Articoli di riviste: "CERAMICS DOPED"

1

Wang, Ning Zhang, Sha Sha e Yu Tian Ma. "Influence of Doped Mn, Cu, Ni and Fe on Electrical Properties of SrTiO₃ Ceramics". Advanced Materials Research 79-82 (agosto 2009): 1603–6. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.1603.

Testo completo

Abstract (sommario):

MnCO3, CuO, NiO and Fe2O3 doped SrTiO3 multifunction ceramics were fabricated firstly. The microstructure and electrical properties were investigated. The results show that MnCO3 doped ceramic and CuO doped ceramic possess relative higher resistivity (ρ),nonlinear coefficient (α), varistor voltage (V1mA) and relative lower dielectric constant (ε),dielectric loss (tgδ) in contrast with NiO doped ceramic and Fe2O3 doped ceramic with the same contents under the same sintering conditions. The electrical properties among the ceramics doped are different due to the different behaviors of Mn,Cu,Ni and Fe acceptor dopants during the sintering course.

Gli stili APA, Harvard, Vancouver, ISO e altri

2

Liu, Yantao, Ying Wang e Jianping Ma. "Study on Structural, Electrical and Magnetical Properties of Zn Doped CuAlO₂ Ceramics". Journal of Physics: Conference Series 2342, n. 1 (1 settembre 2022): 012010. http://dx.doi.org/10.1088/1742-6596/2342/1/012010.

Testo completo

Abstract (sommario):

Abstract To improve the properties of CuAlO2 thin films, the preparation of CuAlO2 ceramics with excellent properties is an important prerequisite, and the optimization of ceramic properties is often achieved by doping. Zn-doped CuAlO2 ceramics were prepared by the solid phase sintering method. The structural, electrical and magnetic properties of Zn-doped CuAlO2 ceramics were systematically studied. The results show that the crystal structure of the as-sintered Zn-doped CuAlO2 was rhombohedral, space group R3m. Grain size of samples grew with the amount of Zn increases, which is related to the enhancement of CuAl2O4 phases in the sample ceramics. The density of doped ceramics changed when increasing Zn-doping concentration compared to undoped ceramics. It reached a minimum 0.96 g/cm3. The resistivity of Zn-doped CuAlO2 ceramic samples climbed with the increase of Zn content, and it can reach 59.6 Ω•cm at 10 mol%. The ferromagnetic behavior was enhanced with increasing the Zn concentration.

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Li, Chao, Jin-Su Baek e Jung-Hyuk Koh. "Ce and Y Co-Doping Effects for (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 Lead-Free Ceramics". Coatings 11, n. 10 (14 ottobre 2021): 1248. http://dx.doi.org/10.3390/coatings11101248.

Testo completo

Abstract (sommario):

CeO2 and Y2O3 were co-doped to (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 ceramics and sintered by conventional solid-state reaction process to form x wt.% CeO2-y wt.% Y2O3 doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (CexYy-BCZT) ceramics. The effects of different contents of CeO2-Y2O3 dopants to the (Ba0.85Ca0.15) (Zr0.1Ti0.9)O3 composition were analyzed by studying the phase, surface microstructure, piezoelectric and ferroelectric properties of BCZT ceramics. In this study, we have shown that co-doping a small amount of CeO2 and Y2O3 will not change the phase structure of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 ceramics. However, the proper introduction of CeO2 and Y2O3 can improve the piezoelectric constant and electromechanical coupling coefficient of BCZT ceramic samples. Moreover, these dopants can promote the grain growth process in (Ba0.85Ca0.15) (Zr0.1Ti0.9)O3 ceramics. C0.04Y0.02 doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 ceramic has the best piezoelectric properties compared with other composition, the results are as follows: Relative density = 96.9%, Kp = 0.583, and d33 = 678 pC/N, V = 8.9 V. It means that this Ce0.04Y0.02 doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 ceramic is a desired material in the application of lead-free ceramics.

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Huang, Xin You, Yuan Zuo e Chun Hua Gao. "Influence of Titanium Ion Doped Amount on the Dielectric Property of BMNT Ceramics". Advanced Materials Research 760-762 (settembre 2013): 772–75. http://dx.doi.org/10.4028/www.scientific.net/amr.760-762.772.

Testo completo

Abstract (sommario):

Bi2(Mgl/3Nb2/3-xTix)2O7(BMNT)(x=0.1, 0.15, 0.2, 0.25) ceramics was prepared by conventional solid phase method, The influence of titanium ion doped amount on the dielectric property and microstructure of BMNT ceramics were systematically studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and other testing and analysis how to methods. Results show that there is single monoclinic pyrochlore phase and there is not the second phase in all BMNT ceramics doped with titanium ion. The grain size of BMNT ceramics increases first and then decreases, the dielectric constant (εr) increases first and then decreases, the dielectric loss (tanδ) increases first and then decreases, the ceramic density decreases all the time while titanium ion doped amount increases. The ceramic density increases first and then decreases when sintered temperature increases. The density of BMNT ceramics doped with titanium ion is biggest when sintered temperature is 980 °C. When sintered temperature is 980 °C and titanium ion doped amount is 0.15mol, the dielectric properties of BMNT ceramics is good,which εris 135(1MHz), tanδ is 0.002(1MHz) and volume density is 7.46g/cm3.

Gli stili APA, Harvard, Vancouver, ISO e altri

5

Wu, Yun Yi, Lei Wang, Zhi Qiang Hua, Tao Li, Xue Tao Yuan e Xu Dong Lv. "Effects of Ion Doping at Different Sites on Electrical Properties of Ferroelectric Bi₄Ti₃O₁₂ Ceramics". Advanced Materials Research 399-401 (novembre 2011): 796–804. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.796.

Testo completo

Abstract (sommario):

Pure, La3+doped at A site, V5+doped at B site, and La3+and V5+co-doped ferroelectric Bi4Ti3O12(BTO), Bi3.25La0.75Ti3O12(BLT), Bi4Ti2.98V0.02O3(BTV) and Bi3.25La0.75Ti2.98V0.02O12(BLTV) were successfully prepared by conventional sintering technique. The structures of the ceramics were investigated by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. X-ray diffraction indicated that assemblages of all sintered ceramics consist of a single phase of Bi4Ti3O12, implying that the A-site La3+and B-site V5+substitutions in this case do not affect the layered structure. Among these ceramics, BLTV ceramic exhibited the best electrical properties. The leakage current density of BLTV ceramic was only 1.3×10-4Acm-2at 40 KVcm-1, two orders of magnitude lower than BTO ceramic. Besides, a saturated ferroelectric hysteresis loops with largest remnant polarization 2Pr of 30.6μC/cm2was observed for this sample. These suggested that the co-doped Bi4Ti3O12ceramic by La3+and V5+at A and B sites showed advantages in application over the pure BTO, doped BLT and BTV ceramic, respectively.

Gli stili APA, Harvard, Vancouver, ISO e altri

6

Wang, Ning Zhang, e Zhang Wen. "Effects of Doped Cu, Mn on Electrical Properties of SrTiO₃-Based Varistor Ceramics". Advanced Materials Research 399-401 (novembre 2011): 783–87. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.783.

Testo completo

Abstract (sommario):

CuO and MnCO3 doped SrTiO3-based multifunction ceramics were prepared respectively with solid state reaction method under vacuum condition. The electrical properties’ change with the oxidation temperature and microstructure were investigated. The results show that acceptor dopants behaves differently with the same sintering conditions. CuO-doped ceramic possess relative higher dielectric loss, dielectric constant and relative lower nonlinear coefficient, varistor voltage in contrast with MnCO3 doped ceramic with the same contents under the same sintering conditions. The grain size of CuO-doped sample is significantly larger than the sample doped with MnCO3. The grain distributions of CuO-doped sample is more homogeneous. The electrical properties of the ceramics are different due to the different behaviors of CuO and MnCO3 accepter dopants during the sintering process.

Gli stili APA, Harvard, Vancouver, ISO e altri

7

Zhou, You, Kiyoshi Hirao, Motohiro Toriyama e Hidehiko Tanaka. "Silicon carbide ceramics prepared by pulse electric current sintering of β–SiC and α–SiC powders with oxide and nonoxide additives". Journal of Materials Research 14, n. 8 (agosto 1999): 3363–69. http://dx.doi.org/10.1557/jmr.1999.0455.

Testo completo

Abstract (sommario):

Using a pulse electric current sintering (PECS) method, β–SiC and α–SiC powders doped with a few weight percent of Al2O3–Y2O3oxide or Al4C3–B4C–C nonoxide additives were rapidly densified to high densities (95.2–99.7%) within less than 30 min of total processing time. When Al2O3–Y2O3additive was used, both ceramics resulting from β–SiC and α–SiC had fine, equiaxed microstructures. In contrast, when Al4C3–B4C–C additive was used, the ceramic resulting from α–SiC had a coarse, equiaxed microstructure, whereas the ceramic resulting from β–SiC was composed of large elongated grains whose formation was accompanied by the β →?α phase transformation of SiC. Compared with the Al2O3–Y2O3-doped SiC ceramics, the Al4C3–B4C–C-doped SiC ceramics had higher densities, lower fracture toughness, and higher hardness. The fracture mode of the oxide-doped SiC was mainly intergranular, whereas the nonoxide-doped SiC exhibited almost complete intragranular fracture that was attributed to the higher interfacial bonding strength.

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Wu, Botao, Jianrong Qiu, Nan Jiang, Shifeng Zhou, Jinjun Ren, Danping Chen, Xiongwei Jiang e Congshan Zhu. "Optical properties of transparent alkali gallium silicate glass-ceramics containing Ni2+-doped β-Ga2O3 nanocrystals". Journal of Materials Research 22, n. 12 (dicembre 2007): 3410–14. http://dx.doi.org/10.1557/jmr.2007.0429.

Testo completo

Abstract (sommario):

Broadband near-infrared (IR) luminescence in transparent alkali gallium silicate glass-ceramics containing Ni2+-doped β-Ga2O3 nanocrystals was observed. This broadband emission could be attributed to the 3T2g (3F) → 3A2g (3F) transition of octahedral Ni2+ ions in glass-ceramics. The full width at half-maximum (FWHM) of the near-IR luminescence and fluorescent lifetime of the glass-ceramic doped with 0.10 mol% NiO were 260 nm and ∼1220 μs, respectively. It is expected that transparent Ni2+-doped β-Ga2O3 glass-ceramics with this broad near-IR emission and long fluorescent lifetime have potential applications as super-broadband optical amplification media.

Gli stili APA, Harvard, Vancouver, ISO e altri

9

Plutenko, Tetiana, Oleg V'yunov, Oleksandr Fedorchuk, Oleg Yanchevskii e Pavlo Torchyniuk. "Al-DOPED LANTHANUM-LITHIUM TITANATE WITH HIGH DIELECTRIC CONSTANT". Ukrainian Chemistry Journal 89, n. 6 (28 luglio 2023): 71–78. http://dx.doi.org/10.33609/2708-129x.89.06.2023.71-78.

Testo completo

Abstract (sommario):

La0.67LixTi1-xAlxO3 ceramics (x = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30) were synthesized with the use of Al2O3 and an aqueous solution of Al(NO3)3 as an aluminium source. In both cases, the ceramics preserve a high dielectric constant ε ~ 105. It was found that the single-phase La0.67LixTi1-xAlxO3 perovskite structure is formed at temperatures above 1200 C. It was shown that the use of Al(NO3)3 allows simplifying the synthesis: reduction in the sintering temperature by 20 C, Li loss and, as a result, an increase in the density of ceramics. Ceramics La0.67Li0.15Ti0.85Al0.15O3 with a maximum density higher than 85 % were sintered at about 1280 and 1300 C of with the use of Al(NO3)3 and Al2O3 respectively. Frequency spectra of imaginary parts of impedance and electrical modulus demonstrate two dispersion regions that refer to processes in the ceramic grains’ boundaries and ceramic grains. Ceramic samples synthesized using Al(NO3)3 solutions tend to exhibit higher dielectric constants than those synthesized using Al2O3. At a frequency of 100 Hz, the dielectric constant for ceramics synthesized using Al(NO3)3 aqueous solution is 70600, whereas that for ceramics synthesized using Al2O3 is 44300. Obtained materials are useful for microelectronics, energy storage and harvesting devices.

Gli stili APA, Harvard, Vancouver, ISO e altri

10

Zhang, Jiameng, Yanan Hao, Meihua Bi, Guoyan Dong, Xiaoming Liu e Ke Bi. "Outstanding Photoluminescence in Pr3+-Doped Perovskite Ceramics". Micromachines 9, n. 9 (21 agosto 2018): 419. http://dx.doi.org/10.3390/mi9090419.

Testo completo

Abstract (sommario):

Ba (Zr0.2Ti0.8) O3-50% (Ba0.7Ca0.3) TiO3 (BZT-0.5BCT) ceramics with different doping contents of Pr3+ were prepared by the conventional solid-state reaction. The phase structure and crystallinity of the fabricated ceramics were investigated by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Photoluminescence (PL) emission spectra were measured to analyze the PL characteristics. The strong intensities of a green band at 489 nm and a red band at 610 nm were observed. The maximum emission intensity of the PL spectrum was achieved in the BZT-0.5BCT ceramic with 0.2% mol of Pr3+ ions. Furthermore, the PL spectra of BZT-0.5BCT ceramics were found to be sensitive to polarization of the ferroelectric ceramics. Compared with the unpoled ceramics, the green emission increased about 42% and a new emission peak at 430 nm appeared for the poled ceramics. With excellent intrinsic ferroelectricity and an enhanced PL property, such material has potential to realize multifunctionality in a wide application range.

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Qin, Qun, Tian Guo Wang e Wen Jun Zhang. "Effect of Er₂O₃ on the Microstructure and Electrical Properties of WO₃ Capacitor-Varistor Ceramics". Advanced Materials Research 233-235 (maggio 2011): 2503–6. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.2503.

Testo completo

Abstract (sommario):

WO3-based capacitor-varistor ceramics doped with Er2O3 were prepared and the microstructures and nonlinear electrical properties were investigated. The results show that there exist second phase Er10W2O21 on the surface of WO3 grains. Doping Er2O3 in WO3 ceramic can inhibit the grain growth. A small quantity of Er2O3 can significantly improve nonlinear properties of the samples. The permittivity of doped samples was higher than that of the undoped, and the high permittivity makes Er2O3-doped WO3 ceramics be applicable as a kind of capacitor-varistor materials.

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Melnichuk, O. V., N. O. Korsunska, I. V. Markevich, V. V. Boyko, Yu O. Polishchuk, Z. F. Tsybrii, L. Yu Melnichuk, Ye F. Venger, V. P. Kladko e L. Yu Khomenkova. "Peculiarities of specular infrared reflection spectra of ZnO-based ceramics". Semiconductor Physics, Quantum Electronics and Optoelectronics 24, n. 04 (23 novembre 2021): 390–98. http://dx.doi.org/10.15407/spqeo24.04.390.

Testo completo

Abstract (sommario):

Undoped and Mn-doped ZnO ceramics were theoretically and experimentally investigated using specular infrared reflection method. It was shown that infrared reflection spectra can be modeled using the parameters explored for ZnO single crystals. For ceramic samples, it was shown that ZnO grains with orientation of the C-axis along the normal to the electric field ( ) give the main contribution to IR reflection spectra. It has been ascertained that the surface roughness is manifested in these spectra mainly within the range 450…550 cm–1 giving negligible effect for the frequencies above longitudinal phonon frequency. This allowed the electrophysical parameters of ZnO crystallites to be evaluated. In the case of undoped ceramics, the obtained results were found to be consistent with the values of direct current measurements. This finding supports the utility of infrared spectroscopy for determination of the electrophysical parameters of polycrystalline ceramic materials. For Mn-doped ceramic samples, the conductivity value measured using the direct current method was found to be essentially lower than those determined from simulation of infrared reflection spectra. This phenomenon was explained by barrier formation at the grain boundaries in Mn-doped ZnO ceramics.

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Feng, Dandan, Xiaojing Wang, Shike Zhao, Baipeng Song e Guanjun Zhang. "Study of TiO2 on the Voltage Holdoff Capacity of Cr/Mn-Doped Al2O3 Ceramic in Vacuum". Materials 16, n. 14 (17 luglio 2023): 5048. http://dx.doi.org/10.3390/ma16145048.

Testo completo

Abstract (sommario):

With the development of vacuum electronic devices toward high power, high frequency, and miniaturization, the voltage holdoff capacity of the insulation materials in devices has also been raised to a higher demand. Cr/Mn/Ti-doped Al2O3 ceramics were prepared, and the bulk density, micromorphology, phase composition, resistivity, secondary electron emission coefficient, and surface flashover threshold in the vacuum of the Al2O3 were characterized. The results show that the addition of TiO2 to the Al2O3 ceramic can promote the sintering of the ceramic. The Cr/Mn/Ti-doped Al2O3 ceramic with a homogeneous microstructure can be obtained by an appropriate amount of TiO2 addition. In the process of the heat treatment, the TiO2 in the ceramics was reduced to a certain degree, which had an impact on the microstructure of the Al2O3 ceramic. Adding a small amount of TiO2 can improve the voltage holdoff performance in the vacuum. The value of the surface flashover threshold in the vacuum of the Cr/Mn/Ti-doped Al2O3 ceramic containing 1 wt.% TiO2 reached a value of 33 kV, which is 32% higher than that of the basic Al2O3 ceramic. The preparation of Al2O3 ceramics with a high voltage holdoff capacity in a vacuum provides fundamental technical support for the development of vacuum electronic devices.

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Rerak, Michał, Jolanta Makowska, Małgorzata Adamczyk-Habrajska e Lucjan Kozielski. "Impedance Spectroscopy of Pr-Doped BaBi2Nb2O9 Aurivillius Ceramics". Materials 15, n. 18 (11 settembre 2022): 6308. http://dx.doi.org/10.3390/ma15186308.

Testo completo

Abstract (sommario):

Herein this study, the polycrystalline nature of the Aurivillius type structure is studied; primarily, the main objective is to observe the influence of dopant Pr3+ at the Ba2+-site of BaBi2Nb2O9 (BBN) ceramics. The ceramics under investigation were fabricated via the conventional solid-state reaction method. Scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) techniques were used to analyse their morphological structure. It was found that the chemical composition of the ceramic samples corresponds well to the initial stoichiometry of the ceramic powders. An increase in praseodymium content caused a slight decrease in the average size of the ceramic grains. The obtained ceramic materials are described by a tetragonal structure with the space group I4/mmm. The electrical properties of the material have been studied using complex impedance spectroscopy methods in wide temperature and frequency ranges. The analysis of obtained results showed grains and grain boundaries contribute to conductive processes in the material. A possible ’hopping’ mechanism for electrical transport processes in the system is evident from the analysis of results based on Joncher law.

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Fujii, Ichiro, Ryuta Mitsui, Kouichi Nakashima e Satoshi Wada. "Enhanced piezoelectric properties of (Ba0.3Bi0.7)(Mg0.05Fe0.6Ti0.35)O3 piezoelectric ceramics with high Curie temperature". Journal of Advanced Dielectrics 04, n. 01 (gennaio 2014): 1450005. http://dx.doi.org/10.1142/s2010135x14500052.

Testo completo

Abstract (sommario):

( Ba 0.3 Bi 0.7)( Mg 0.05 Fe 0.6 Ti 0.35) O 3 ceramics were either doped with vanadium or sintered in calcined powder with the same composition. Compared to an undoped ceramic sintered without the calcined powder, both ceramics showed reduced leakage current densities (lower than 1 × 10-7 A/cm2) and absence of dielectric relaxation behaviors observed in frequency- and temperature-dependent dielectric measurements. The Curie temperatures of both samples were higher than 460°C. The maximum field-induced strain over the applied field, S max /E max , of 366 pm/V of the undoped ceramic sintered without the calcined powder increased to 455 and 799 pm/V for the V-doped ceramics and the ceramics sintered with the calcined powder, respectively. The increase was related to a reduced concentration of bismuth vacancy–oxygen vacancy defect dipoles.

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Wang, Tian Guo, Qun Qin e Wen Jun Zhang. "Effect of La₂O₃ on the Electrical Properties of WO₃-Based Varistor Ceramics". Key Engineering Materials 480-481 (giugno 2011): 137–41. http://dx.doi.org/10.4028/www.scientific.net/kem.480-481.137.

Testo completo

Abstract (sommario):

The nonlinear electrical behavior and dielectric properties of WO3-based ceramics with various La2O3 contents have been investigated. Breakdown voltages Eb of WO3 doped with La2O3 are lower than that of undoped WO3, indicating that the dopant can reduce the breakdown voltage. The dielectric constant of doped samples is higher than that of undoped samples, and the high dielectric constant makes them suitable as capacitor-varistor materials. The theory defects in the crystal lattice was introduced to explain the nonlinear electricial behavior of the La2O3-doped WO3 ceramics. In view of these electrical characteristics, the WO3 ceramic doped with La2O3 is a viable candidate for capacitor-varistor functional devices.

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Zhu, Zhi Wen, Xin You Huang, Hai Tang Hua e Yan Li. "Study on the Property of Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃ Lead-Free Piezoelectric Ceramics Doped with Li₂CO₃". Advanced Materials Research 549 (luglio 2012): 651–54. http://dx.doi.org/10.4028/www.scientific.net/amr.549.651.

Testo completo

Abstract (sommario):

Ba0.85Ca0.15Ti0.9Zr0.1O3-xLi2CO3 lead-free piezoelectric ceramics (abbreviated as BCZT-xLi) were prepared by conventional solid state reaction method. The microstructure, piezoelectric properties and dielectric properties were studied for BCZT-xLi samples doped with different Li2CO3 content(x= 0, 0.05, 0.1 0.2 0.3, 0.4wt. %). The results show that the piezoelectric constant(d33), planar electron mechanical coupling coefficient(kp) and thickness electron mechanical(kt) of BCZ-T-xLi ceramics increase firstly and decreases subsequently with increasing of Li+ doping amount, the dielectric loss(tanδ) of BCZT-xLi ceramics decreases firstly and then increases at the same time while Li+ doping amount increases. But the r-elative permittivity (εr) of BCZT-xLi ceramics increases all the time. With the in-creasing of the amount of Li2CO3 doped the grain size of BCZT-Li ceramic first increases and then decreases. The BCZT-xLi ceramics display the optimum properties (d33=83, tanδ=0.035, εr=2020, kp=0.41, kt=0.046) while Li2CO3 doped amount is 0.20wt. %.

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Gu, Yong Jun, Jin Liang Huang, Wei Hu, Qian Li, Li Hua Li e Hui Xu. "Low Temperature Sintering of Ca_0.6La_0.8/3TiO₃-Li_0.5Nd_0.5TiO₃ Ceramics with ZnO-B₂O₃-SiO₂ Glass Addition". Advanced Materials Research 335-336 (settembre 2011): 956–59. http://dx.doi.org/10.4028/www.scientific.net/amr.335-336.956.

Testo completo

Abstract (sommario):

The sintering behaviors and microwave dielectric properties of the Ca0.6La0.8/3TiO3-Li0.5Nd0.5TiO3 (abbreviated CLLNT) ceramics doped by small amounts of ZnO-B2O3-SiO2 glass were investigated in this paper. The adding of ZnO-B2O3-SiO2 glass improved the densifications of the CLLNT ceramics and the sintering temperature of the CLLNT ceramic had been efficiently lowered to 1050°C. Especially, the 8wt% ZnO-B2O3-SiO2 glass doped CLLNT ceramic sintered at 1050°C for 3 h has optimum microwave dielectric properties of Kr=89, Q×f=1445GHz, and TCF=11.4 ppm/°C and it should be a suitable candidate for LTCC applications.

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Wang, Xianwen, Xiangping Jiang, Xin Nie, Xiaokun Huang, Chao Chen, Jun Wang, Jingdong Xu e Liwei Huang. "Piezoelectric properties of cerium-doped bismuth barium titanate intergrowth ceramics". Processing and Application of Ceramics 15, n. 2 (2021): 120–27. http://dx.doi.org/10.2298/pac2102120w.

Testo completo

Abstract (sommario):

Structure and electrical properties of cerium doped bismuth barium titanate Ba1-xCexBi8Ti7O27 (x = 0, 0.05, 0.1, 0.15, 0,2 and 0.3) ceramics were investigated. X-ray diffraction revealed that the ceramic samples are of single stable phase. The ceramics possess typical plate-like structure with obvious decrease in the grain size with increasing Ce-doping amount. The dielectric properties of the materials show relaxor behaviour. Furthermore, the total resistance increase was observed with Ce-doping and the doped samples show good insulation properties. The Ba0.9Ce0.1Bi8Ti7O27 ceramics has the best piezoelectric performance (d33 = 20.6 pC/N) in contrast to that of the undoped BaBi8Ti7O27 ceramics (d33 = 6.7 pC/N), which is substantially enhanced piezoelectric performance of the material by more than three times.

Gli stili APA, Harvard, Vancouver, ISO e altri

20

Abramov, Alexey N., Aleksei N. Gur'Yanov, Alexey S. Lobanov, Mikhail V. Yashkov, Alexander D. Plekhovich e A. M. Kut'In. "Obtaining and investigation of optical characteristics of fiber light guides with a core based on alumosilicate glass ceramics alloyed with chrome". Applied photonics 9, n. 1 (9 febbraio 2023): 54–72. http://dx.doi.org/10.15593/2411-4367/2022.1.03.

Testo completo

Abstract (sommario):

A technique has been developed for producing optical fibers doped with chromium ions based on chromium-doped aluminosilicate glass-ceramics. A technique is proposed for measuring luminescence spectra during the formation of a glass-ceramic core in Cr3+-activated aluminosilicate fibers.

Gli stili APA, Harvard, Vancouver, ISO e altri

21

Mandal, Soumen, Henry A. Bland, Jerome A. Cuenca, Malcolm Snowball e Oliver A. Williams. "Superconducting boron doped nanocrystalline diamond on boron nitride ceramics". Nanoscale 11, n. 21 (2019): 10266–72. http://dx.doi.org/10.1039/c9nr02729g.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Yoo, Ju-Hyun, e Yeong-Ho Jeong. "Microstructure and Piezoelectric Properties of 0.97(Na, K, Li)(Nb, Sb, Ta)O3-0.03(Bi, Na, Sr)ZrO3 Ceramics Doped with Boron Oxide for Piezoelectric Actuator". Journal of Nanoscience and Nanotechnology 21, n. 3 (1 marzo 2021): 2059–62. http://dx.doi.org/10.1166/jnn.2021.18898.

Testo completo

Abstract (sommario):

In this study, with the motivation of developing low temperature sintered Pb-free ceramics for use in piezoelectric actuators, 0.97(Na0.52K0.443Li0.037)(Nb0.923Sb0.04Ta0.037)O3 − 0.03 (Bi0.5Na0.5)0.9 (Sr)0.1ZrO3 ceramics were manufactured and their piezoelectric properties analyzed. All specimens doped with boron oxide showed a typical pure perovskite structure. The ceramics with x = 0.1 composition showed a co-existence of R-T phases. When boron oxide is doped at 0.1 wt%, excellent physical properties of d33 = 270 pC/N εr = 1386, kp = 0.416, and Qm = 130 were obtained making the ceramic ideal for use in piezoelectric actuators.

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Oliveira, M., S. Agathopoulos e J. M. F. Ferreira. "Reactions at the Interface Between Al2O3–SiO2 Ceramics with Additives of Alkaline-earth Oxides and Liquid Al–Si Alloy". Journal of Materials Research 17, n. 3 (marzo 2002): 641–47. http://dx.doi.org/10.1557/jmr.2002.0091.

Testo completo

Abstract (sommario):

The interfacial reactions between aluminosilicate ceramics doped with MgO, CaO, or BaO and Al–7 wt% Si alloy were investigated at 1023, 1173, and 1323 K under vacuum for 4 h. Alkaline-earth oxide additives defined phase formation and microstructure of the sintered ceramics and subsequently controlled the ceramic/metal interfacial reactions, which were always intensive. In general, reaction zones consisted of Al2O3, infiltrated with Al. In the case of CaO- and BaO-doped ceramics, precipitates formed into the metal phase and concentrated the reduced Ca and Ba, respectively. A reaction mechanism is proposed, which anticipates an active role of SiO2.

Gli stili APA, Harvard, Vancouver, ISO e altri

24

Liu, Chun Feng, Feng Ye e Yu Zhou. "In Situ Toughened α-Sialon Ceramics Doped with Lutecia and Ytterbia". Key Engineering Materials 353-358 (settembre 2007): 1525–28. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.1525.

Testo completo

Abstract (sommario):

Ytterbia and Lutecia were adopted to stabilize α-sialon ceramics during a two-step hot press sintering, respectively. Although Yb3+ and Lu3+ possess the similar small ion size (0.86 Å and 0.85 Å) as two adjacent rare-earth elements, Yb- and Lu-α-sialon ceramics present very different microstructure and properties. Yb-α-sialon ceramic is fully composed of α-sialon phase without any secondary phase. The ceramic incorporated with Lu2O3 also consists of α-sialon phase, but a trace amount of intergranular phase J′ (Lu4Si2-xAlxO7+xN2-x) still remains at the boundary. Microstructure observation indicates the fully equiaxial grain morphology of Yb-α-sialon ceramic. However, elongated grains appear in the Lu-α-sialon ceramic, coexisting with small equiaxed grains. Owing to the almost full α-sialon phase assemblage, both ceramics present high hardness with the value of over 21 GPa. Lu-α-sialon ceramic possesses good toughness, which is attributed to the elongated grains assisting the facilitation of toughening mechanism. The equiaxied grain morphology results in a comparatively lower toughness for Yb-α-sialon ceramic.

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Rai, Radheshyam, M. A. Valente, Anoop Kumar Shukla, Seema Sharma e Andrei L. Kholkin. "Dielectric and magnetic properties of Ba-, La- and Pb-doped Bi0.8Gd0.1M0.1Fe0.9Ti0.1O3 perovskite ceramics". Journal of Advanced Dielectrics 04, n. 02 (aprile 2014): 1450010. http://dx.doi.org/10.1142/s2010135x14500106.

Testo completo

Abstract (sommario):

The multiferroic Bi 0.8 Gd 0.1 M 0.1 Fe 0.9 Ti 0.1 O 3, (where M = Ba (DB), La (DL) and Pb (DP)) has been synthesized by using solid-state reaction technique. Effects of Ba , La and Pb substitution on the structure, electrical and ferroelectric properties of Bi 0.8 Gd 0.1 M 0.1 Fe 0.9 Ti 0.1 O 3 samples have been studied by performing X-ray diffraction, dielectric and magnetic measurements. The crystal structures of the ceramic samples have a tetragonal phase. The vibrating sample magnetometer (VSM) measurement shows a significant change in the magnetic properties of Ba -doped Bi 0.8 Gd 0.1 M 0.1 Fe 0.9 Ti 0.1 O 3 as compared to La - and Pb -doped ceramics. It is seen that coercive field (H C ) and remanent magnetization (M R ) increases with Ba -doped ceramics but decreases for La - and Pb -doped ceramics.

Gli stili APA, Harvard, Vancouver, ISO e altri

26

Li, Long Tu, Tian Wang, Xiao Hui Wang, Jing Chang Zhao e Xian Li. "Dielectric Characteristics of Doped Strontium Titanate within Broad Temperature Range". Key Engineering Materials 336-338 (aprile 2007): 158–60. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.158.

Testo completo

Abstract (sommario):

Dielectric characteristics of strontium titanate based ceramics doped with samarium were investigated within temperature range from –60oC to 150oC. XRD was used to identify the phase compositions of the ceramics and the microstructures were characterized by SEM. Good temperature coefficient of capacitance (TCC) was observed: TCC = +18% ~ −11% with high dielectric constant of 18000 and relative low dielectric loss. After further modification, the present ceramics might be promising candidates for the multilayer ceramic capacitors applications at high temperature.

Gli stili APA, Harvard, Vancouver, ISO e altri

27

Zhen, Yi Chao, Zhen Yong Cen, Wei Feng, Xiao Hui Wang e Long Tu Li. "High Piezoelectric Properties and High T_C in KNN-Based Lead-Free Ceramics Sintered in Reducing Atmosphere". Solid State Phenomena 281 (agosto 2018): 628–33. http://dx.doi.org/10.4028/www.scientific.net/ssp.281.628.

Testo completo

Abstract (sommario):

Lead-free MnO doped 0.955K0.5Na0.5NbO3-0.045Bi0.5Na0.5ZrO3(abbreviate as KNN-0.045BNZ) ceramics have been prepared by a conventional solid-state sintering method in a reducing atmosphere. The addition of MnO suppresses grain growth and eliminates the liquid phase. MnO dopant changes the crystalline structures of KNN-0.045BNZ ceramics from the classical Morphotropic Phase Boundary (MPB) with rhombohedral phase (R) and tetragonal phase (T) to the suppressed MPB with R/T phase. The 0.4% MnO doped KNN-0.045BNZ ceramics show an excellent electrical properties with quasi static piezoelectric constantd33=300 pC/N, Curie temperatureTC= 350 °C, insulation resistivity ρ=4.83 × 1011(Ω・cm), and high field piezoelectric constants =438 pm/V (atEmax= 25 kV/cm). The results indicate that the 0.4%Mn doped KNN-0.045BNZ ceramic is a promising lead-free piezoelectric candidate material for commercial applications.

Gli stili APA, Harvard, Vancouver, ISO e altri

28

Rai, Radheshyam, Poonam Kumari e M. A. Valente. "Study the structural and magnetic properties of rare-earth ions (La and Gd) doped Ba0.9575Ca0.0025Ti0.80685Mn0.002475Nb0.002475Zr0.1782O3 (BCTMNZ) ceramics". Journal of Advanced Dielectrics 05, n. 04 (dicembre 2015): 1520001. http://dx.doi.org/10.1142/s2010135x15200015.

Testo completo

Abstract (sommario):

In this paper, we investigated the influence of rare earth ([Formula: see text] and Gd) doped Ba[Formula: see text]RE[Formula: see text]Ca[Formula: see text]Ti[Formula: see text] Mn[Formula: see text]Nb[Formula: see text]Zr[Formula: see text]O3 (BCTMNZ) ceramics were fabricated by using a conventional solid-state reaction method. The doping effects of La and Gd on the structural and magnetic properties were studied. The structural pattern of the ceramic samples were investigated by X-ray diffraction and the results indicated that both samples shows an orthorhombic structure with pure phase. Strain and crystalline size values for Gd and La doped were 0.31–0.33% and [Formula: see text]–[Formula: see text]m, respectively. The room temperature hysteresis loops were obtained by using a vibrating sample magnetometer. La doped ceramic showed the higher value of magnetization i.e., [Formula: see text]B/f.u. as compared to Gd doped BLTMNZ ceramics.

Gli stili APA, Harvard, Vancouver, ISO e altri

29

Mitic, V. V., V. B. Pavlovic, L. Kocic, V. Paunovic e L. Zivkovic. "Fractal Geometry and Properties of Doped BaTiO₃ Ceramics". Advances in Science and Technology 67 (ottobre 2010): 42–48. http://dx.doi.org/10.4028/www.scientific.net/ast.67.42.

Testo completo

Abstract (sommario):

Taking into account that the complex grain structure is difficult to describe by using traditional analytical methods, in this study, in order to establish ceramic grain shapes of sintered BaTiO3, new approach on correlation between microstructure and properties of doped BaTiO3 ceramics based on fractal geometry has been developed. BaTiO3 ceramics doped with various dopants (MnCO3, Er2O3, Yb2O3) were prepared using conventional solid state procedure, and were sintered at 1350oC for four hours. The microstructure of sintered specimens was investigated by SEM-5300. Using method of fractal modeling a reconstruction of microstructure configurations, like grains shapes, or intergranular contacts has been successfully done. Furthermore, the area of grains surface was calculated using fractal correction that expresses the irregularity of grains surface through fractal dimension. The presented results, indicate that fractal method for ceramics structure analysis provides a new approach for describing, predicting and modeling the grain shape and relations between the BaTiO3-ceramic structure and dielectrical properties.

Gli stili APA, Harvard, Vancouver, ISO e altri

30

Li, Guo Rong, Sen Lin Leng, Liao Ying Zheng, Jiang Tao Zeng, Zhi Jun Xu e Rui Qing Chu. "Electrical Properties of Nb-Doped and Nb-Mn-Codoped BaTiO₃-(Bi_0.5Na_0.5)TiO₃ Lead-Free PTCR Ceramics". Advances in Science and Technology 67 (ottobre 2010): 134–42. http://dx.doi.org/10.4028/www.scientific.net/ast.67.134.

Testo completo

Abstract (sommario):

Nb-doped and Nb-Mn-codoped (1-xmol%)BaTiO3-xmol%(Bi0.5Na0.5)TiO3 (BBNTx) lead-free positive temperature coefficient of resistivity (PTCR) ceramics were prepared by the conventional solid state reaction method. The XRD patterns indicated that all BBNTx samples formed a single perovskite structure with tetragonal phase. 0.25 mol% Nb doped BBNT1 ceramic, sintered at 1330°C for 1h in air, had low room-temperature resistivity (ρ25) of 80 Ω•cm and a high resistivity jump (maximum resistivity [ρmax]/minimum resistivity [ρmin]) of 4.2 orders of magnitude with Tc about 152°C. The Nb-doped BBNTx (10≤x≤60) ceramics also showed distinct PTC effect with Tc between 185 and 232°C by sintering in N2, which was shut off when samples were cooled to a low temperature. In addition, The Nb-Mn-codoped BBNT1 ceramics exhibited higher resistivity jump than the single Nb-doped ones, with increasing the room-temperature resistivity.

Gli stili APA, Harvard, Vancouver, ISO e altri

31

Gu, Yong Jun, Jin Liang Huang, Xiang Ju Han, Qian Li, Xiao Wang e Hui Xu. "Effects of LiF on Sintering Temperature and Microwave Dielectric Properties of (Ca_0.3La_0.4/3)(Li_0.25Nd_0.25)TiO₃ Ceramics Doped by ZnO-B₂O₃- SiO₂ Glass". Materials Science Forum 675-677 (febbraio 2011): 155–58. http://dx.doi.org/10.4028/www.scientific.net/msf.675-677.155.

Testo completo

Abstract (sommario):

The sintering behaviors and microwave dielectric properties of the (Ca0.3La0.4/3)(Li0.25Nd0.25)TiO3 (abbreviated CLLNT) ceramics doped by small amounts of ZnOB2O3- SiO2 glass and LiF were investigated in this paper. The combination adding of ZnO-B2O3- SiO2 glass and LiF improved the densifications of the CLLNT ceramics and the sintering temperature of the CLLNT ceramics were efficiently lowered from 1400°C to 1000°C. Especially, the 4.0wt% ZnO-B2O3-SiO2 glass and 1.0wt% LiF doped CLLNT ceramic sintered at 1000°C for 3h has optimum microwave dielectric properties of Kr=97, Q×f=1286GHz, and TCF=43 ppm/°C, which enable it a suitable candidate for LTCC applications.

Gli stili APA, Harvard, Vancouver, ISO e altri

32

Deng, Yunfeng, Junjun Wang, Chunxiao Zhang, Hui Ma, Chungeng Bai, Danqing Liu, Fengmin Wu e Bin Yang. "Structural and Electric Properties of MnO2-Doped KNN-LT Lead-Free Piezoelectric Ceramics". Crystals 10, n. 8 (15 agosto 2020): 705. http://dx.doi.org/10.3390/cryst10080705.

Testo completo

Abstract (sommario):

Structural, ferroelectric, dielectric, and piezoelectric properties of K0.5Na0.5NbO3-LiTaO3-xmol%MnO2 lead-free piezoelectric ceramics with 0.0 ≤ x ≤ 0.3 were studied. The ceramic samples were synthesized through the conventional solid-state reaction method. The MnO2 addition can reduce the sintering temperature of KNLNT ceramics. Compared with undoped KNLNT ceramic, the piezoelectric measurements showed that piezoelectric properties of K0.5Na0.5NbO3-LiTaO3-xMnO2 were improved (d33 = 251 pC/N) when x = 0.1. In addition, KNLNT-xMnO2 ceramics have larger Pr(20.59~21.97 μC/cm2) and smaller Ec(10.77~6.95 kV/cm), which indicates MnO2 has excellent softening property, which improves the ferroelectric properties of KNLNT ceramics This work adds relevant information regarding of potassium sodium niobate K0.5Na0.5NbO3 (KNN) when doped Li, Ta, Mn at the B-site.

Gli stili APA, Harvard, Vancouver, ISO e altri

33

CHEN, QIAN, ZHIJUN XU, RUIQING CHU e YONG LIU. "DIELECTRIC AND FERROELECTRIC PROPERTIES OF (Li, Ce)-DOPED Sr2Bi4Ti5O18 LEAD-FREE CERAMICS". Journal of Advanced Dielectrics 01, n. 04 (ottobre 2011): 439–45. http://dx.doi.org/10.1142/s2010135x11000586.

Testo completo

Abstract (sommario):

The influence of (Li, Ce) doping on the electrical properties of bismuth layer Sr 2-x (Li, Ce) x/2 Bi4Ti5O18 [abbreviated to SBTi-(Li, Ce) X/2] ceramics was investigated. X-ray diffraction analysis showed that all the ceramic samples were single-phase compounds. The (Li, Ce) modification significantly decreased the dielectric loss of Sr2Bi4Ti5O18 ceramics and greatly improved the piezoelectric activity. At x/2 = 0.0125, the SBTi-(Li, Ce) x/2 ceramics exhibited the excellent properties with high remnant polarization (P r = 9.3 μC/cm2) and high Curie temperature (T c = 299°C). Meanwhile, the SBTi-(Li, Ce)0.0125 ceramics had the largest piezoelectric constant (d33 = 26 pC/N). The results showed that the SBTi-(Li, Ce) x/2 ceramic was a promising lead-free piezoelectric material.

Gli stili APA, Harvard, Vancouver, ISO e altri

34

Xiao, Zhuo Hao, Wen Yan Luo e Sheng Long Wang. "Thermal Expansion Property of P₂O₅ Doped Lithium Aluminosilicate Glass-Ceramic Synthesized by Sol-Gel Process". Materials Science Forum 663-665 (novembre 2010): 1281–84. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.1281.

Testo completo

Abstract (sommario):

Lithium aluminosilicate (LAS) glass-ceramics with 0 ~ 10 wt% phosphoric anhydride were prepared by sol-gel method and sintering at high temperature. Tetraethyl orthosilicate (TOES), aluminum nitrate, lithium carbonate were used as precursors. Differential thermal analysis (DTA), X-ray powder diffraction (XRD) and thermal expansion coefficient (TEC) were used to characterize the dried LAS gels and glass-ceramic blocks. The results suggest β-spodumene solid-solution is the only crystals phase in the P2O5 doped LAS glass-ceramics when sintering temperature is 950 oC. The thermal expansion coefficient of the P2O5 doped LAS glass-ceramics range from -0.1×10-6 oC-1 to 1.2×10-6 oC-1. Compared with the conventional melt quenching method, this process route provides a low temperature and timesaving method for preparing LAS glass-ceramics.

Gli stili APA, Harvard, Vancouver, ISO e altri

35

Zuo, Gui Hong, You Jin Zheng, Qiang Zhu, Yan Feng Liu, Chun Lei Wu, Li Ping Zhao, Si Nian Fu e Yan Ping Ma. "Effect of Additive Sm₂O₃ on Synthesizing AlN Ceramics at High Pressure". Advanced Materials Research 616-618 (dicembre 2012): 1860–63. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.1860.

Testo completo

Abstract (sommario):

In this paper, AlN ceramics doped with additive Sm2O3 has been synthesized by HPHT method. Furthermore, we have studied the impact of Sm2O3 on sintering AlN ceramic. The results show that the relative density of AlN ceramics increased at first, but decreased later with increasing Sm2O3. Compared with pressureless sintering, the time required to complete sintering AlN ceramic was shorter, and the sintering temperature was lower. And the growth model of AlN ceramics was pointed out and the proper explanation of its related phenomena were given in detail.

Gli stili APA, Harvard, Vancouver, ISO e altri

36

Hong, Yang, Jun Li, Han Bai, Zhenjia Song, Ming Wang e Zhongxiang Zhou. "Effect of octahedron tilt on the structure and magnetic properties of bismuth ferrite". Journal of Advanced Ceramics 9, n. 5 (25 settembre 2020): 641–46. http://dx.doi.org/10.1007/s40145-020-0398-1.

Testo completo

Abstract (sommario):

Abstract Multiferroic BiFeO3-based ceramics were synthesized using the rapid liquid-phase sintering method. The rare-earth ion (Sm3+, Gd3+, Y3+) doping causes structural distortion without changing the intrinsic rhombohedral perovskite structure. Raman analysis shows that the effect of doping on E modes is greater than A1 modes, and the microstructure of FeO6 octahedron can be regulated by ion doping. A-site trivalent ion doped ceramics exhibit improved magnetism compared with pure BiFeO3 ceramic, which originated from the suppressed spiral spin structure of Fe ions. The tilt of FeO6 octahedron as a typical structure instability causes the anomalous change of the imaginary part of permittivity at high frequency, and doped ceramics exhibit natural resonance around 16–17 GHz.

Gli stili APA, Harvard, Vancouver, ISO e altri

37

Lin, Ting, Ling Cong Fan, Zhi Bin Xu, Ying Shi, Jian Jun Xie, Lian Yun Deng e Yu Ying Ren. "Fabrication and Luminescent Properties of Translucent Ce³⁺:Lu₂SiO₅ Ceramics by Spark Plasma Sintering". Advanced Materials Research 295-297 (luglio 2011): 1300–1304. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.1300.

Testo completo

Abstract (sommario):

The spark plasma sintering (SPS) technique was employed to investigate the fabrication of cerium-doped lutetium orthosilicate (Ce:Lu2SiO5, LSO) polycrystalline scintillation ceramics starting from nanosized Ce:LSO powders synthesized by sol-gel processing. Fully-densed polycrystalline Ce:LSO ceramics with fine grains were fabricated on optimal sintering conditions of 1350°C for 5 min under pressure of 50 MPa. Translucent monolithic Ce:LSO ceramic sample was obtained with excellent luminescent characteristics after being annealed in air at 1000°C for 15 hrs. Under 360 nm UV excitation, a broad emission peak centered at 425 nm was detected for Ce:LSO ceramic, with a short decay time of only 9.67 ns. The luminescence intensity of annealed sample(doped by 0.5mol% Ce3+) is 3 times greater than that of BGO crystal under X-ray excitation. The good luminescent characteristics make Ce:LSO polycrystalline ceramics a promising scintillator candidate with high performance for radiation detection in future.

Gli stili APA, Harvard, Vancouver, ISO e altri

38

You, Qi, Hui Lin, Ruijin Hong, Zhaoxia Han, Dawei Zhang e Yuchong Ding. "Structural and Scintillation Properties of Ce3+:Gd3Al3Ga2O12 Translucent Ceramics Prepared by One-Step Sintering". Materials 16, n. 9 (25 aprile 2023): 3373. http://dx.doi.org/10.3390/ma16093373.

Testo completo

Abstract (sommario):

Cerium-doped gadolinium aluminum gallium garnet (Ce3+:Gd3Al3Ga2O12, Ce3+:GAGG) ceramic is a promising scintillation material. In this study, Ce3+:Gd3Al3Ga2O12 scintillation ceramics were prepared by the one-step sintering of commercially available Gd2O3, Al2O3, Ga2O3, and CeO2 powders in a flowing oxygen atmosphere at 1600 °C by solid-phase reaction sintering. For all the Ce3+:Gd3Al3Ga2O12 ceramic samples doped with different amounts of Ce3+ doping, dense ceramics were obtained. The structure, photoluminescence, and scintillation properties of the Ce3+:Gd3Al3Ga2O12 ceramics have been investigated. The average grain size of samples sintered at 1600 °C is about 2 μm. The X-ray excitation luminescence peak is around 560 nm, which is consistent with that of Ce3+:Gd3Al3Ga2O12 single crystals, matching well with the computed tomography X-ray detector’s response sensitivity. The light yield is higher compared to the standard reference sample—lutetium yttrium orthosilicate single crystal.

Gli stili APA, Harvard, Vancouver, ISO e altri

39

Albutt, Naphat, Suejit Pechprasarn, Sangwoei Sawekwiharee, Anchana Kuttiyawong, Panakamon Thonglor e Thanapong Sareein. "Complete Phase Change of Y₂NiMnO₆ Ceramics Doped with TiO₂ at High Temperature". Applied Mechanics and Materials 879 (marzo 2018): 47–50. http://dx.doi.org/10.4028/www.scientific.net/amm.879.47.

Testo completo

Abstract (sommario):

Determining the structure of ceramic materials is essential in order to fully characterize the electrical properties and improve existing materials. YMNO ceramics (Y2NiMnO6) prepared by compression and sintering were doped with TiO2 and analyzed using XRD and SEM. The calcined sample prior to sintering contained phases of the YMNO double perovskite and TiO2. Following sintering at 1400°C, the perovskite structure was replaced by Y2Ti2O7 fcc structure, and the grain size was found to increase with sintering time up to 18 hours. This sets a limit to the amount of TiO2 which can be used to successfully dope the YMNO ceramic.

Gli stili APA, Harvard, Vancouver, ISO e altri

40

Wang, Tian Guo, Qun Qin e Dong Jian Zhou. "Effect of Pr on the Microstructure and Electrical Properties of Ta-Doped TiO₂ Capacitor-Varistor Ceramics". Materials Science Forum 687 (giugno 2011): 34–38. http://dx.doi.org/10.4028/www.scientific.net/msf.687.34.

Testo completo

Abstract (sommario):

TiO2 varistors doped with 0.1 mol% Ta and different concentrations of Pr3+ were obtained by ceramic sintering processing at 1400 °C and their properties were characterized by XRD, SEM, I-V and impedance spectroscopy. The effect of Pr on the microstructure, nonlinear electrical behavior and dielectric properties of the Ta-doped TiO2 ceramics were investigated. It is found that Pr affects the grain size, electrical properties and the dielectric properties of the TiO2-based varistors. The samples have the nonlinear coefficients (α) values of (3.0-5.0) with low breakdown voltages (4-30 V/mm). A small quantities of Pr can improve the nonlinear properties of the samples significantly. It was found that an optimal doping composition of 0.5 mol% Pr3+ leads to a low breakdown voltage of 9.2 V/mm, a high nonlinear constant of 4.9 and an ultrahigh electrical permittivity of 8.38×104 (at 1 kHz), which is consistent with the highest grain boundary barriers of the ceramics. In view of these electrical characteristics, the TiO2-0.5 mol% Pr3+ceramic is a viable candidate for capacitor-varistor functional devices. The defects theory was introduced to explain the nonlinear electrical behavior of Pr-doped TiO2 ceramics.

Gli stili APA, Harvard, Vancouver, ISO e altri

41

Luo, Guo Qiang, J. Li, Dong Ming Zhang, Qiang Shen e Lian Meng Zhang. "Densification Mechanism of SnO2 Ceramics Doped with 5.0 mol% MnO2". Key Engineering Materials 351 (ottobre 2007): 88–92. http://dx.doi.org/10.4028/www.scientific.net/kem.351.88.

Testo completo

Abstract (sommario):

Dense SnO2 based ceramics are widely used. In this paper, 95SnO2-5MnO2 ceramics were prepared by pressureless sintering in air at different temperatures. Phase compositions and microstructures are examined by XRD, SEM and EDX, respectively. The SEM results show that different morphologies exist at the SnO2 grain boundary of ceramic, which compose of manganese oxidation, testified by EDX. The different manganese oxides phases, found by XRD, are the source of oxygen concentration at the grain boundary during heating and oxygen dissipation when cooling. However, solid solutions of Mn, Sn and O are not observed. The density of 95SnO2-5MnO2 ceramics decreases with increasing the sintering temperature, due to the evaporation of SnO and decreasing concentration of oxygen at grain boundary in the cooling process. Densification of the ceramic is promoted with inhibiting the decomposition of SnO2 by increasing oxygen concentration in the heating process, but it is limited by the dissipation of oxygen at the grain boundary in the cooling process.

Gli stili APA, Harvard, Vancouver, ISO e altri

42

Yang, Hao, Jian Zhang, Xian Peng Qin, De Wei Luo, Jan Ma, Ding Yuan Tang e Qi Tu Zhang. "Fabrication and Properties of High Quality Transparent Ho:YAG Ceramics". Solid State Phenomena 185 (febbraio 2012): 51–54. http://dx.doi.org/10.4028/www.scientific.net/ssp.185.51.

Testo completo

Abstract (sommario):

High quality holmium doped Yttrium Aluminum Garnet (YAG) transparent ceramics were fabricated by a reactive sintering method under vacuum. Fully dense Ho:YAG ceramics with the average grain size of ~ 10 μm were obtained after vacuum sintering at 1780 for 8 h. The optical properties, microstructures and photoluminescence spectra of the fabricated Ho:YAG ceramics were investigated. The transmittances of Ho:YAG ceramic are higher than 82% at 400 nm and 84% at 2400 nm. The absorption coefficient was 1.32 cm-1 for 1.5 at.% Ho:YAG at 1907 nm. And the absorption cross section of the Ho:YAG ceramic is 0.645×10-20 cm2.

Gli stili APA, Harvard, Vancouver, ISO e altri

43

Ismail, Mukhlis M. "Ferroelectric characteristics of Fe/Nb co-doped BaTiO3". Modern Physics Letters B 33, n. 22 (7 agosto 2019): 1950261. http://dx.doi.org/10.1142/s0217984919502610.

Testo completo

Abstract (sommario):

[Formula: see text] ceramics ([Formula: see text] mol.%, [Formula: see text]:[Formula: see text] = 1:3, 2:3, 3:2, 3:1) were successfully prepared using the traditional solid-phase sintering method. The effects of the proportion doping (Fe/Nb) components on various properties of BaTiO3 ceramics were studied. The X-ray diffraction showed that all solid solutions have the single cubic phase at room temperature, and that dielectric permittivity exhibits a maximum, Curie’s temperature at the peak. The ceramics have obvious peak shift effect: Curie’s temperature shifts to low temperature as Fe/Nb ratio increases. The high Fe/Nb ratio BaTiO3 ceramic showed also an enhancement of the broadening effect for dielectric constant curve with respect to temperature, and dielectric permittivity peak reflected phase transition from rhombohedral to tetragonal polar-nano regions. Dielectric and ferroelectric properties of Fe/Nb co-doped BaTiO3 ceramics have obvious enhanced ferroelectric properties and have slender hysteresis loop beneficial for energy storage materials.

Gli stili APA, Harvard, Vancouver, ISO e altri

44

Qiang, Liang Sheng, Dong Yan Tang, Xing Hong Zhang e L. Jin. "High-Speed Synthesis and Electric Properties of Magnesium Doped Lead Titanate Ceramics". Solid State Phenomena 121-123 (marzo 2007): 149–52. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.149.

Testo completo

Abstract (sommario):

By adding methyl alcohol/water solution with certain concentration into sol to hydrolysis directly and sintering the fresh sol directly, lead titanate(PbTiO3) ceramics doped with magnesium are prepared by using magnesium acetate as doper to prohibit the disadvantages contained in conventional sol-gel method, such as low hydrolytic rate, high sintering temperature, long preparation period. The changes of structure, microstructure, synthesis process and electric properties of modified ceramics are studied in detail. The sizes and morphology of high purely and high density magnesium doped lead titanate nanocrystals thus obtained are observed by TEM photographs and the structures and affection of sintering temperature of to lattice constant and sizes of nanocrystals are detected by XRD. Electric properties detection results show that doped lead titanate ceramics exhibite excellent dielectric, ferroelectric and pyroelectric properties compare with pure lead titanate.

Gli stili APA, Harvard, Vancouver, ISO e altri

45

Ri, Chol-Nam, Jong-Su Ri e Kwang-Ho Ju. "Influence of Sb2O3 doping on the sintering and polarization characteristics of PbTiO3 ceramic materials". Functional Materials Letters 14, n. 02 (febbraio 2021): 2150007. http://dx.doi.org/10.1142/s1793604721500077.

Testo completo

Abstract (sommario):

In this paper, the effect of Sb2O3 doping on the sintering and polarization stability of PbTiO3 ceramics was investigated. The Sb2O3-doped PbTiO3 ceramic materials were prepared viaa conventional piezoelectric ceramic processing. The results showed that the as-prepared PbTiO3 ceramics exhibit a good sintering stability without cracking during sintering because of reducing spontaneous strain stemmed from decrease the tetragonal degree of PbTiO3 by Sb2O3 doping. Furthermore, the polarization stability of Sb2O3-doped PbTiO3 ceramics was considerably enhanced by the relaxation of strain and stress concentration during poling stemmed from the formation of good microstructure with fine grain and high density, and by decreasing the loss stemmed from reduction of oxygen vacancy concentration due to the substitution of Sb[Formula: see text] ions for Ti[Formula: see text] ions under a polarization condition with temperature of 130–150[Formula: see text]C and applied electric field of 4.5–5.5 kV/mm, and its yield of polarization is achieved ca. 80%.

Gli stili APA, Harvard, Vancouver, ISO e altri

46

Qi, Jianquan, Zhilun Gui, Longtu Li e Yajing Wu. "Positive temperature coefficient resistance effect in Ba1-xSrxTiO3 ceramics modified with Bi2O3 and PbO by a vapor-doping method". Journal of Materials Research 14, n. 8 (agosto 1999): 3328–29. http://dx.doi.org/10.1557/jmr.1999.0450.

Testo completo

Abstract (sommario):

Ba1−xSrxTiO3-based positive temperature coefficient resistance (PTCR) ceramics were prepared by use of a vapor-doping method. When doped with Bi, the PTCR effect is improved; when doped with lead, however, the effect is weakened. The different influences of Bi and Pb doping on the ceramic properties are discussed in terms of the defect chemistry.

Gli stili APA, Harvard, Vancouver, ISO e altri

47

Yan, Zhong, Jin Liang Huang, Yong Jun Gu, Li Hua Li e Xiao Wang. "Effects of Doping ZnO-2B₂O₃-7SiO₂ Glass by Sol-Gel Method on BaO-Sm₂O₃-4TiO₂ Ceramics". Applied Mechanics and Materials 148-149 (dicembre 2011): 1077–80. http://dx.doi.org/10.4028/www.scientific.net/amm.148-149.1077.

Testo completo

Abstract (sommario):

BaO-Sm2O3-4TiO2 (abbreviated BST) ceramic powder was prepared by the conventional solid-state reaction method. The effects of doping ZnO-2B2O3-7SiO2 (abbreviated ZBS) glass by sol-gel method on the sintering behaviors, microstructure, phase composition and dielectric properties of BST ceramics were investigated. The experimental results reveal that the main phase of samples doped with ZBS glass is tungsten bronze structure type BaSm2Ti4O12 phase, a litter Sm2Ti2O7 phase is also observed. The sintering tenperature of BST ceramics is remarkably reduced from 1350°C to 1050°C and the good dielectric properties of εr=60.2，tanδ=0.004，τf=-7.9ppm/°C were obtained for BST ceramics doped with 6wt% ZBS glass by sol-gel method sintered at 1050°C for 3h.

Gli stili APA, Harvard, Vancouver, ISO e altri

48

Xu, Qiang, Wei Pan, Chun Lei Wan, Long Hao Qi, He Zhuo Miao e Fu Chi Wang. "A Promising LaSmZr₂O₇ Ceramic with Pyrochlore Structure for Thermal Barrier Coatings". Key Engineering Materials 368-372 (febbraio 2008): 1328–30. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1328.

Testo completo

Abstract (sommario):

Based on La2Zr2O7 ceramic for thermal barrier coatings, LaSmZr2O7 ceramic doped with samarium ion was successfully prepared using solid state reaction method. The pellets were sintered at 1600°C for 10 hours in air. The phase structure, thermal conductivity and thermal expansion coefficient of LaSmZr2O7 ceramic and La2Zr2O7 ceramic were measured by XRD, laser-flash device, high-temperature dilatometry, respectively. The results show that the crystal structure of LaSmZr2O7 ceramic is not affected by the doped samarium ion in the zirconium lattice. The thermophysical results show that the thermal conductivity of the LaSmZr2O7 ceramic is lower than that of La2Zr2O7 ceramic, while the thermal expansion coefficient is higher than that of La2Zr2O7 ceramic. These results indicate that LaSmZr2O7 ceramic or Ln2Zr2O7 ceramics doped with other rare earth ions could be candidate materials for future thermal barrier coatings.

Gli stili APA, Harvard, Vancouver, ISO e altri

49

Paunovic, Vesna, Vojislav Mitic, Miroslav Miljkovic, Vera Pavlovic e Ljiljana Zivkovic. "Ho2O3 additive effects on BaTiO3 ceramics microstructure and dielectric properties". Science of Sintering 44, n. 2 (2012): 223–33. http://dx.doi.org/10.2298/sos1202223p.

Testo completo

Abstract (sommario):

Doped BaTiO3-ceramics is very interesting for their application as PTCR resistors, multilayer ceramic capacitors, thermal sensors etc. Ho doped BaTiO3 ceramics, with different Ho2O3 content, ranging from 0.01 to 1.0 wt% Ho, were investigated regarding their microstructural and dielectric characteristics. The samples were prepared by the conventional solid state reaction and sintered at 1320? and 1380?C in an air atmosphere for 4 hours. The grain size and microstructure characteristics for various samples and their phase composition was carried out using a scanning electron microscope (SEM) equipped with EDS system. SEM analysis of Ho/BaTiO3 doped ceramics showed that in samples doped with a rare-earth ions low level, the grain size ranged from 20-30?m, while with the higher dopant concentration the abnormal grain growth is inhibited and the grain size ranged between 2- 10?m. Dielectric measurements were carried out as a function of temperature up to 180?C. The low doped samples sintered at 1380?C, display the high value of dielectric permittivity at room temperature, 2400 for 0.01Ho/BaTiO3. A nearly flat permittivity-response was obtained in specimens with higher additive content. Using a Curie-Weiss low and modified Curie-Weiss low the Curie constant (C), Curie temperature (Tc) and a critical exponent of nonlinearity (?) were calculated. The obtained value of ? pointed out that the specimens have almost sharp phase transition.

Gli stili APA, Harvard, Vancouver, ISO e altri

50

Özer, Ummuhanı Hilal, Kerim Emre Öksüz e Ali Özer. "Synthesis and Characterization of CeO₂ Doped ZrO₂ Ceramics by a Simple Sol-Gel Route". Materials Science Forum 907 (settembre 2017): 56–60. http://dx.doi.org/10.4028/www.scientific.net/msf.907.56.

Testo completo

Abstract (sommario):

It is well known that sol-gel technique is a simple method to produce nano sized ceramic powders. In this study, cerium oxide doped zirconia samples, with 10 mol%-12mol% and14mol% CeO2, were synthesized by sol-gel technique and characterized. The surface morphology, elemental composition, microstructure, and phase analysis, of the sintered CeO2 doped ZrO2 ceramics were characterized by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDS) analysis, and X-ray diffraction (XRD) respectively. X-ray diffraction for samples sintered at 1550 °C for 4h revealed that the zirconia ceramics have a tetragonal phase structure. The addition of CeO2 can raise the content of the tetragonal phase, but the minor monoclinic phase exists even at the CeO2 content of 10 mol%. The effect of dopant concentration on the lattice parameter, average primary crystallite size and micro-strain was studied. Relative densities for CeO2 doped ZrO2 bulk ceramics varied between 95% and 99 %, depending on the CeO2 addition.

Gli stili APA, Harvard, Vancouver, ISO e altri

Articoli di riviste sul tema "CERAMICS DOPED"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili