scholarly journals Polarity Induced Grain Growth of Gadolinium doped Ceria under Field‐Assisted Sintering Technology / Spark Plasma Sintering (FAST/SPS) conditions

2020 ◽  
Author(s):  
Sree Koundinya Sistla ◽  
Tarini Prasad Mishra ◽  
Yuanbin Deng ◽  
Anke Kaletsch ◽  
Martin Bram ◽  
...  
Keyword(s):  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Doped Ceria ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Field Assisted Sintering ◽  
Gadolinium Doped Ceria

scholarly journals Field-Assisted Sintering/Spark Plasma Sintering of Gadolinium-Doped Ceria with Controlled Re-Oxidation for Crack Prevention

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3184 ◽  
Author(s):  
Tarini Prasad Mishra ◽  
Alexander M. Laptev ◽  
Mirko Ziegner ◽  
Sree Koundinya Sistla ◽  
Anke Kaletsch ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Dwell Time ◽  
Elevated Temperatures ◽  
Sintering Temperature ◽  
Doped Ceria ◽  
Reducing Atmosphere ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Field Assisted Sintering ◽  
Gadolinium Doped Ceria

Gadolinium-Doped Ceria (GDC) is a prospective material for application in electrochemical devices. Free sintering in air of GDC powder usually requires temperatures in the range of 1400 to 1600 °C and dwell time of several hours. Recently, it was demonstrated that sintering temperature can be significantly decreased, when sintering was performed in reducing atmosphere. Following re-oxidation at elevated temperatures was found to be a helpful measure to avoid sample failure. Sintering temperature and dwell time can be also decreased by use of Spark Plasma Sintering, also known as Field-Assisted Sintering Technique (FAST/SPS). In the present work, we combined for the first time the advantages of FAST/SPS technology and re-oxidation for sintering of GDC parts. However, GDC samples sintered by FAST/SPS were highly sensitive to fragmentation. Therefore, we investigated the factors responsible for this effect. Based on understanding of these factors, a special tool was designed enabling pressureless FAST/SPS sintering in controlled atmosphere. For proof of concept, a commercial GDC powder was sintered in this tool in reducing atmosphere (Ar-2.9%H2), followed by re-oxidation. The fragmentation of GDC samples was avoided and the number of micro-cracks was reduced to a minimum. Prospects of GDC sintering by FAST/SPS were discussed.

Grain growth kinetics in CoCrFeNi and CoCrFeMnNi high entropy alloys processed by spark plasma sintering

2019 ◽  
Vol 791 ◽  
pp. 1114-1121 ◽  
Author(s):  
M. Vaidya ◽  
Ameey Anupam ◽  
J. Vijay Bharadwaj ◽  
Chandan Srivastava ◽  
B.S. Murty
Keyword(s):  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Growth Kinetics ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Grain Growth Kinetics

NdFeB Type Magnets Produced by Spark Plasma Sintering

2014 ◽  
Vol 802 ◽  
pp. 585-589 ◽  
Author(s):  
M. Alberteris Campos ◽  
N. Vicente ◽  
I.F. Machado ◽  
K.S.T. de Souza ◽  
D. Rodrigues ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Alloying Element ◽  
Consolidation Process ◽  
Ndfeb Magnets ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Typical Temperature

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.

scholarly journals The Effect of Sintering Temperature on Microstructure and Properties of 94wt% WC - 3wt% TiC - 6wt% Co Sintered by Spark Plasma Sintering

2021 ◽  
Author(s):  
Vahid Aghaali ◽  
Touradj Ebadzadeh ◽  
Seyed Mohammad Zahraee ◽  
Seyed Mohammad Mirkazemi
Keyword(s):  
Fracture Surface ◽  
Tungsten Carbide ◽  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Apparent Density ◽  
Sintering Temperature ◽  
Total Density ◽  
Microstructure And Properties ◽  
Plasma Sintering ◽  
Spark Plasma

Abstract Cemented carbide 94wt% WC − 3wt% TiC − 6wt% Co was sintered by spark plasma sintering at various temperatures of 1200, 1300, and 1400°C and the effect of sintering temperature on the microstructure and properties of this type of hard metals, such as total density, apparent density, hardness, and fracture surface were measured and observed using Field Emission-Scanning Electron Microscopy(FE-SEM), Optical Microscopy (OM), X-ray diffractometry (XRD) and mechanical test instruments. The results showed that the apparent density of the samples increased with increasing sintering temperature from 1200℃ to1300℃ from 13.98 g/cm3 to 14.23 g/cm3, respectively. But in the case of sample sintered at 1400℃, the density was reduced to 14.20 g/cm3. Also, micro-hardness results showed that the hardness of sintered samples increased with the increase of sintering temperature. For the sample sintered at 1200°C the hardness value of 1746.41HV was obtained which increased with increasing sintering temperature from 1300℃ to 1400℃ from 2094.33HV to 2280.97HV, respectively. At the optimum sintering temperature, it was found that TiC inhibited the grain growth of tungsten carbide and increased the hardness values. In addition, as expected, the grain growth of tungsten carbide increased with increasing sintering temperatures. Examination of the fracture surface of sintered samples at different temperatures also showed that brittle fracture involves fracture.

SPS Temperature Influence on the Composition, Structure and Magnetic Properties of Hematite Ceramics

2021 ◽  
Vol 1045 ◽  
pp. 102-108
Author(s):  
Alexey Ognev ◽  
Alexander S. Samardak ◽  
Vladimir Pechnikov ◽  
Evgeniy Papynov
Keyword(s):  
Magnetic Properties ◽  
Spark Plasma Sintering ◽  
Ceramic Materials ◽  
Weak Ferromagnetism ◽  
Initial Study ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Composition Structure ◽  
Field Assisted Sintering ◽  
Powder Metallurgy Methods

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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