterior supporting teeth will not be essential for good retention of the removable partial denture because this clasp showed to be more resistant than the acetate resin.

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10

Samoilova, O. V., and Evgeny A. Trofimov. "Phase Equilibria in the Copper-Rich Corner of the Cu-Ni-Si-Cr System." Materials Science Forum 870 (September 2016): 107–12. http://dx.doi.org/10.4028/www.scientific.net/msf.870.107.

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Thermodynamic modeling of phase equilibria in the copper-rich corner of the Cu–Ni–Si–Cr system is performed. The "FactSage" software was used for thermodynamic modeling. Isothermal sections of the Cu–Ni–Si–Cr phase diagram with phase existence areas depending on the concentrations of nickel, silicon and chrome are plotted. Reactions between nickel, silicon and chrome, dissolved in a copper melt, are studied experimentally. The samples after crystallization are investigated using scanning electron microscope and X-ray phase analysis. The conditions of silicide formation in as-cast condition are defined. The research results can be used for technology analysis in copper and copper-based alloys production.

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11

Zerhouni, R. A., D. Bouya, C. Ronneau, and J. Cara. "Étude de l'absorption des phosphates, azote, chrome et cadmium par trois algues vertes isolées à partir d'effluents urbains." Revue des sciences de l'eau 17, no. 3 (April 12, 2005): 317–28. http://dx.doi.org/10.7202/705536ar.

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La capacité de déphosphatation et de dénitrification ainsi que la sensibilité et l'accumulation de deux métaux lourds (Cr et Cd) de Scenedesmus quadricauda, Chlorella pyrenoidosa et Chlamydomonas reinhardtii isolées des eaux usées de la ville de Fès, ont été étudiées dans les conditions de laboratoire. Les résultats ont montré que S. quadricauda présente les meilleurs taux de réduction des phosphates (83%), et d'ammonium (75%). L'étude de la sensibilité vis à vis du chrome et du cadmium des trois espèces, a montré qu'au delà d'une concentration de 1 ppm, la croissance se trouve réduite et que S. quadricauda présente une sensibilité plus faible que les deux autres espèces. Les résultats des expériences d'absorption conduites avec du chrome VI marqué au51 Cr et du cadmium marqué au109 Cd ont montré que les quantités de chrome et du cadmium prélevées par S. quadricauda dépassent celles des deux autres espèces. L'utilisation potentielle des trois espèces dans le traitement des effluents urbains est discutée à la lumière des résultats de ces expériences.

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12

Widiyati, Cahya, and Herry Poernomo. "STABILIZATION OF DRY SLUDGE OF LIQUID WASTE OF LEATHER TREATMENT BY USING FLY ASH." Indonesian Journal of Chemistry 5, no. 1 (June 14, 2010): 36–40. http://dx.doi.org/10.22146/ijc.21836.

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The experiment of solidification of dry sludge of liquid waste of leather treatment are containing chrome (Cr) by using fly ash has been done. The experiment objective are immobilize Cr in the solid waste by using pozzoland cement was made of fly ash in order to stable in the repository. The experiment were carried out by solidification of solid waste are containing total chrome of 1480.5 mg/kg sum of 2 - 10 weight % of (water + pozzoland cement) by using pozzoland cement was made from the mixture of fly ash and calcite were burned at 1000 oC temperature for 2 hours. The characterization of the solid composite of stabilization result consist of the compressive strength test and the leaching test by American Nuclear Society (ANS-16.1) method. The experiment result were shown that pozzoland cement can binding solid waste sum of 10 weight % of (water + pozzoland cement) became the composite of waste concrete with the compressive strength of 577 ton/m2 and the chrome leaching test for 14 days of 0.059 mg/l. The composite of waste concrete according to Bapedal rule for solidification of toxic waste with minimum compressive strength of 10 ton/m2 and maximum leached chrome of 5 mg/L. Keywords: stabilization, solid waste, leather treatment, fly ash.

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13

Pownceby, M. "Compositional and textural variation in detrital chrome-spinels from the Murray Basin, southeastern Australia." Mineralogical Magazine 69, no. 2 (April 2005): 191–204. http://dx.doi.org/10.1180/0026461056920246.

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AbstractDetrital chrome-spinels are contaminant grains within heavy-mineral concentrates found in the Murray Basin of southeastern Australia. The presence of even minor levels of chromia in the predominantly ilmenite-rich concentrates downgrades their market value as potential feedstocks for the production of titania pigment.Compositions from a database of close to 5000 chrome-spinel analyses show a broad range in chemistry. The major element components and their ranges (wt.%) are Cr: 3.10–52.06, Al: 0.46–32.50, Fe: 3.50–44.48 and Mg: 0.03–15.79. Minor components include; Ti: 0.01–6.41, Zn: 0.00–23.00 and Mn: 0.00–5.82. The broad variation in composition suggests multiple source areas for the chrome-spinels although detailed textural examination indicates that variation has also been introduced through pre- and post-deposition alteration processes.The Murray Basin chrome-spinel database has the potential to be used in interpreting and predicting the effects of various processing conditions used to separate the chrome-spinels from the ilmenite.

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Song, Jung Han, and Hoon Huh. "Dynamic Characteristics of the Sinter-Forged Cu-Cr Alloys with the Variation of Chrome Content." Solid State Phenomena 116-117 (October 2006): 255–58. http://dx.doi.org/10.4028/www.scientific.net/ssp.116-117.255.

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This paper is concerned with the dynamic characteristics of sinter-forged Cu–Cr alloy for various strain-rates. The amount of the chrome content is varied from 10 %wt to 30 %wt in order to investigate the influence of the chrome content on the dynamic characteristics. The dynamic response at the corresponding level of strain-rate should be obtained with an adequate experimental technique and corresponding apparatus due to the inertia effect and the stress wave propagation. In this paper, the high speed tensile testing machine is utilized in order to identify the dynamic response of the Cu–Cr alloy at the intermediate strain-rates and the split Hopkinson pressure bar is used at the high strain-rates. Experimental results from both the quasi-static and the high strain-rates up to the 5000/s are interpolated with respect to the amount of the chrome content in order to construct the Johnson–Cook and the modified Johnson–Cook model as the constitutive relation for numerical simulation of the dynamic impact behavior of electrodes.

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Zhang, Hongyan, and Jinhua Wang. "Research on preparation of chrome tin purple red pigment by using eggshell." Journal of Mines, Metals and Fuels 69, no. 4 (May 13, 2021): 127. http://dx.doi.org/10.18311/jmmf/2021/27800.

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The solid-phase synthesis of Cr-Ca-Sn-Si purple red pigment, the preparation of chrome tin pink stains are studied by using eggshell, which is used as the raw materials introducing the calcium carbonate. Through the experiment of formula is optimized, and by controlling the calcinations temperature and mineralizer measures a series of Cr-Ca-Sn- Si purple red pigments are prepared. The results showed that Cr-Ca-Sn-Si purple red pigments are prepared by using eggshell.

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Li, Yang, Yong Li, Rui Li, and Dong Wang. "Research on Cr₂O₃-Reinforcement High Quality Magnesia-Chrome Brick." Advanced Materials Research 233-235 (May 2011): 2565–70. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.2565.

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The raw material is the fused grain magnesia-chrome and Indian concentrated chrome ore . The grain size proportion which is used in the preparation as follows: 4-1mm 50%，≤1mm 17%,≤0.088mm 33% ,the 5 group samples are prepared by respectively adding extra 2%、4%、6%、8% fine power Cr2O3 to basic formula .Mixing and pressed under 200Mp and sintered at 1750,holding 8 hours ,the process of preparation of samples is finished .The dimension of samples is 230mm×114mm×65mm .Conclusion: the addition of fine power Cr2O3 can change the base material composition of magnesia-chrome ,form more secondry spinel and intergranular spinel ,promote direct bond between periclase and spinel .Adding quantitative fine power Cr2O3 can enhance the room properties and high temperature properties ,but as the increase of fine power Cr2O3 ,the sintering property is decreased ,the results are shown that the best content of fine power Cr2O3 should remain at about 4% .

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17

Vinokurov, Evgeniy G. "INTERNAL STRESS OF CHROME COATINGS ELECTRODEPOSITED FROM SOLUTIONS OF CHROMIUM (III) SALTS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 12 (December 7, 2019): 33–38. http://dx.doi.org/10.6060/ivkkt.20196212.6076.

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Experimental data on internal stress in chromium coatings electrodeposited from Cr(III)-solutions have been obtained. Tensile stress 250-300 MPa is observed in thin coatings with thickness was below 1-3 μm. The internal stress is practically independent on current density and pH of the solution. A reduction in the plate thickness corresponding to σ=0 is observed, when pH has changed from 1.2 to 1.6 and current density from 30 to 35 A/dm2 at higher values of pH and current density compressive stress is observed and increases the difference in the stress values at greater thicknesses of the coatings: ((– 10) - (– 50) MPa). These results have been compared with similar data for the coatings deposited from Cr(VI) solutions including the effects of the non-metal inclusions in the coatings (for Cr(III)-bath H – 10.5 - 13 at. % (26 - 32 ml H2 / g Cr), O – 0.06-0.6 at. %, С – 0.04-7.8 at. %; for Cr(VI)-bath H – 1.8 at. %, O – 1.2 at. %, С – 0 at. %)). Compressive stress, related with the inclusions (including carbides) is the major cause, limiting the possibility to improve the characteristics of chromium coatings and to deposit coatings of the quality comparable to that of chrome plated from Cr(VI) baths.

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18

Xing, J., and M. T. Pailthorpe. "Chrome dyeing of cashmere with SCA-Cr as the mordant." Coloration Technology 116, no. 3 (March 2000): 91–93. http://dx.doi.org/10.1111/j.1478-4408.2000.tb00026.x.

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Lestari, Sri, Ratna Stia Dewi, Eko Setio Wibowo, and Atang `. "Biosorption chrome (Cr) and dyes using biosorbent in the modified tea bag." Journal of Microbial Systematics and Biotechnology 1, no. 1 (June 24, 2019): 38–43. http://dx.doi.org/10.37604/jmsb.v1i1.20.

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Biosorption has been known as a potential method in reducing heavy metals and dyes in wastewater, including chrome (Cr) and dyes contents of the wastewater from the batik industry. Straw and spent mushroom compost (SMC) are potential biosorbents due to cheap, abundant, and easily obtained. However, the effectivity of the biosorbents is not only depended upon the type of material but also their surface area. In this study, a modified tea bag was used to increase the surface area of the straw and spent mushroom compost to absorb Cr and dyes from the batik industry wastewater. The optimum of biosorbent ratio and pH in Cr absorption and dyes decolorization was measured. This experiment was conducted using Spilt Plot Design. The results showed that the highest Cr absorption was found at 0,0050 mg/g, and the percentage of decolorization was 68,92% in the biosorbent ratio of 3:1 and pH 5. Biosorbent packed in the tea bags modification was effective removes Cr and dyes in the batik industry wastewater.

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Puspitasari, P., A. Yudhistantra, A. S. Haryono, J. W. Dika, M. Achyarsyah, and S. M. S. N. Shikh Zahari. "Hardness and microstructure investigation of steel rod ST 42 coated by chrome steel using wire arc spray coating." Journal of Achievements in Materials and Manufacturing Engineering 2, no. 90 (October 1, 2018): 69–76. http://dx.doi.org/10.5604/01.3001.0012.8385.

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Purpose: This research aimed to examine the hardness, surface roughness and microstucture in the Steel Rod ST 42 coated by chrome steel using wire arc spray coating with variations in spraying current of 140, 155, 170 and 180 Ampere. Design/methodology/approach: There was 12 specimens consisting of 3 specimens for each variation of the electric current coating. The specimens were cut to 30 mm in length and 27 mm in diameter; as many as 4 x 3 pieces, each specimen was cut to a size of 30 mm and put on a lathe to be drilled 1 mm deep. The hardness testing employed the Brinell hardness test method. The hardness testing process was followed by microstructure observation and SEM-EDAX testing. Findings: The highest hardness was 110.77 HRB by coated at 155 A and it contained many reinforcing inclusions and larger Cr. The lowest current of 140 A had many porosity holes and partially-melted particles, causing Cr grains did not attach perfectly. The current with 170 A had few inclusions and hence a decrease in hardness and at 180 A consisted of a low carbon content and evenly distributed inclusions and Cr and relatively large grain size, and thus the hardness rose. Research limitations/implications: The material of steel rod ST 42 coated by chrome steel. Practical implications: The variation of current should be prepared wisely in term because it will effect the hardness, surface roughness and microstucture. This research can be improved by varying the voltage, gas pressure, particle velocity, particle temperature, and molten wire width. Originality/value: Simple route of making steel rod ST 42 coated by chrome steel using wire arc spray coating and also the investigation of hardness, surface roughness and microstucture in steel rod ST 42 coated by chrome as the result.

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Peng, Chao, and Wei Bo Yang. "Effect of ZrO₂ Additive on the Properties of MgO-Cr₂O₃ Refractory Used for RH Degasser." Key Engineering Materials 680 (February 2016): 331–34. http://dx.doi.org/10.4028/www.scientific.net/kem.680.331.

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To improve the properties and RH degasser slag corrosion resistance of magnesia-chrome refractory, the effect of the addition of ZrO2 was investigated. The results showed that the presence ZrO2 additive can densify the magnesia-chrome samples due to promotion of grain boundary activities and ultimately direct bond formation, which improved the high temperature mechanical properties and corrosion resistance. The results also indicated that in the RH degasser slag system with a high ratio of calcia to silica, the slag resistance behavior of magnesia-chrome composite added ZrO2 could be described as follows: the ZrO2 reacts with CaO to form the calcium zirconate compound which is densification lay and simultaneously, could increase corrosion resistance performance by blinding pore and thickening slag viscosity. Therefore, it is expected to be the major reason for the ZrO2 enhanced corrosion resistance behavior observed for magnesia-chrome refractory.

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Votava, Jiří, Martin Kotus, and Vojtěch Kumbár. "Passivation of Zinc Coatings by Inhibition Chrome-Based Systems." Advanced Materials Research 1059 (December 2014): 67–73. http://dx.doi.org/10.4028/www.scientific.net/amr.1059.67.

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The anticorrosion resistance of metal (inorganic) coatings is defined by the system of anode and cathode protection. As zinc coatings do not load the environment in such an extent like organic paint systems, current trend is to maximally prolong the service life of a zinc coating. This paper is focused on analysis of the speed of corrosion degradation of zinc coatings. The individual samples were prepared by the method of hot-dipping and galvanizing. Inhibition systems were applied only to electrolyte-applied zinc coating. There were prepared three different passivating methods: (1) slim-layer passivation with the content of Cr (III), (2) slim-layer passivation with the inhibitor Cr (VI) and (3) thick-layer passivation with Cr (III). The thickness of anticorrosion coatings has been measured by both destructive and non-destructive methods. The weight of the applied anticorrosion substrate was measured in compliance with the ČSN EN ISO 3892 standard. Ductile characteristics were analysed according to the ČSN EN ISO 1519 standard. The total evaluation of anticorrosion resistance was processed according to the ČSN EN ISO 9227 standard (salt-spray test). Based on the results of corrosion tests, the individual coatings can be analysed and their corrosion resistance can be evaluated. The service life of the zinc coating can be prolonged by sealing off the zinc coating by an appropriate inhibitor which supports the self-healing effect of the whole anticorrosion substrate.

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Hussein, Samar S., Basim O. Hasan, and Naseer A. Al-Haboubi. "Galvanic Corrosion of Copper / Nickel-Chrome Alloy in an Agitated Sulfuric Acid Solution." Al-Nahrain Journal for Engineering Sciences 21, no. 1 (February 10, 2018): 133. http://dx.doi.org/10.29194/njes21010133.

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Galvanic corrosion of Nickel-Chrome alloy (Ni-Cr alloy) and Copper (Cu) coupled in 5% sulfuric acid solution was investigated. The effects of agitation velocity, temperature, and time on the galvanic corrosion current and the weight loss of both metals in both free corrosion and galvanic corrosion were investigated. The trends of open circuit potential (OCP) of each metal and galvanic potential (Eg) of the couple were also determined. The results showed that Cu was cathodic relative to Ni-Cr alloy in galvanic couple and the corrosion potential of the couple (Ni- Cr alloy /Cu) was between the values of the two single components because the OCP of copper shifted to positive with the increase in velocity. Under stagnant conditions initially the galvanic current was more negative then shifted to the positive with time. The corrosion of Ni-Cr alloy decreased with time because the passivation layer was formed on the surface. Under flow conditions, the galvanic current sharply shifted to the negative direction (increase galvanic current from Ni-Cr alloy (anode) to Cu (cathode) during the first few minutes.

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Prates, Raquel Cheyne, Heloisa Helena Capuano de Rezende, Ângela Maria Quintão Lana, Iran Borges, Patricia Carneiro Bernardes Moss, Raquel Silva de Moura, and Adalgiza Souza Carneiro de Rezende. "Heart rate of Mangalarga Marchador mares under marcha test and supplemented with chrome." Revista Brasileira de Zootecnia 38, no. 5 (May 2009): 916–22. http://dx.doi.org/10.1590/s1516-35982009000500019.

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The objective of this experiment was to characterize the heart rate (HR) of twelve Mangalarga Marchador mares, before, during, and immediately after 5, 10, 15 and 20 minutes of marcha tests, evaluating the effect of chrome on cardiac performance. The mares were assigned into three groups distinguished by supplementation of 0, 5 and 10 mg of Cr, respectively. The experiment was conducted in two phases, 24 and 6 days, respectively. The first phase included diet, Cr and exercise adaptation and the second, three 50-minute marcha tests, every other day. Before the tests, a Heart Rate Monitor was adapted to check the HR. The assay was randomly conducted in split-splot arrangement, with four replications. Mean comparisons were performed through minimal significative difference (MSD) test and the time evaluation was performed through regression adjustment model. The results showed positive effect of Cr on heart rate performance and animal return. Chrome did not influence the heart rate during the marcha tests and the HR values characterized the marcha tests as sub maximal intensity exercise.

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Ganbold, Boldbayar, Seong-Joo Heo, Jai-Young Koak, Seong-Kyun Kim, and Jaejin Cho. "Human Stem Cell Responses and Surface Characteristics of 3D Printing Co-Cr Dental Material." Materials 12, no. 20 (October 18, 2019): 3419. http://dx.doi.org/10.3390/ma12203419.

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Recently, the selective laser melting (SLM) method of manufacturing three dimensional (3D) dental prosthetics by applying a laser to metal powder has been widely used in the field of dentistry. This study investigated human adipose derived stem cell (hADSC) behavior on a 3D printed cobalt-chrome (Co-Cr) alloy and its surface characteristics and compared them those of a nickel-chrome (Ni-Cr) alloy. Alloys were divided into four groups according to the material and manufacturing methods. Co-Cr disks were manufactured with three different methods: a conventional casting method, a metal milling method, and an SLM method. Ni-Cr disks were manufactured with a conventional casting method. The surface roughness and compositions of the disks were assessed. hADSCs were then cultured on the disks. Cell morphologies on the disks were analyzed by a field emission scanning electron microscope (FE-SEM). Cell proliferation was assessed with a bromodeoxyuridine (BrdU) assay kit. Cell viability was evaluated with a water-soluble tetrazolium salt (WST) assay kit. There were no differences in surface roughness between all groups. The cells were well attached to the disks, and morphologies of the cells were similar. The cell proliferation and viability of the Ni-Cr disks were significantly lower than the other groups. However, the Co-Cr disks showed no differences in their different fabricating methods. In conclusion, the biocompatibility of 3D printed Co-Cr alloys showed comparable results compared to that of the conventional casting method, and these alloys were more biocompatible than Ni-Cr alloys.

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Onishchenko, S. A., and A. A. Soboleva. "Apoultramafic metasomatites of the Enganepe Uplift (the Polar Urals)." Vestnik of Geosciences 3 (2021): 11–20. http://dx.doi.org/10.19110/geov.2021.3.2.

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Ultramafic rocks of the Enganepe Uplift are transformed into serpentinites, magnesite-dolomite-talc and quartz-magnesite-dolomite metasomatites belonging to the beresite-listvenite formation. All apoultramafic rocks contain high chromium and nickel inherent in protolith. Chrome-spinel of the magmatic stage is represented by alumochromite, which, in the process of metamorphic and metasomatic transformation of rocks, has been replaced by secondary chrome-spinel (subferrialumochromite, ferrichromite) and chromium-bearing magnetite. The main nickel minerals are millerite and gersdorffite. In quartz-magnesite-dolomite rocks, nickel is party contained in Ni-Cr-chlorite.

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Montmitonnet, Pierre, Nassim Bouadjadja, Linh Phuong Luong, Jean Jacques Bertrandie, and Hervé Dietsch. "On the Mechanism by which Chromium Improves Strip Surface Cleanliness in Steel Strip Cold Rolling." Key Engineering Materials 767 (April 2018): 240–47. http://dx.doi.org/10.4028/www.scientific.net/kem.767.240.

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“Detachable iron particles” or iron fines due to abrasive interactions in the roll bite between the roll surface and the strip are one of the major cleanliness defects. They may induce surface defects in particular on galvanizing lines. Chrome plating of rolls is generally recognized to result in a better strip surface cleanliness. In the present paper, the reasons for the success of chrome plating in this respect are investigated. An end-of-life industrial roll has been ground by parts under several conditions (Ra = 0.4 μm, 1.0 μm, 1.6 μm ± 0.1 μm), then cut into pieces for observation as well as for manufacturing tribological test tools (Plane Strain Compression Test, PSCT). Some of these pieces have been chrome-plated, the others not for comparison. Careful examination of just ground and chrome-plated roll has revealed that ground surface bears a number of rather aggressive features. Chrome plating covers them with a gentler pattern, although preserving the roughness in terms of Ra to maintain sufficient friction for correct mill operation. PSCT confirms that there is less wear debris on the strip when using Cr-plated tools.

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Yatribi, A., and A. Nejmeddine. "Impact écotoxicologique du traitement chimique des eaux usées de tanneries: Analyse technico-économique." Revue des sciences de l'eau 13, no. 2 (April 12, 2005): 107–18. http://dx.doi.org/10.7202/705384ar.

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La toxicité des eaux usées du tannage au chrome et d'épilage-pelanage, avant et après traitement, a été évaluée par test Daphnia pulex. Cette évaluation a été déterminée à partir des équations de corrélation linéaires. Les résultats obtenus montrent que le tannage au chrome et l'épilage-pelanage présentent une toxicité élevée avec des valeurs des CI50 24h respectives de 0,15 et 3,36. Cette toxicité élevée pourrait être expliquée par la charge de ces effluents en chrome, en sulfures et en matière organique. Après traitement par précipitation chimique, la CI50 24h a connu une importante augmentation. Elle est passée de 0,15 à 26,58 et de 3,36 à 11,1 respectivement pour le tannage au chrome et l'épilage-pelanage. Par conséquent, ces effluents traités peuvent être classés comme rejets peu toxiques. Cette diminution de la toxicité est liée surtout à l'abattement des MES (95 %), de la DCO (55 %), de Cr (90 %) et des sulfures (50 %). Ce traitement a donc, un double intérêt; le premier est environnemental, le second est économique du fait de la possibilité de recyclage du chrome récupéré dans le tannage du cuir. En effet, l'application expérimentale du chrome dans le tannage a montré un résultat similaire à celui obtenu par le produit commercial. Ainsi, suite à une analyse technico-économique, le bénéfice réalisé par cette opération est estimé à 3112,50 $ par 1000 tonnes par an.

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Khwaja, A. R., Rashmi Singh, and S. N. Tandon. "Recovery of Cr(III) from Tannery Spent Chrome Liquor for Reuse." Journal of Environmental Engineering 126, no. 4 (April 2000): 307–12. http://dx.doi.org/10.1061/(asce)0733-9372(2000)126:4(307).

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Stefaniuk, Ireneusz, Werner Obermayr, Volodymyr D. Popovych, Bogumił Cieniek, and Iwona Rogalska. "EPR Spectra of Sintered Cd1−xCrxTe Powdered Crystals with Various Cr Content." Materials 14, no. 13 (June 22, 2021): 3449. http://dx.doi.org/10.3390/ma14133449.

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In this paper, we show a simple method of producing ferromagnetic materials with a Curie temperature above room temperature. The electron paramagnetic resonance (EPR) spectra of Cd1−xCrxTe (0.002 < x < 0.08) were measured with a dependence on temperature (82 K < T < 381 K). Obtained EPR lines were fitted to a Lorentz-shaped curve. The temperature dependencies of the parameters of the EPR lines, such as the peak-to-peak linewidth (Hpp), the intensity (A), as well as the resonance field (Hr), were studied. Ferromagnetism was noticed in samples at high temperatures (near room temperature). For a sample with a nominal concentration of chrome of x = 0.05, a very strong intrinsic magnetic field is observed. The value of the effective gyromagnetic factor for this sample is ge = 30 at T = 240 K. An increase of chrome concentration above x = 0.05 reduces the ferromagnetic properties considerably. Analysis of the temperature dependencies of the integral intensity of EPR spectra was carried out using the Curie–Weiss law and the paramagnetic Curie temperature was obtained.

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Wang, Jingjing, Feng Jiang, Chaofu Tao, Han Yu, Laurent Ruhlmann, and Yongge Wei. "Oxidative esterification of alcohols by a single-side organically decorated Anderson-type chrome-based catalyst." Green Chemistry 23, no. 7 (2021): 2652–57. http://dx.doi.org/10.1039/d1gc00161b.

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An efficient strategy was reported for oxidative esterification reaction by a single-side organic decorated Anderson-type chrome-based catalyst in high yield. The Cr^IIIMo₆-OH could be simply recycled many times and maintain high catalytic activity.

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Pownceby, M., and P. Bourne. "Detrital chrome-spinel grains in heavy-mineral sand deposits from southeast Africa." Mineralogical Magazine 70, no. 1 (February 2006): 51–64. http://dx.doi.org/10.1180/0026461067010312.

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AbstractDetrital chrome-spinels are contaminant grains within ilmenite concentrates produced from heavy-mineral deposits along the coast of southeast Africa. The presence of even minor levels of chromia in the predominantly ilmenite-rich concentrates, downgrades their market value as potential feedstocks for the production of titania pigment. An understanding of their composition can assist in their removal from the ilmenite concentrates.Compositions from a database of close to 900 chrome-spinel analyses shows the major element components and their ranges (in wt.%) are: Cr: 0.4-45.3, Al: 0.0-31.0, Fe: 8.5-69.6 and Mg: 0.0-12.2. Minor components include Ti: 0.1-11.4 and Zn: 0.0-13.7.The chrome-spinel data fall into two compositionally distinct groups. The first group of spinels is dominated by a strong trend reflecting the mutual substitution between Al3+ and Cr3+ in the spinel structure. The second group of spinels is characterized by compositions containing abundant Fe3O4 magnetite component. The clear division between chrome-spinel compositional types indicates the grains are derived from at least two chemically dissimilar provenances.The compositional differences between the chrome-spinel groups has a positive impact on subsequent ilmenite upgrading treatments as the spinels which contain the highest magnetite component are easily removed via low-intensity magnetic separation procedures.

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Sarre, M. J., and M. Mazet. "Elimination de l'ion chrome hexavalent dans l'eau par les celluloses greffées." Revue des sciences de l'eau 1, no. 1-2 (April 12, 2005): 55–71. http://dx.doi.org/10.7202/705003ar.

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L'étude concerne le chrome (VI) et son élimination dans l'eau par les celluloses greffées (échangeuse d'anions) AE2 sous forme OH¯, Cl¯, S04=. La capacité d'échange correspond à 0,5-0,6 meq g-1 de cellulose. Les cinétiques d'échanges du Cr (VI) avec les ions CL¯ OH¯ et SO4 ont été déterminées en fonction du pH du milieu, de la température, de ta force ionique, de La quantité de détergents et des formes de celluloses AE2. Les résultats expérimentaux montrent que les formes de celluloses sont efficaces dans l'ordre OH¯ > Cl¯ > SO4= vis-à-vis du Cr (VI) et que l'échange décroît pour les ions étudiés dans l'ordre suivant : CrO4= > Cr207= > HCrO4¯.

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Kumšlytis, Vigantas, Algirdas Vaclovas Valiulis, and Olegas Černašejus. "Effect of PWHT on the Mechanical Properties of P5 Steel Welded Joints." Solid State Phenomena 165 (June 2010): 104–9. http://dx.doi.org/10.4028/www.scientific.net/ssp.165.104.

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Presented work analyses the impact of heat treatment parameters on the mechanical properties and operational reliability of P5 (5%Cr0.5%Mo) steel welded joints. The key objects of research are heat-treated chrome-molybdenum steel welded joints and piping elements operated at high temperature for an extensive period of time, where degradation of mechanical properties has been observed. The main objective is to investigate the causes of degradation of alloy steel mechanical properties during fabrication and operation of the equipment, and to develop a methodology for identification of optimum heat treatment parameters for chrome-molybdenum steel welded joints. A few key issues are addressed herein: identification of dependence of chrome-molybdenum (5%Cr-0.5%Mo) steel welded joint mechanical properties on heat treatment parameters, identification of the optimum value of temperature/time parameter, and identification of causes of mechanical property changes and degradation of the steel.

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35

Meekhanthong, K., and S. Wirojanupatump. "Characterization and Comparison of Thermally Sprayed Hard Coatings as Alternative to Hard Chrome Plating." Advanced Materials Research 974 (June 2014): 183–87. http://dx.doi.org/10.4028/www.scientific.net/amr.974.183.

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Thermal spray coatings have become one of the most potential for hard chrome replacement, particularly for wear and corrosion applications. In this study four types of hard coating materials were selected and thermally sprayed by suitable processes as the following designated codes (material/spray technique): Cr-Fe/HVOF, Cr-Ni/HVOF, WC-Ni/SF and Cr-Fe/AS. All of starting materials were characterized in order to create a correlation between spray materials and coating characteristics. SEM was employed for morphology and microstructure investigation. Particle size analysis was investigated by SEM and laser particle size analyzer. Coating characterization included surface roughness measurment by profilometer, porosity evaluation by image analysis and hardness test by Vicker microhardness tester. Microstructure of coatings was also revealed by SEM. Wear performance was evaluated by pin on disc test and dry sand rubber wheel abrasion test. Corrosion resistance was tested by potentiodynamic method. The results showed that particle size and morphology of starting powders were various depending on manufacturing method. Chemical compositions of starting materials showed great effect on coating properties and performance. Coatings deposited by HVOF and spray & fuse (SF) method showed typically dense and homogeneous structure than arc sprayed coating. WC-Ni/SF coating showed lowest abrasive wear rate compared to other thermally sprayed coatings. All Ni base coatings had significantly lower corrosion rates while Cr-Ni/HVOF coating had lowest corrosion rate. Although Cr-Ni/HVOF and WC-Ni/SF could be applicable for both wear and corrosion applications, for heat sensitive parts, Cr-Ni/HVOF coating could be a better alternative to spray and fuse.

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Beykaya, Mehmet, Zeliha Yıldırım, Ayşe Özbey, and Metin Yıldırım. "Sivas İlindeki Bazı Süt İşletmelerine Gelen Sütlerin Ağır Metal İçeriklerinin Belirlenmesi." Turkish Journal of Agriculture - Food Science and Technology 7, no. 1 (January 15, 2019): 105. http://dx.doi.org/10.24925/turjaf.v7i1.105-109.2164.

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In this study, some heavy metal contents, including cadmium (Cd), copper (Cu), chrome (Cr) and lead (Pb) of 50 raw bulk milk samples obtained from 5 different dairy plants in the Sivas and its vicinity were investigated. The contamination level of Cd, Cu and Cr were found 8.896, 33.69 and 31.81 µg/kg respectively in milk samples. Lead contents of 92% of the milk samples were below the detection limit, but 8% of the samples contained 304.1 - 503.4 µg/kg lead.

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Tiglyene, Souad, Abderrahim Jaouad, and Laila Mandi. "Mobilité et spéciation du chrome dans un système à phragmites australis de traitement des eaux usées de tanneries." Revue des sciences de l'eau 21, no. 1 (April 29, 2008): 1–16. http://dx.doi.org/10.7202/017927ar.

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Résumé L’objectif de ce travail est l’étude de la répartition, la migration, la spéciation et la biodisponibilité du Cr dans les différents horizons du sol au niveau d’un pilote à Phragmites australis (Cav.) Trin ex Steudel de traitement du rejet du tannage au chrome. Les résultats obtenus sont comparés à ceux d’un pilote non planté. La spéciation chimique du Cr total a été réalisée par cinq extractions séquentielles. L’extraction du chrome biodisponible est effectuée par CaCl2 (0,1 M). Les résultats de la répartition du Cr montrent que l’horizon superficiel renferme des teneurs élevées en Cr 80 % et que cette accumulation est statistiquement différente entre les deux pilotes (p<0,05) : 48 ± 4 g·kg-1 pour le système planté et 39 ± 7 g·kg-1 pour le système non planté. Les résultats de la spéciation chimique totale du Cr indiquent qu’il est très lié à la phase oxydable : 36 ± 10 % pour le système planté (PP) et 54 ± 9 % pour le système non planté (NPP). La teneur en Cr retenue dans la fraction résiduelle présente 26 ± 3 % et 25 ± 2 % respectivement pour le système PP et NPP. La proportion du Cr retenue dans la fraction carbonate est de 19,5 ± 5 % pour le système PP et 10,7 ± 5 % pour le système NPP. La part du Cr associée à la phase réductible présente 18 ± 6 % et 10 ± 4 % respectivement pour le système PP et NPP. Pour les deux pilotes le Cr total est peu échangeable et sa teneur biodisponible est faible. En outre, les résultats montrent que la présence de Phragmites australis a provoqué la libération partielle du Cr de la fraction organique mobile vers les formes carbonate et réductible relativement stables dans le système planté. Les résultats trouvés montrent que Phragmites australis présente une accumulation assez importante en Cr au niveau des racines : 1690 ± 124 mg·kg-1 en matière sèche. Le calcul du bilan global de l’épuration révèle que le Cr est surtout retenu par le sol (94 %) et que 5 % du Cr est prélevé par la plante. Cependant, la présence de Phragmites australis assure une porosité suffisante pour la percolation des eaux en traitement et permet le traitement d’un volume d’eau usée plus grand.

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Sherendo, Tatyana, Valentin Mitrofanov, Aleksey Vdovin, Petr Martyshko, Aleksey Alexeev, Dmitry Zamyatin, Vladimir Vazhenin, and Lidia Pamyatnykh. "Magnetic Clusters in Natural Ferro-Chromian Spinels." Solid State Phenomena 233-234 (July 2015): 587–90. http://dx.doi.org/10.4028/www.scientific.net/ssp.233-234.587.

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The results of investigations of natural iron-chromium spinels of variable composition Fe2+(Cr2-xFex3+)O4 of the chromite-bearing Klyuchevskoi massif (Middle Urals), which are the main carriers of the magnetization of rocks are presented. Substantial changes in the composition and in magnetic structure of accessory chrome-spinels scattered in the host rock are established, unlike the almost unaltered ore-forming chrome-spinels, under the influence of secondary geological processes. To establish the connection between the chrome-spinel changes at the microlevel and features of the geomagnetic field anomalies created by this carrier of magnetization of rocks, it is carried out a complex of investigations of Fe-Cr-spinels (thermomagnetic analysis over the temperature range (4÷1000) K; magnetic resonance (MR) spectroscopy and magnetic force microscopy (MFM) in addition to magnetomineralogical studies). As a result, in the relict areas of grains of the accessory chrome-spinels were first discovered the magnetic clusters (superparamagnetic phases) in the form of single or groups of 2 – 3 magnetic dipoles of tens nanometers in size, or in the form of chain-like structures of magnetic dipoles/single domains.

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Wu, Tuo, Yanling Zhang, Zheng Zhao, and Fang Yuan. "Effects of Fe2O3 on Reduction Process of Cr-Containing Solid Waste Self-Reduction Briquette and Relevant Mechanism." Metals 9, no. 1 (January 7, 2019): 51. http://dx.doi.org/10.3390/met9010051.

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High-temperature quench method, scanning electron microscope-energy dispersive spectroscopy (SEM-EDS), and thermodynamic analysis were adopted to study the effects of Fe2O3 on reduction process of Cr-containing solid waste self-reduction briquette (Cr-RB). Moreover, the relevant mechanism was also studied. The results clearly showed that the addition of Fe2O3 decreased the chromium-iron ratio (Cr/(Fe + Cr)) of Cr-RB itself and promoted the reduction of chrome oxide in the Cr-containing solid wastes such as stainless steel slag and dust. A large number of Fe-C alloy droplets generated in the lower temperature could decrease the activity of reduced chromium by in situ dissolution and the reduction of Cr-oxide was accelerated. Rapid separation of metal and slag could be achieved at a relatively lower temperature, which was very beneficial to the efficient recovery of Cr. Finally, the corresponding mechanism diagram was presented.

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Xing, J., and M. T. Pailthorpe. "Low Chrome Dyeing: Eliminating Cr(VI) in the Exhausted Bath by Using Cr(III) as the Mordant." Textile Research Journal 65, no. 2 (February 1995): 70–74. http://dx.doi.org/10.1177/004051759506500202.

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Jeong, Il Heon, Yeong Min Park, Jae Uk Yoo, and Tae Gyu Kim. "A study on the mechanical properties of forged high chrome steel heat resistant materials." Modern Physics Letters B 34, no. 07n09 (March 11, 2020): 2040036. http://dx.doi.org/10.1142/s0217984920400369.

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High chrome steel (12 Cr-steel) is the material found in engine blade which required high durability and long service life at high temperatures. Therefore, it is important to produce durable and high strength 12 Cr-steel. In this study, effect of different tempering temperature on microstructure of 12 Cr-steel specimens were investigated. First, the specimens were heat treated to 1070[Formula: see text]C and quenched in an acidic solution. Then they were tempered at different temperature at 470[Formula: see text]C and 690[Formula: see text]C. Analyses on mechanical properties such as hardness, yield strength, tensile stress were performed. It is found that specimen at lower temperature (470[Formula: see text]C) has improved mechanical properties.

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Zhao, Wenhua, Zhiqiang Wei, Li Zhang, Xiaojuan Wu, Xuan Wang, and Jinlong Jiang. "Room Temperature Ferromagnetic and Optical Properties of Chrome Doped ZnS Nanorods Prepared by Hydrothermal Method." Journal of Nanomaterials 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/9378349.

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Cr doped Zn1-xCrxS nanorods with different concentration ratio (x=0, 0.01, 0.03, and 0.05) were successfully synthesized by hydrothermal method. The crystal microstructure, morphology, chemical composition, and optical and magnetic properties of the samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS), diffuse-reflectance spectroscopy (DRS), photoluminescence (PL) spectra, and the vibrating sample magnetometer (VSM). All the samples synthesized by this method exhibited single-phase wurtzite structure with good crystallization as demonstrated by XRD studies, which indicated that all Cr ions successfully substituted for the lattice site of Zn2+ and generated single-phase Zn1-xCrxS. DRS revealed the band gap of doped Zn1-xCrxS underwent blue shift compared to that of the bulk ZnS. PL spectra showed obvious ultraviolet emission peak at 375 nm and two blue emissions appear about 500 and 580 nm. The blue emissions intensity of doped samples improved with the increase of Cr concentration, comparing to pure ZnS. Magnetic measurements indicated that the undoped and doped ZnS nanorods exhibited well-defined ferromagnetic behavior at room temperature. The saturation magnetization weakened significantly with increasing Cr concentration comparing to pure ZnS and reached minimum for 3% Cr.

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Costa, G., M. J. Ribeiro, Tito Trindade, and Joao A. Labrincha. "Development of Waste-Containing Malayaite Ceramic Pigments." Advances in Science and Technology 45 (October 2006): 2229–34. http://dx.doi.org/10.4028/www.scientific.net/ast.45.2229.

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The preparation of ceramic pigments using industrial waste, a galvanizing sludge from the Cr/Ni plating process, as primary source is here reported. The ceramic pigments were prepared using the common solid state reaction process, investigating the optimal formulation, milling and firing conditions. The main focus will be given on the synthesis of chrome-tin red malayaite Ca(Cr,Sn)SiO5 pigment that was fully characterised and then tested in a standard ceramic glaze. Typical working conditions and colour development will be also reported.

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Méndez-Albores, Alia, Sandra G. González-Arellano, Yolanda Reyes-Vidal, Julieta Torres, Ştefan Ţălu, Bibiana Cercado, and Gabriel Trejo. "Electrodeposited chrome/silver nanoparticle (Cr/AgNPs) composite coatings: Characterization and antibacterial activity." Journal of Alloys and Compounds 710 (July 2017): 302–11. http://dx.doi.org/10.1016/j.jallcom.2017.03.226.

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Ribeiro, Ana, W. Hajjaji, M. P. Seabra, and J. A. Labrincha. "Malayaite Ceramic Pigments Prepared from Industrial Wastes: Formulation and Characterization." Materials Science Forum 636-637 (January 2010): 1371–76. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.1371.

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In this work chrome-tin red malayaite pigments Ca(Cr,Sn)SiO5 were obtained from industrial wastes: a marble sawing sludge, a galvanizing sludge from the Cr/Ni process and a foundry sand. The pigments were prepared using the common solid state reaction process. The influence of Cr2O3/SnO2 ratio, calcination temperature and introduced sludges compositions, on its structural stability, was investigated by X-ray diffraction coupled with SEM/EDS. Standard formulations, obtained from commercial reagents, were also prepared and characterized for sake of comparison. CIELab colour measurements and UV-Vis spectroscopy were used to evaluate the stability (thermal and chemical) and applicability of the synthesized pigments in colouring distinct ceramic matrixes fired at high temperatures (1050°C-1200°C). The pigment was added (1/20 wt. ratio) to a transparent and shining lead free glaze and to a porcelain stoneware body (1/10 wt. ratio). The incorporation of three industrial wastes, in the chrome-tin red malayaite pigment, was possible without a notorious change in terms of colouring effect allowing decreasing the synthesis temperature.

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Xu, Bin, Le Yang, Shi Bo Xing, and Li Li. "Effect of Plastic Deformation at Room Temperature on Powder RE-Chrome-Boronizing for Medium Carbon Steel." Key Engineering Materials 353-358 (September 2007): 575–78. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.575.

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In order to increase boronizing speed without decreasing the hardness of boride layer, the effect of plastic deformation at room temperature on powder RE-chrome-boronizing for a medium carbon steel (steel 45), in which boronizing plays a main role, was studied in this paper. The cold plastic deformation (CPD), whether compressing or shot-peening, can increase boronizing speed. Meanwhile, the boride layer can also retain its high microhardness (1 300―1 900HV0.1) with low brittleness. The layer depth achieved for a given heating time increases with increasing CPD degree on the steel. The analyses show that boronizing kinetics in the RE-chrome-boronizing (RE-Cr-B) samples with CPD can be enhanced.

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Li, Zeng Zin, Guo Ming Wang, and Wen Jun Li. "A Comparative Research on Different Preparation Methods of Furfural Hydrogenation Non-Chromium Catalysts." Advanced Materials Research 599 (November 2012): 27–31. http://dx.doi.org/10.4028/www.scientific.net/amr.599.27.

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Furfuryl alcohol is an important organic chemical material. The traditional catalysts of furfural hydrogenation to produce furfuryl alcohol contain Cr, which is harmful to people’s health and causes severe environmental pollution. Developing new highly active catalysts in furfuryl alcohol is of great practical significance. The progress of non-chrome catalysts for hydrogenation of furfural to produce furfuryl alcohol has been reviewed. Some environmental-friendly non-chrome catalysts, such as copper catalysts, CuO-CaO/SiO2 catalysts, Cu-Zn-Al catalysts, load Ni and ultra-fine Ni-B amorphous alloy catalysts, had been discussed and their preparations and structure characterizations were described. Some constructive strategies are presented for the research and applications of such catalysts.

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Iddou, Abdelkader, and Mohand Said Ouali. "Étude de l'élimination de Cr(VI) par une boue biologique après épandage." Water Quality Research Journal 40, no. 2 (May 1, 2005): 184–90. http://dx.doi.org/10.2166/wqrj.2005.021.

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Abstract Plusieurs industries, telles que les tanneries, la métallurgie, de traitement de surface, etc, produisent des quantités significatives de déchets liquides riches en élément chrome sous sa forme de Cr(VI). Cette étude traite de l'élimination de cette espèce chimique très toxique. Les expériences ont été effectuées en « batch » sous agitation et le matériau utilisé est une boue de station d'épuration biologique après épandage. Plusieurs facteurs physico-chimiques jouent un rôle dans l'efficacité de l'élimination de l'espèce étudiée sur le support choisi. En effet, des observations de l'influence qu'ont sur le processus des facteurs tels que la variation de la concentration initiale du Cr(VI), le rapport solide/solution ainsi que l'apport en oxygène au système permettent de suggérer un mécanisme d'élimination. L'étude a montré qu'il est nécessaire que la flore microbienne présente dans le support s'adapte au milieu auquel elle est soumise. Cette adaptation est d'autant plus importante que les espèces responsables de l'élimination du Cr(VI) sont plus efficaces à des concentrations inférieures à 30 mg/L, avec des taux d'élimination de 100% au bout de 48 heures. Une plus grande efficacité du système fermé et une cinétique d'ordre 1 sont mises en évidence L'utilisation de ce genre de matériau dans le traitement des eaux en général, et des eaux chargées en élément Cr(VI) en particulier, permettrait d'une part la réduction des déchets des stations d'épuration biologique des eaux et d'autre part, l'élimination totale de l'élément toxique Cr(VI) à de faibles concentrations, entraînant ainsi la baisse du coût d'exploitation dans les stations d'épuration de rejets chargés en chrome de certaines industries telle que celle de traitement de surface.

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Jabbaripour, B., M. H. Sadeghi, Mohammad Reza Shabgard, S. Shajari, and H. Hassanpour. "Investigating the Effects of Powder Mixed Electrical Discharge Machining on the Surface Quality of γ–TiAl Intermetallic." Advanced Materials Research 488-489 (March 2012): 396–401. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.396.

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Due to outstanding properties of γ–TiAl intermetallic such as high resistance against fatigue, oxidation, corrosion, creep, dynamic vibration, high working temperature and also its application in aerospace, automotive industry and turbojet engines; in this paper, powder mixed electrical discharge machining (PMEDM) of γ–TiAl intermetallic by means of different additive powders including aluminum (Al), graphite (Gr), silicon carbide (SiC), chrome (Cr) and iron (Fe) is investigated to compare the output characteristic of surface quality and roughness. The results indicate that aluminum powder produces the best surface finish, followed by silicon carbide, graphite, chrome and iron respectively. The experimental results show that in the determined settings of input machining parameters, aluminum powder can improve the surface roughness of TiAl sample about 32%.

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Maischner, Dora, Udo Fritsching, Anoop Kini, Andreas Weisheit, Volker Uhlenwinkel, Johannes Henrich Schleifenbaum, and Tim Biermann. "Laser additive manufacturing of copper– chromium–niobium alloys using gas atomized powder." International Journal of Materials Research 111, no. 7 (August 1, 2020): 587–93. http://dx.doi.org/10.1515/ijmr-2020-1110708.

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Abstract Copper-chrome-niobium alloys exhibit excellent thermal and electrical properties combined with high strength at elevated temperatures. Additive manufacturing techniques such as laser metal deposition using powder as raw material offer the potential for rapid solidification as well as a high freedom of design to manufacture parts layer by layer. Powder samples of copper- chrome-niobium alloys were produced by gas atomization. Via laser metal deposition, bulk volumes without cracks and with a very low porosity can be built up. Rapid solidification leads to the formation of fine precipitates which are likely to be (Cr,Fe)2Nb. The precipitates are distributed homogeneously in the copper matrix. The copper crystals grow across the layers due to epitaxial nucleation on the preceding layer.

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Journal articles on the topic 'Cr [chrome]'

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