Статті в журналах: "Spark Plasma Sintering (SPS)"

1

Muhammad, Wan Nur Azrina Wan, Yoshiharu Mutoh, and Yukio Miyashita. "Microstructure and Mechanical Properties of Magnesium Prepared by Spark Plasma Sintering." Advanced Materials Research 129-131 (August 2010): 764–68. http://dx.doi.org/10.4028/www.scientific.net/amr.129-131.764.

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Magnesium powders were sintered by using spark plasma sintering (SPS) and conventional pressureless sintering (PLS) techniques at sintering temperatures ranged from 552°C to 605°C to investigate effect of sintering method on microstructure and mechanical properties of sintered magnesium. High densed magnesium could be obtained by using spark plasma sintering technique compared to conventional presureless sintering at the same sintering temperature. It was found that the ultimate tensile strength increased with increasing sintering temperature for both the materials sintered by PLS and SPS. The magnesium samples prepared by SPS showed better mechanical properties than those prepared by PLS. The microstructural observations revealed that the grain growth was not significant in SPS process compared to PLS, which would enhance the mechanical properties of the SPS sintered magnesium.

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2

Nisar, Ambreen, Cheng Zhang, Benjamin Boesl, and Arvind Agarwal. "Unconventional Materials Processing Using Spark Plasma Sintering." Ceramics 4, no. 1 (January 8, 2021): 20–39. http://dx.doi.org/10.3390/ceramics4010003.

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Spark plasma sintering (SPS) has gained recognition in the last 20 years for its rapid densification of hard-to-sinter conventional and advanced materials, including metals, ceramics, polymers, and composites. Herein, we describe the unconventional usages of the SPS technique developed in the field. The potential of various new modifications in the SPS technique, from pressureless to the integration of a novel gas quenching system to extrusion, has led to SPS’ evolution into a completely new manufacturing tool. The SPS technique’s modifications have broadened its usability from merely a densification tool to the fabrication of complex-shaped components, advanced functional materials, functionally gradient materials, interconnected materials, and porous filter materials for real-life applications. The broader application achieved by modification of the SPS technique can provide an alternative to conventional powder metallurgy methods as a scalable manufacturing process. The future challenges and opportunities in this emerging research field have also been identified and presented.

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3

Nisar, Ambreen, Cheng Zhang, Benjamin Boesl, and Arvind Agarwal. "Unconventional Materials Processing Using Spark Plasma Sintering." Ceramics 4, no. 1 (January 8, 2021): 20–40. http://dx.doi.org/10.3390/ceramics4010003.

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Анотація:

Spark plasma sintering (SPS) has gained recognition in the last 20 years for its rapid densification of hard-to-sinter conventional and advanced materials, including metals, ceramics, polymers, and composites. Herein, we describe the unconventional usages of the SPS technique developed in the field. The potential of various new modifications in the SPS technique, from pressureless to the integration of a novel gas quenching system to extrusion, has led to SPS’ evolution into a completely new manufacturing tool. The SPS technique’s modifications have broadened its usability from merely a densification tool to the fabrication of complex-shaped components, advanced functional materials, functionally gradient materials, interconnected materials, and porous filter materials for real-life applications. The broader application achieved by modification of the SPS technique can provide an alternative to conventional powder metallurgy methods as a scalable manufacturing process. The future challenges and opportunities in this emerging research field have also been identified and presented.

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4

Drouet, Christophe, C. Largeot, G. Raimbeaux, Claude Estournès, Gérard Dechambre, Christèle Combes, and Christian Rey. "Bioceramics: Spark Plasma Sintering (SPS) of Calcium Phosphates." Advances in Science and Technology 49 (October 2006): 45–50. http://dx.doi.org/10.4028/www.scientific.net/ast.49.45.

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Calcium phosphates (Ca-P) are major constituents of calcified tissues, and are also extensively used for the elaboration of biomaterials. However, the usual high-temperature sintering processes generally lead to strong alterations of their chemical, physical and biological properties. Spark plasma sintering (SPS) is a non-conventional sintering technique based on the use of pulsed current, enabling fast heating and cooling rates, and lower sintering temperatures are often observed. The sintering of several orthophosphates (DCPD, amorphous TCP, beta-TCP, OCP, HA and biomimetic nanocrystalline apatites) by SPS was investigated in order to track potential advantages of this technique over usual Ca-P sintering methods. Special attention was given to the SPS consolidation of highly bioactive nanocrystalline apatites.

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5

Olevsky, Eugene, S. Kandukuri, and Ludo Froyen. "Analysis of Mechanisms of Spark-Plasma Sintering." Key Engineering Materials 368-372 (February 2008): 1580–84. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1580.

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Spark-Plasma Sintering (SPS) involves rapid heating of powder by electric current with simultaneous application of external pressure. Numerous experimental investigations point to the ability of SPS to render highly-dense powder products with the potential of grain size retention. The latter ability is of significance for the consolidation of nano-powder materials where the grain growth is one of the major problems. A model for spark-plasma sintering taking into consideration various mechanisms of material transport is developed. The results of modeling agree satisfactorily with the experimental data in terms of SPS shrinkage kinetics.

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6

Sebayang, Darwin, Deni S. Khaerudini, Hendi Saryanto, M. A. Othman, Mat Husin Saleh, D. Fredrick, and Pudji Untoro. "Microstructure and Mechanical Properties of Nanocrystalline FeCr Alloy Prepared by Spark Plasma Sintering." Applied Mechanics and Materials 52-54 (March 2011): 2197–202. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.2197.

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This paper investigates the efficiency of two consolidation processing techniques prepared by spark plasma sintering (SPS) and hot pressing (HP) which allow obtaining fully dense nanostructured materials. FeCr powders were sintered by using spark plasma sintering (SPS) and hot pressing (HP) sintering techniques over sintering temperature up to 1000oC. The microstructures of the sintered end-products were characterized by Scanning Electron Microscopy (SEM). X-rays diffraction line profile analysis was adopted to analyze the crystallite size of starting and sintered FeCr using Williamson–Hall method. The density of the sintered specimens was measured by using the Archimedes method. The result indicated that the dense specimen with relative similar density and approaching the equilibrium state obtained in shorter time and lower sintering temperature by spark plasma sintering compared to conventional hot pressing. The FeCr specimen prepared by SPS showed more effective to retain nanocrystalline and better mechanical properties than those prepared by HP. The diffraction investigation revealed that the grain growth was not significant in SPS process compared to HP, which would enhance the mechanical properties of the SPS sintered FeCr.

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7

Huang, Qing, Yong Huang, Chang An Wang, and Hou Xing Zhang. "Fabrication Processes and Properties of Highly Pure MgAlON Materials." Materials Science Forum 561-565 (October 2007): 543–46. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.543.

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In this paper, the MgAlON ceramic was fabricated by Spark Plasma Sintering (SPS) and hot press sintering respectively. The results showed that highly pure and single-phase MgAlON could be fabricated at lower sintering temperature in a short period through SPS process, compared with the conventional Hot Press sintering (HP) process. The bending strength of MgAlON specimens prepared by SPS process was higher than 500MPa while bending strength of HP specimens was much lower. The open porosity was almost eliminated in SPS MgAlON specimens. Spark Plasma Sintered MgAlON had a single phase of MgAlON while Hot Press Sintered MgAlON had major MgAlON and minor AlN and Al2O3.

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8

Fang, Ming Hao, Wei Pan, Sui Lin Shi, and Zhen Yi Fang. "Kinetics Model for the Initial Stage of Spark Plasma Sintering." Key Engineering Materials 336-338 (April 2007): 2366–68. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.2366.

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The sintering kinetics model of initial stage by spark plasma sintering (SPS) is discussed in this paper. During SPS, there are discharges among the powder particles. And the particles surface will be melted and form viscose flow. These phenomena accelerate the particles rearrangement and reduce the sintering time. The relationship between the shrinkage ratio of particles and the sintering time during the initial stages of sintering by SPS has been obtained. The results show that L/L0 is linear to the time.

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9

Lee, Ji-Sun, Chae-Myung Chang, Young IL Lee, Jong-Heun Lee, and Seong-Hyeon Hong. "Spark Plasma Sintering (SPS) of NASICON Ceramics." Journal of the American Ceramic Society 87, no. 2 (February 2004): 305–7. http://dx.doi.org/10.1111/j.1551-2916.2004.00305.x.

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10

Dudina, Dina, Boris Bokhonov, and Eugene Olevsky. "Fabrication of Porous Materials by Spark Plasma Sintering: A Review." Materials 12, no. 3 (February 12, 2019): 541. http://dx.doi.org/10.3390/ma12030541.

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Spark plasma sintering (SPS), a sintering method that uses the action of pulsed direct current and pressure, has received a lot of attention due to its capability of exerting control over the microstructure of the sintered material and flexibility in terms of the heating rate and heating mode. Historically, SPS was developed in search of ways to preserve a fine-grained structure of the sintered material while eliminating porosity and reaching a high relative density. These goals have, therefore, been pursued in the majority of studies on the behavior of materials during SPS. Recently, the potential of SPS for the fabrication of porous materials has been recognized. This article is the first review to focus on the achievements in this area. The major approaches to the formation of porous materials by SPS are described: partial densification of powders (under low pressures, in pressureless sintering processes or at low temperatures), sintering of hollow particles/spheres, sintering of porous particles, and sintering with removable space holders or pore formers. In the case of conductive materials processed by SPS using the first approach, the formation of inter-particle contacts may be associated with local melting and non-conventional mechanisms of mass transfer. Studies of the morphology and microstructure of the inter-particle contacts as well as modeling of the processes occurring at the inter-particle contacts help gain insights into the physics of the initial stage of SPS. For pre-consolidated specimens, an SPS device can be used as a furnace to heat the materials at a high rate, which can also be beneficial for controlling the formation of porous structures. In sintering with space holders, SPS processing allows controlling the structure of the pore walls. In this article, using the literature data and our own research results, we have discussed the formation and structure of porous metals, intermetallics, ceramics, and carbon materials obtained by SPS.

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11

Schaefer, Daniel Auri, Leandro da Conceição, Marcos Antonio Coelho Berton, Luiz Carlos Ferracin, and Nério Vicente Jr. "Spark Plasma Sintering of Low Alloy Steel Powder." Materials Science Forum 899 (July 2017): 483–86. http://dx.doi.org/10.4028/www.scientific.net/msf.899.483.

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Spark Plasma Sintering (SPS) process is a relatively new PM technology used to fabricate metallic parts in shorter time and lower temperature than traditional press-to-sintering technology. In this study, sintering cycles by SPS process were performed in Astaloy CrM steel powder at temperatures between 950 and 1100 °C, with 5 minutes of dwell time and under 60 MPa of uniaxial compaction pressure. The apparent density measured by Archimedes principle, the microstructural investigation by optical microscopy (OM) and scanning electron microscopy (SEM) and the hardness tests by Vicker’s indentation were carried out with the sintered samples. It was observed that at 1050°C more than 98 % of densification was attained. As a low alloy steel powder sintered by SPS an expected high level of densification by the solid state sintering was achieved while hardness is lower than that expected for the Astaloy CrM when sintered mixed with graphite particles.

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12

Kim, Ji Soon, Young Do Kim, Choong Hyo Lee, Pyuck Pa Choi, and Young Soon Kwon. "Spark-Plasma Sintering of Molybdenum Disilicide." Key Engineering Materials 287 (June 2005): 160–65. http://dx.doi.org/10.4028/www.scientific.net/kem.287.160.

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The effect of milling on the densification behavior of MoSi2 powder during spark-plasma sintering (SPS) was investigated. MoSi2 starting powder with an average particle size of 10 µm was milled to reduce particle sizes to less than 1 µm. Sintering was performed in a SPS facility, varying the sintering temperature from 1200°C to 1500°C. Changes in relative density and the densification rate were measured as a function of temperature. Additionally, the microstructure of sintered compacts was analyzed by means of SEM and EPMA. The sintered density was lower for ballmilled powder compacts (having 94-95% relative density) than for as-received ones (having 94- 98% relative density) despite a higher densification rate of the former in the early and middle stages of sintering. These apparently contradictory results can be explained by a pick-up of oxygen (from 0.3 to 1.8 wt. % O) during the milling process, leading to the formation of silicon oxide and its decomposition into a gas phase at temperatures above 1200°C.

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13

Zhao, Yingying, Xiao Liu, Xiaoyu Zhang, and Huiling Du. "Enhanced Energy Storage Properties of La-Doped Sr0.6Ba0.4Nb2O6 Relaxor Ferroelectric Ceramics Prepared by Spark Plasma Sintering." Materials 15, no. 12 (June 20, 2022): 4360. http://dx.doi.org/10.3390/ma15124360.

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In this work, La-doped Sr0.6Ba0.4Nb2O6 ferroelectric ceramics were fabricated by the conventional solid state reaction method (CS) and spark plasma sintering (SPS), respectively. The microstructure, phase structure, dielectric properties, relaxor behavior, ferroelectric and energy storage properties were investigated and compared to indicate the effects of spark plasma sintering on their performances. The results show that the grain shape changes from columnar to isometric crystal and the grain size decreases obviously after spark plasma sintering. The dielectric constant of the CS sample and the SPS sample both show a typical relaxor behavior with obvious frequency dispersion. The diffusion parameters (γ) of both CS sample and SPS sample are close to 2 and all the samples present slim polarization–electric (P-E) loops, which verify the relaxor behavior. Moreover, the breakdown strength, Eb, and discharge energy storage density, Wrec, of La-doped Sr0.6Ba0.4Nb2O6 ferroelectric ceramics prepared by SPS are improved significantly. This work provides guidance for improving the energy storage performance of ferroelectric ceramics with tungsten bronze structures by decreasing the grain size through adopting a different sintering method.

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14

Brankovic, Zorica, Danijela Lukovic-Golic, Aleksandar Radojkovic, Jovana Cirkovic, Damir Pajic, Zorica Marinkovic-Stanojevic, Junwei Xing, Miladin Radovic, Guorong Li, and Goran Brankovic. "Spark plasma sintering of hydrothermally synthesized bismuth ferrite." Processing and Application of Ceramics 10, no. 4 (2016): 257–64. http://dx.doi.org/10.2298/pac1604257b.

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Bismuth ferrite, BiFeO3 (BFO), powder was synthesized by hydrothermal method from Bi(NO3)3?5H2O and Fe(NO3)3?9H2O as precursors. The synthesized powder was further sintered using spark plasma sintering (SPS). The sintering conditions were optimized in order to achieve high density, minimal amount of secondary phases and improved ferroelectric andmagnetic properties. The optimal structure and properties were achieved after spark plasma sintering at 630?C for 20min, under uniaxial pressure of 90MPa. The composition, microstructure, ferroelectric and magnetic properties of the SPS samples were characterized and compared to those of conventionally sintered ceramics obtained from the same powder. Although the samples sintered using conventional method showed slightly lower amount of secondary phases, the spark plasma sintered samples exhibited favourable microstructure and better ferroelectric properties.

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15

Chen, Biyang, Zhiguo Peng, Tengfei Tang, Gao Yue, and Weijia Zhang. "Research and improvement of SPS spark plasma sintering equipment." Journal of Physics: Conference Series 2483, no. 1 (May 1, 2023): 012039. http://dx.doi.org/10.1088/1742-6596/2483/1/012039.

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Abstract Through the functional disassembly study of the pressurization system, vacuum and atmosphere control system, water cooling system and control system of the SPS spark plasma equipment, the problems in the actual production process and the corresponding improvements of the spark plasma sintering (SPS) equipment are also discussed. The shortcomings and its development directions are also proposed to provide sufficient data support for the subsequent research.

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16

Ognev, Alexey, Alexander S. Samardak, Vladimir Pechnikov, and Evgeniy Papynov. "SPS Temperature Influence on the Composition, Structure and Magnetic Properties of Hematite Ceramics." Materials Science Forum 1045 (September 6, 2021): 102–8. http://dx.doi.org/10.4028/www.scientific.net/msf.1045.102.

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Spark Plasma Sintering (SPS), also known as pulsed electric current sintering (PECS) or field assisted sintering technology (FAST), belongs to a class of powder metallurgy methods. Investigations of the effect of thermal, electric and electromagnetic fields arising under the conditions of spark plasma sintering of ceramic materials on their final characteristics are of important fundamental scientific significance. In this regard, the work investigated the effect of the IPA temperature on the structure, composition and magnetic properties of hematite α-Fe2O3 of high purity 99.995%. Changes in the structure and composition of ceramic specimens under SPS conditions in the temperature range 800-1000°C are described by scanning electron microscopy and X-ray phase analysis. The magnetic properties are studied and the regularities of changes of the magnetization (Ms) and coercive force (Hc) under the influence of an external magnetic field for ceramic samples are determined depending on the temperature of the SPS. These results can be considered as initial study of the process of consolidation of materials with weak ferromagnetism under conditions of spark plasma sintering.

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17

Yamaguchi, N., H. Tanaka, and Osamu Ohashi. "Gas Analysis in Spark Plasma Sintering of Hydroxyapatite." Materials Science Forum 449-452 (March 2004): 793–96. http://dx.doi.org/10.4028/www.scientific.net/msf.449-452.793.

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In this paper, the effect of electric current on sintering of hydroxyapatite (HAp) in spark plasma sintering (SPS) process was investigated. The carbonate partially substituting hydroxyapatite was sintered up to 900 °C, and CO2 evolved from HAp powder were measured in situ by using mass spectroscopy apparatus in the same time. The same gas analysis was performed in thermal analysis as comparison. In the thermal analysis, CO2 gas was evolved at about 600 °C. On the other hand, in the SPS process, CO2 gas was detected at lower temperature than that of thermal analysis. This result indicates that the surface of hydroxyapatite particles would be heated up locally in SPS process due to electric current.

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18

Kawagoe, Daisuke, Yoshihiro Koga, Noriko Kotobuki, Hajime Ohgushi, Emile Hideki Ishida, and Koji Ioku. "Densification Behavior of Calcium Phosphates on Spark Plasma Sintering." Key Engineering Materials 309-311 (May 2006): 171–74. http://dx.doi.org/10.4028/www.scientific.net/kem.309-311.171.

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Ceramics of hydroxyapatite (Ca10(PO4)6(OH)2: HA) and β-tricalcium phosphate (β-Ca3(PO4)2: β-TCP), were prepared by spark plasma sintering (SPS) at the temperatures from 800 °C to 1000 °C for 10 min with a heating rate of 25 °C·min-1. The HA ceramics prepared at 900 °C and 1000 °C showed transparency. On the other hands, transparent β-TCP ceramics was obtained by SPS at 1000 °C. In analysis of the densification behavior during sintering of HA and β-TCP by SPS, dominant sintering mechanism was plastic flow in the early stage of densification. Transparent ceramics should be the most suitable materilas to investigate the interface between human cells and ceramics.

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19

Campos, M. Alberteris, N. Vicente, I. F. Machado, K. S. T. de Souza, D. Rodrigues, and Marcos F. de Campos. "NdFeB Type Magnets Produced by Spark Plasma Sintering." Materials Science Forum 802 (December 2014): 585–89. http://dx.doi.org/10.4028/www.scientific.net/msf.802.585.

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The shortage of dysprosium as an alloying element has directed the research on the grain size refining of NdFeB, since higher coercivities can be obtained by decreasing the grain size, without Dy addition. The Spark Plasma Sintering (SPS) is a consolidation process which allows densification at lower temperatures and shorter dwell times of sintering, thus avoiding the grain growth. Therefore, the typical temperature of sintering of NdFeB magnets can be decreased from 1050°C to around 800°C, as it was evidenced by means of SPS shrinkage curves and the high densified microestructure obtained in this work.

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20

Wang, S. W., L. D. Chen, and T. Hirai. "Densification of Al2O3 Powder Using Spark Plasma Sintering." Journal of Materials Research 15, no. 4 (April 2000): 982–87. http://dx.doi.org/10.1557/jmr.2000.0140.

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Al2O3 powders with four different particle sizes were densified using a spark plasma sintering (SPS) apparatus under three different sintering conditions: holding time, heating rate, and mechanical pressure. The Al2O3 powder compact sintered at a higher heating rate produced a sample with a higher density and a fine-grained microstructure, while abnormal grain growth and a lower density resulted when a lower heating rate was applied, though the sintering temperature and holding time were the same in both cases. This revealed that rapid sintering by SPS was effective for promoting the densification of the powder. However, the powder with a coarse particle size was hard to sinter at a higher heating rate. Microstructural observation revealed that the edge part was denser than the inside of the sample when the holding time was short. Increasing the holding time made it possible for the inside to be sintered almost as dense as the edge part. Mechanical pressure was found to enhance densification of the Al2O3 powder. On the basis of these results, the SPS process is discussed.

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21

Zhang, Rui, Hai Long Wang, Ling Xin, and Hong Liang Xu. "Pressure Sensitivity of SiC/Cu Composites Prepared by SPS." Key Engineering Materials 336-338 (April 2007): 2353–56. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.2353.

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SiC/Cu composites were prepared by spark plasma sintering under different uniaxial pressure. X-ray diffraction (XRD), SEM techniques were used to characterize the sintered samples. It was found that higher pressure led to the transformation of Cu into Cu2O. The microhardness of the composites was improved by SiC reinforcements. The optimised pressure during the spark plasma sintering was about 50 MPa with the maximum hardness of 1.36 GPa.

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22

Laszkiewicz-Łukasik, Jolanta, Piotr Putyra, Piotr Klimczyk, Marcin Podsiadło, and Kinga Bednarczyk. "Spark Plasma Sintering/Field Assisted Sintering Technique as a Universal Method for the Synthesis, Densification and Bonding Processes for Metal, Ceramic and Composite Materials." Journal of Applied Materials Engineering 60, no. 2 (January 28, 2021): 53–69. http://dx.doi.org/10.35995/jame60020005.

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This paper presents the technology of powder sintering by the spark plasma sintering method, also known as the field assisted sintering technique. The mechanisms, compared to other sintering techniques, advantages of this system, applied modifications and the history of the development of this technique are presented. Spark Plasma Sintering (SPS) uses uniaxial pressing and pulses of electric current. The direct flow of current through the sintered material allows high heating rates to be reached. This has a positive effect on material compaction and prevents the grain growth of sintered compact. The SPS mechanism is based on high-energy spark discharges. A low-voltage current pulse increases the kinetics of diffusion processes. The SPS temperature is up to 500 °C lower than the sintering temperature using conventional methods. The phenomena that occur during sintering with the Field Assisted Sintering Technology (FAST)/SPS method give great results for consolidating all types of materials, including those which are nonconductive. This method is used, among others, in relation to metals, alloys and ceramics, including advanced and ultra-high-temperature ceramics. Due to the good results and universality of this method, in recent years it has been developed and often used in research institutions, but also in industry.

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23

Kruzel, Robert, Tomasz Dembiczak, and Joanna Wachowicz. "Optimization of Spark Plasma Sintering Technology by Taguchi Method in the Production of a Wide Range of Materials: Review." Materials 16, no. 16 (August 9, 2023): 5539. http://dx.doi.org/10.3390/ma16165539.

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This paper reviews the production of sinters using the spark plasma sintering method. SPS (spark plasma sintering) technology has been used for several decades, mainly in laboratories, to consolidate a huge number of both new and traditional materials. However, it is now more often introduced into practical industrial use, with equipment as early as the fifth generation capable of producing larger-size components at competitive costs. Although the mechanism of sintering with the use of this method is not yet understood, the effectiveness of the SPS process for the rapid and efficient consolidation of a wide range of materials with novel micro-structures remains indisputable. With a relatively wide variation in chemical composition, the structure allows the selection of appropriate consolidation parameters for these materials. The influence on the values of apparent density and mechanical properties depends on the parameters of the spark plasma sintering process. In order to achieve a density close to the theoretical density of sinters, optimization of the sintering parameters, i.e., sintering temperature, heating rate, sintering time, pressing pressure and protective atmosphere, should be carried out. In this paper, the optimization of spark plasma sintering of Si3N4–Al2O3–ZrO2 composite was carried out using the Taguchi method. The effects of four sintering factors, namely heating rate, sintering time, sintering temperature and sintering pressure, on the final density were investigated. Optimal sintering conditions were proposed and a confirmation experiment was conducted. The optimal combination of sintering conditions for spark plasma sintering (SPS) of Si3N4–Al2O3–ZrO2 composite for high apparent density was determined as A3-B3-C3-D2. Based on ANOVA analysis, it was found that the apparent density of sintering was significantly influenced by sintering temperature, followed by pressing pressure, sintering time and heating rate. Validation of the developed mathematical model predicting the apparent density of sinters showed close agreement between the predicted response results and experimental results.

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24

Manière, Charles, Elisa Torresani, and Eugene Olevsky. "Simultaneous Spark Plasma Sintering of Multiple Complex Shapes." Materials 12, no. 4 (February 13, 2019): 557. http://dx.doi.org/10.3390/ma12040557.

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This work addresses the two great challenges of the spark plasma sintering (SPS) process: The sintering of complex shapes and the simultaneous production of multiple parts. A new controllable interface method is employed to concurrently consolidate two nickel gear shapes by SPS. A graphite deformable sub-mold is specifically designed for the mutual densification of both complex parts in a unique 40 mm powder deformation space. An energy efficient SPS configuration is developed to allow the sintering of a large-scale powder assembly under electric current lower than 900 A. The stability of the developed process is studied by electro-thermal-mechanical (ETM) simulation. The ETM simulation reveals that homogeneous densification conditions can be attained by inserting an alumina powder at the sample/punches interfaces, enabling the energy efficient heating and the thermal confinement of the nickel powder. Finally, the feasibility of the fabrication of the two near net shape gears with a very homogeneous microstructure is demonstrated.

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25

Shevtsova, Lilia I., Michail A. Korchagin, Alexander Thömmes, Vyacheslav I. Mali, Alexander G. Anisimov, and Sergey Yu Nagavkin. "Spark Plasma Sintering of Mechanically Activated Ni and Al Powders." Advanced Materials Research 1040 (September 2014): 772–77. http://dx.doi.org/10.4028/www.scientific.net/amr.1040.772.

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In this paper structure and mechanical properties of Ni3Al intermetallic compound was studied. The materials was fabricated according to different schemes, which combined mechanical alloying of Ni and Al powders, self-propagating high temperature synthesis (SHS) and spark plasma sintering (SPS). Relative density of all sintered samples was ~ 97 %. Microhardness of the sintered materials ranged from 6100 to 6300 MPa. SPS of 86.71 % wt. Ni and 13.29 % wt. Ni powder at 1100 °C led to formation of material with the highest level of tensile strength equal to 400 MPa.

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Ghahremani, D., T. Ebadzadeh, and A. Maghsodipour. "Spark plasma sintering of mullite: Relation between microstructure, properties and spark plasma sintering (SPS) parameters." Ceramics International 41, no. 5 (June 2015): 6409–16. http://dx.doi.org/10.1016/j.ceramint.2015.01.078.

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Stuer, Michael, Paul Bowen, and Zhe Zhao. "Spark Plasma Sintering of Ceramics: From Modeling to Practice." Ceramics 3, no. 4 (November 17, 2020): 476–93. http://dx.doi.org/10.3390/ceramics3040039.

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Summarizing the work of nearly a decade of research on spark plasma sintering (SPS), a review is given on the specificities and key factors to be considered in SPS of ceramic materials, based on the authors’ own research. Alumina is used primarily as a model material throughout the review. Intrinsic inhomogeneities linked to SPS and operational parameters, which depend on the generation of atomistic scale defects, are discussed in detail to explain regularly observed inhomogeneities reported in literature. Adopting an engineering approach to overcome these inherent issues, a successful processing path is laid out towards the mastering of SPS in a wide range of research and industrial settings.

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Ricote, S., G. Caboche, C. Estournes та N. Bonanos. "Synthesis, Sintering, and Electrical Properties ofBaCe0.9−xZrxY0.1O3−δ". Journal of Nanomaterials 2008 (2008): 1–5. http://dx.doi.org/10.1155/2008/354258.

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BaCe0.9−xZrxY0.1O3−δpowders were synthesized by a solid-state reaction. Different contents of cerium and zirconium were studied. Pellets were sintered using either conventional sintering in air at1700∘Cor the Spark Plasma Sintering (SPS) technique. The density of the samples sintered by SPS is much higher than by conventional sintering. Higher values of ionic conductivity were obtained for the SPS sample.

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29

Tan, Xinglong, Shaoyu Qiu, Wenyan He, and Daifu Lei. "Functionally Graded Nano Hardmetal Materials Made by Spark Plasma Sintering Technology." Journal of Metastable and Nanocrystalline Materials 23 (January 2005): 179–82. http://dx.doi.org/10.4028/www.scientific.net/jmnm.23.179.

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The properties of nano WC/Co hardmetals prepared by different Spark Plasma Sintering processes were measured. A 4-layer Functionally Graded Materials (FGM) was also obtained by Spark Plasma Sintering technology (SPS), starting from powders of nano WC/10%Co, nano WC/12%Co, micro WC/15%Co and stainless steel disk. The other 3-layer FGM was made from powders of nano 21%Al2O3/ZrO2, nickel and stainless steel. The SPS processing led to FGM free of internal stress, which was measured using Vickers indentations.

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30

Olevsky, Eugene, Evan Khaleghi, Cristina Garcia, and William Bradbury. "Fundamentals of Spark-Plasma Sintering: Applications to Net-Shaping of High Strength Temperature Resistant Components." Materials Science Forum 654-656 (June 2010): 412–15. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.412.

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Spark-plasma sintering (SPS) is an emerging powder consolidating technique which provides significant advantages to the processing of high temperature materials with poor deformability into configurations previously unattainable. Net-shaping capabilities of spark-plasma sintering are analyzed both theoretically and experimentally. Modeling and experimentation are conducted for cylindrical, prismatic, and complex powder specimen shapes. The impact of the “shape factor” on the non-uniformity of temperature, relative density, and grain size spatial distributions is analyzed. The modeling results are compared to the experimentally obtained data on the spark plasma sintering of high strength temperature resistant powder-based materials. The conducted research indicates the promising capabilities and addresses the challenges of spark-plasma sintering of complex-shape parts.

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31

Garcia, Cristina, and Eugene Olevsky. "Numerical Simulation of Spark Plasma Sintering." Advances in Science and Technology 63 (October 2010): 58–61. http://dx.doi.org/10.4028/www.scientific.net/ast.63.58.

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A macro-scale model of spark plasma sintering (SPS) that couples electrical, thermal, stress-strain and densification components is presented. The continuum theory of sintering is incorporated enabling the evolution of the densification based on local conditions, thus a true spatial density distribution could be obtained. Specimen behavior is described through a non-linear viscous constitutive relation. The simulation is based on an FEM computer code. Several examples are shown and results are compared with experimental data available.

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32

Fabrègue, Damien, Bassem Mouawad, Cyril Buttay, Maher Soueidan, Aude Lamontagne, Romain Forte, Michel Perez, et al. "Elaboration of Architectured Materials by Spark Plasma Sintering." Materials Science Forum 706-709 (January 2012): 1885–92. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.1885.

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Spark plasma sintering has been used for decades in order to consolidate a wide variety of materials and permitting to obtain fully dense specimens. This technique has been mainly applied to ceramics. This paper concentrates on an unusual use of spark plasma sintering system: obtaining innovative materials especially architectured ones. Different applications are presented. Firstly, the SPS technique has been used to elaborate nanometers grain size materials or containing nanoscale microstructure. This is possible since the sintering temperature and the holding time are far lower in the SPS compared to other techniques. Then SPS has been used to realize diffusion bonding. In that case again, bonding can be realized at low temperature and for short time. It permits for example to realize bonding between two copper layers which is of a great importance for microelectronic applications. It is worth noting that this bonding can have the same mechanical strength as pure copper even for diffusion time of a few minutes. Secondly, bonding has been also carried out between a metallic layer and a ceramic one. This could lead to design of new layered materials combining interesting properties in terms of mechanical strength but also in terms of electrical resistance. The SPS machine has also been used to obtain porous materials (cobalt alloys or copper) with an adapted microstructure (porosity, tortuosity,). These structures could open new perspectives for biomedical or for microelectronic applications. All these examples lead to a better understanding of the physical processes which happen during spark plasma sintering.

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Chaurasia, Jitender, Muthuchamy Ayyapan, Paridh Patel, and Annamalai Raja. "Activated sintering of Tungsten heavy alloy." Science of Sintering 49, no. 4 (2017): 445–53. http://dx.doi.org/10.2298/sos1704445c.

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In the present work, characterization of sintering behavior of Tungsten heavy alloy has been done through powder metallurgy route using Spark plasma sintering (SPS). Fine powder of Tungsten (<30 ?m) was separately mixed with Ni, Co, Fe, Mo and Cu each with 1 weight%. Spark Plasma Sintering (SPS) technique (1200?C, 20 MPa pressure with 1 min holding time) was used to sinter the mixed powders. The maximum density was observed in W-Ni followed by Co, Fe, Cu, Mo and with least in pure tungsten sample. Optical microscopy as well SEM was done to determine the microstructure and grain coarsening. Due to the short heating time very less grain coarsening was observed. Vickers hardness test was conducted which resulted in maximum hardness in case if W-1Fe SPS sample.

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Juhani, Kristjan, Jüri Pirso, Marek Tarraste, Mart Viljus, and Sergei Letunovitš. "The Influence of Processing Parameters on Mechanical Properties of Spark Plasma Sintered Chromium Carbide Based Cermets." Solid State Phenomena 267 (October 2017): 162–66. http://dx.doi.org/10.4028/www.scientific.net/ssp.267.162.

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Present paper discusses the influence of spark plasma sintering (SPS) on the microstructure and perfomances of chromium carbide based cermets. The effect of SPS parameters (temperature, pressure) is discussed. It is shown that SPS enables to produce more fine grained chromium carbide based cermets compared to conventional liquid phase sintering. Hardness and fracture toughness are exhibited.

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35

Balazsi, Katalin, Mónika Furkó, Piotr Klimczyk, and Csaba Balázsi. "Influence of Graphene and Graphene Oxide on Properties of Spark Plasma Sintered Si3N4 Ceramic Matrix." Ceramics 3, no. 1 (February 5, 2020): 40–50. http://dx.doi.org/10.3390/ceramics3010005.

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The sintering of ceramic matrix composites is usually carried out by raising the sintering temperature below the melting point of components. Spark plasma sintering (SPS) has the capability to densify ceramics at a relatively low temperature in a very short time. Two different additions, multilayered graphene (MLG) and graphene oxide (GrO), were added to Si3N4 ceramic matrix in various amount; 5 wt% and 30 wt%. The influence of reinforcing phase on final properties of spark plasma sintered Si3N4 composite was studied. The uniaxial-pressure-assisted SPS sintering resulted in a preferential alignment of both type of graphene in the Si3N4 ceramic matrix, leading to highly anisotropic properties with lower mechanical behavior but better tribological and electrical properties.

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36

Zhao, Shu Jin, Guo Jing Li, Yang Zhang, Ao Mei, Jin Le Lan, and Yuan Hua Lin. "Synthesis and Thermoelectric Properties of Ca₂Co₂O₅ Ceramics." Key Engineering Materials 434-435 (March 2010): 400–403. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.400.

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The precursor of Ca2Co2O5 was prepared by coprecipitation method. The bulk Ca2Co2O5 samples were prepared by conventional sintering and Spark Plasma Sintering (SPS), respectively. The relative density of bulk Ca2Co2O5 ceramic, which was prepared by conventional sintering is about 75%; while the samples prepared by SPS has a density of 98%. The thermoelectric properties were enhanced by SPS, compared with samples prepared with conventional sintering. The maximum powerfactor of the conventional sintering and SPS samples are 2.70×10-4W∙m-1∙K-2 and 3.85×10-4 W∙m-1∙K-2, respectively.

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37

Baseri, J., R. Naghizadeh, H. R. Rezaie, and F. Golestanifard. "Spark plasma effect on microstructure and mechanical properties of alumina-nickel-cobalt composite." Cerâmica 64, no. 371 (September 2018): 431–35. http://dx.doi.org/10.1590/0366-69132018643712375.

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Abstract Spark plasma sintering (SPS) is an advanced process of sintering materials at low temperatures and short time by creating spark plasma at very high temperatures in the small points and short times, by which materials with high sintering temperature can sinter at lower temperatures. In this study, alumina-nickel-cobalt composites were sintered by SPS and RHP (rapid hot press) methods to investigate the effects of electric pulse on their microstructure and mechanical properties. To this end, sample powders containing alumina, nickel-cobalt aluminate spinel, and aluminum were sintered at 1380 °C under 30 MPa pressure for 10 min by SPS and RHP and then investigated. The densities of both samples were about 98% of theoretical density. Also, hardness and fracture toughness of both samples were about 11 GPa and 14 MPa.m0.5, respectively. The bending strengths of the SPS and RHP samples were 380 and 336 MPa, respectively.

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38

Wang, Heng, Jing Feng Li, and Wei Shu Liu. "Preparation of Ag_xPb_mSbTe_2+m-Based Thermoelectric Materials by MA-SPS Method and Evaluation of their Thermoelectric Properties." Key Engineering Materials 336-338 (April 2007): 850–53. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.850.

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AgxPbmSbTe2+m thermoelectric materials were fabricated using a combined process of mechanical alloying (MA) and spark plasma sintering (SPS). The compound powder was synthesized by mechanical alloying (MA) from elemental powders using a planetary mill after a short time, and high-density bulk samples were fabricated by spark plasma sintering (SPS) at low temperature within a short time (12 minutes). The P-type materials were obtained with electrical properties comparable to the newly reported data. The properties of P-type AgxPbmSbTe2+m-based materials could be improved by optimizing the composition and the process.

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39

Xu, Chun Lai, and He Ping Zhou. "Microstructure and Dielectric Properties of Ba_0.5Sr_0.5TiO₃ Ceramics by Spark Plasma Sintering." Key Engineering Materials 368-372 (February 2008): 59–61. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.59.

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Ba0.5Sr0.5TiO3 (BSTO) ceramics were synthesized by spark plasma sintering (SPS) technique. The phase compositions, microstructure and dielectric properties of BSTO ceramics were investigated. The results indicated that SPS was an alternative sintering technology to synthesize dense BSTO ferroelectric ceramics at low temperature and in a short period.

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Yushin, Denis Igorevich, Andrey Vladimirovich Smirnov, Nestor Washington Solis Pinargote, Pavel Yurievich Peretyagin, and Ramon Torrecillas San Millan. "Modeling Process of Spark Plasma Sintering of Powder Materials by Finite Element Method." Materials Science Forum 834 (November 2015): 41–50. http://dx.doi.org/10.4028/www.scientific.net/msf.834.41.

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This paper investigates and analyses use of numerical modeling by finite element method (FEM) at studying of consolidation processes of materials from powder by spark plasma sintering (SPS). Tasks of SPS process optimization is discussed in detail. Examples of numeric analysis of SPS of current conducting and non-conducting materials are given. Numeric modeling of sample sintering with hybrid method when SPS process is combined with hot pressing (HP) process is studied. Also paper presents development prospects of principles of SPS process numeric modeling.

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Ctibor, Pavel, Josef Sedláček, Libor Straka, František Lukáč, and Karel Neufuss. "Dielectric Spectroscopy of Calcium Titanate Processed by Spark Plasma Sintering." Materials 16, no. 3 (January 20, 2023): 975. http://dx.doi.org/10.3390/ma16030975.

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Calcium titanate (CaTiO3) powder was compacted by spark plasma sintering (SPS). The resulting products were subjected to the phase stability study and dielectric characterization. The change in temperature of SPS between 1100 °C and 1250 °C had a clear and straightforward effect on density, porosity, relative permittivity, loss tangent, and DC resistivity. Since the SPS itself introduces certain oxygen deficiency into Ti-perovskites, all samples were annealed after SPS. However, this post-processing did not mask the effects of the SPS regime. Optical reflectance measurements were completed to compare and quantify the sample coloration and support the dielectric results with corresponding optical band gap estimations. Subtle changes in the CaTiO3 crystal lattice arrangement, completed between 1150 °C and 1250 °C and documented in the literature for conventionally sintered samples, could not be confirmed for SPS-prepared calcium titanate. The novelty of this research work is in producing very stable dielectric ceramics and an indication of the SPS processing parameters suitable for this. The best sample showed at 1 MHz frequency the combination of relative permittivity 370, loss tangent 0.008, and DC resistivity 3 × 1012 Ωm.

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42

Wachowicz, Joanna. "Spark Plasma Sintering – new technology for obtaining tool materials." Annals of WULS, Forestry and Wood Technology 109 (March 31, 2020): 64–69. http://dx.doi.org/10.5604/01.3001.0014.3262.

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Spark Plasma Sintering – new technology for obtaining tool materials. Cemented carbides are a valued tool material used for tools to process, among others, wood-based materials. They are traditionally obtained using high temperatures and long periods. New electric current activated sintering methods make it possible to obtain sinters with good mechanical properties in a short time and low temperature. This paper presents a comparative analysis of conventional and advanced SPS (Spark Plasma Sintering) technology of obtaining cemented carbides.

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43

Babalola, B. J., M. B. Shongwe, B. A. Obadele, P. A. Olubambi, O. O. Ayodele, A. L. Rominiyi, and S. O. Jeje. "Comparative study of spark plasma sintering features on the densification of Ni-Cr binary alloys." MATEC Web of Conferences 249 (2018): 01004. http://dx.doi.org/10.1051/matecconf/201824901004.

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Spark plasma sintering (SPS) has been widely regarded as an advanced powder consolidation technique hich helps in the development of array of engineering materials. Many have been reported in the literature about sintering parameters such as temperature, pressure, heating rate and holding time. However, little or no reports has been made on some of the intricate features such as process time(s), power SPS (KW), pressing speed (mm/min), and average pressing force (KN) on which intering parameters are directly related to. This study aims to investigate the behaviour of spark plasma sintered Ni-17Cr binary alloys with emphasis on the densification, hardness value and spark plasma sintering features such as process time (s), power SPS (KW), pressing speed (mm/min), and the average pressing force (KN). Nickel and chromium powders were milled individually using High energy ball milling for durations of 5hr, 10 hr prior to mixing and subsequent sintering. The sintered 5 hr and 10 hr milled Ni-17Cr binary alloys attained relative densities of 98.72 % and 99.1 % respectively. The Microstructural morphology was examined using Scanning electron microscopy (SEM). The sintered 10 hr milled Ni-17Cr binary alloy revealed the higher hardness.

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44

Jalabadze, Nikoloz, Lili Nadaraia, and Levan Khundadze. "SPS Method for Manufacturing Carbide Materials." Applied Mechanics and Materials 376 (August 2013): 38–41. http://dx.doi.org/10.4028/www.scientific.net/amm.376.38.

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Due the rapid heating rate combined with high pressure by the Spark Plasma Sintering (SPS) technologies possible manufacture a wide range of novel materials with exceptional properties that cannot be achieved using conventional sintering techniques. Hard metals are, from a technical point of view, one of the most successful composite materials. An overview of the metallurgical reactions during the SPS sintering process of powder mixtures for the manufacture of hard metals is presented. The relatively complex phase reactions in the multi-component system TiC-Mo-W-Ni are discussed. There were elaborated a new technology for the fabrication of nanocrystalline hard metals of a new class assigned for the production of articles with high different characteristics. Elaborated materials are characterized by high melting temperature, hardness, wear-resistance, and satisfactory strength at high temperature and corrosive resistance. Through the use of developed technology and the appropriate structural condition gives possibility to achieve high physical-mechanical characteristics. Obtaining of composite materials via elaborated technology is available from the corresponding complex compounds and directly consisting elements too. In this case High-temperature Self-propagation Synthesis (SHS) and spark plasma sintering/synthesis (SPS) process are united and during a single operation it is possible to get not only the powder materials but at the same time obtain required details.

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Amorim, Lucas de Mello, Nério Vicente Jr., Marcos Antonio Coelho Berton, and Cláudia Eliana Bruno Marino. "Harmonic Structured Ti6Al4V by Spark Plasma Sintering." Materials Science Forum 899 (July 2017): 452–57. http://dx.doi.org/10.4028/www.scientific.net/msf.899.452.

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The Ti6Al4V alloy has been applied in situations where mechanical strength, corrosion resistance and biocompatibility are the concern, as in permanent biomedical implants. These material properties are straightly correlated with the microstructure morphology as grain size and crystallographic phases, which is very dependent of the thermal mechanical history and the chemical composition. The Ti6Al4V harmonic structure was primarily achieved by means of Mechanical Ball Milling (MBM) and Spark Plasma Sintering (SPS) using pre-alloyed powder from the plasma rotating electrode processes (PREP). This work aimed at developing the harmonic microstructure by MBM and SPS using pre-alloyed gas atomized powder (GAP). The chemical composition, the microstructure and the hardness were evaluated for the sintered samples and for the commercial wrought annealed conditions, for comparison. The harmonic structure obtained consists of cores containing alpha lath coarse grains surrounded by a three-dimensional network of fine equiaxial grains, while the wrought material shows equiaxial alpha grains in a matrix of beta phase microstructure. The sintered material revealed higher hardness than the wrought alloy.

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Jiang, Runjian, Elisa Torresani, Guodong Cui, and Eugene A. Olevsky. "Proportional Integral Derivative Control in Spark Plasma Sintering Simulations." Materials 14, no. 7 (April 3, 2021): 1779. http://dx.doi.org/10.3390/ma14071779.

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The prediction of microstructure evolution and densification behavior during the spark plasma sintering (SPS) process largely depends on accurate temperature regulation. A loop feedback control algorithm called proportional integral derivative (PID) control is a practical simulation tool, but its coefficients are often determined by an inefficient “trial and error” method. This paper is devoted to proposing a numerical method based on the principles of variable coefficients to construct an optimal linear PID controller in SPS electro-thermal simulations. Different types of temperature profiles were applied to evaluate the feasibility of the proposed method. Simulation results showed that, for temperature profiles conventionally used in SPS cycles, the PID output keeps pace with the desired profile. Characterized by an imperfect time delay and overshoot/undershoot, the constructed PID controller needs further advancement to provide a more satisfactory temperature regulation for non-continuous temperature profiles. The first step towards a numerical rule for the optimal PID controller design was undertaken in this work. It is expected to provide a valuable reference for the advanced electro-thermal modeling of SPS.

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47

Zhang, Di, Ming Gang Wang, and Zhan Kui Zhao. "Nanocrystalline ZrO₂ Porous Ceramics Fabricated by SPS." Advanced Materials Research 306-307 (August 2011): 1398–401. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.1398.

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The porous ZrO2 ceramics was prepared by spark plasma sintering (SPS) at 520 °C. A dense closed micro-cellular ceramic structure was fabricated with micron Al90Mn9Ce1 alloy powders clading by 10 wt% ZrO2 nano-powder. SEM image showed that the thickness of ceramic cell wall was 1.0 - 2.0 μm. After deep corrosion with 10% HCl, an integrity nanocrystalline ZrO2 porous sample was obtained. Based on the experimental results, the transient spark plasma sintering mechanism of micron-nano mixing powder was also studied.

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48

Naimi, Foad, Jean-Claude Niepce, Mostapha Ariane, Cyril Cayron, José Calapez, Jean-Marie Gentzbittel, and Frédéric Bernard. "Joining of Oxide Dispersion-Strengthened Steel Using Spark Plasma Sintering." Metals 10, no. 8 (August 2, 2020): 1040. http://dx.doi.org/10.3390/met10081040.

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Difficulties with joining oxide dispersion-strengthened (ODS) steels using classical welding processes have led to the development of alternative joining techniques such as spark plasma sintering (SPS). SPS, which is classically employed for performing sintering, may also be used to join relatively large components due to the simultaneous application of electrical pulsed current and uniaxial charge. SPS technology was tested by joining two ODS steel disks. The preliminary tests showed that it is necessary to control surface roughness before joining. Furthermore, the use of ground and lapped surfaces seemed to improve the quality of the interface. Tensile tests on two ODS cylinders joined using SPS were performed at 750 °C without any additives. Failure occurred away from the interface with a total elongation close to 50% and an ultimate stress of 110 MPa.

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Yamamoto, Go, Yoshinori Sato, Toru Takahashi, Mamoru Omori, Toshiyuki Hashida, Akira Okubo, Sadao Watanabe, and Kazuyuki Tohji. "Preparation of Single-Walled Carbon Nanotube Solids and Their Mechanical Properties." Journal of Materials Research 20, no. 10 (October 2005): 2609–12. http://dx.doi.org/10.1557/jmr.2005.0345.

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Single-walled carbon nanotubes (SWCNTs) were successfully solidified without any additives by hot-pressing and spark plasma sintering (SPS). The elastic modulus and fracture strength of the SWCNT solid prepared by the SPS method were about three and two times higher than that of the hot-pressed SWCNT solid prepared under the same processing condition. The enhancement of the mechanical properties of the SPS specimen may be due to the formation of comparatively stronger bond between SWCNTs, which is possibly brought about by the spark plasma generated in the SPS process.

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50

Takeuchi, Tomonari, Claudio Capiglia, Nalini Balakrishnan, Yasuo Takeda, and Hiroyuki Kageyama. "Preparation of Fine-grained BaTiO3 Ceramics by Spark Plasma Sintering." Journal of Materials Research 17, no. 3 (March 2002): 575–81. http://dx.doi.org/10.1557/jmr.2002.0081.

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Dense BaTiO3 ceramics consisting of fine grains were prepared using fine powder (average grain size of 0.06 μm; BT006) as a starting material and the spark plasma sintering (SPS) method. The powder was densified to >95% of theoretical x-ray density by the SPS process, and the average grain size of the resulting ceramics was <0.5 μm; the particle size of the initial powder significantly affects the grain size of the resulting SPS pellets. Fixed-frequency (100 kHz), room-temperature permittivity measurements of the BT006-SPS ceramics showed relatively low values (3000–3500) compared with those (typically 5000) for SPS ceramics consisting of larger grains (approximately 1 μm). Lower permittivity was attributed to poor development of ferroelectric domains in the ceramics, which originated from incomplete development of the tetragonal structure as well as the presence of a local orthorhombic structure.

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