scholarly journals Fabrication of graded alumina by spark plasma sintering

2021 ◽  
Author(s):  
Eszter Bódis ◽  
Zoltán Károly
Keyword(s):  
Spark Plasma Sintering ◽  
Materials Science ◽  
Single Step ◽  
Functionally Graded ◽  
Large Temperature ◽  
Graded Materials ◽  
Plasma Sintering ◽  
Gradient Microstructure ◽  
Spark Plasma ◽  
Length Width

AbstractFunctionally graded materials (FGMs) attract considerable interest in materials science and industry, since their composition or morphology gradually changes along their length, width, or height, which provides new approach for the development of multifunctional materials. In this paper, we studied the fabrication of a gradient microstructure in alumina (Al2O3) by spark plasma sintering (SPS). During the SPS process, the applied asymmetric graphite tool configuration causes a large temperature gradient, which results in a gradually changing morphology in Al2O3 ceramics. The local temperatures were quantitatively measured through extra thermocouples during SPS processes with various asymmetric configurations. In the most asymmetric configuration, a maximum vertical temperature difference of 225 °C was detected within the sample treated at a sintering temperature of 1300 °C and a pressure of 25 MPa applied 200 °C·min−1 heating rate. The microstructure investigations demonstrated the morphology gradient in the ceramic: one part of the Al2O3 exhibited fine, nanostructured morphology with large open and permeable pores, whereas the other part was solid without pores. Our investigations show that a gradient Al2O3 ceramic can be produced with a single-step SPS process, which offers new directions in FGMs research. With an asymmetric sintering configuration and the sintering conditions, the structure of the ceramic, such as porosity, can be designed according to the requirements of the application area.

scholarly journals Porosity and Microstructure Iron-Based Graded Materials Sintered by Spark Plasma Sintering and the Conventional Method

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 264
Author(s):  
Krzysztof Zarębski ◽  
Piotr Putyra ◽  
Dariusz Mierzwiński
Keyword(s):  
Spark Plasma Sintering ◽  
Graded Materials ◽  
Gradient Zone ◽  
Die Filling ◽  
Plasma Sintering ◽  
Gradient Microstructure ◽  
Conventional Sintering ◽  
Spark Plasma ◽  
Local Range ◽  
Sintering Method

Using PNC-60 powder with the addition of graphite, cylindrical products characterized by different compositions of core and outer layers were made. Some compacts were sintered via the conventional process, while others were subjected to the spark plasma sintering method (SPS) at different times and temperatures. The gradient microstructure was obtained in the transition zone by mixing powders during die filling, followed by pressing and diffusion during sintering. The effect of sintering parameters on the nature of the gradient zone and the morphology of the pores was shown. After conventional sintering, the gradient zone was wider than it was after SPS. Via SPS, the short sintering time confined the diffusion to a local range, making its influence on the gradient structure negligible. Differences in the microstructure were confirmed by functional description.

Preparation of Mg-W Graded Materials by Spark Plasma Sintering

2008 ◽  
Vol 368-372 ◽  
pp. 1869-1871
Author(s):  
Qiang Shen ◽  
Ying Hu Liu ◽  
Jing Zhou ◽  
Guo Qiang Luo ◽  
Lian Meng Zhang
Keyword(s):  
Spark Plasma Sintering ◽  
Low Temperatures ◽  
Functionally Graded ◽  
Front Face ◽  
Density Range ◽  
Graded Materials ◽  
Compression Waves ◽  
Plasma Sintering ◽  
Mass Fractions ◽  
Spark Plasma

A new kind of functionally graded materials (FGM) with density gradient has come to show great potentials as flier-plates for creating quasi-isotropic compression waves. In order to meet the demand of lower density in the front face and wider density range for such flier-plate, Mg with a density of 1.74g/cm3 and W of 19.3g/cm3 are selected to make Mg-W system density graded materials. Mg-W alloys with various mass fractions of Mg and W were sintered by spark plasma sintering (SPS) technique at low temperatures, and the processing of densification is mainly investigated. It is found that, up to 92wt%W, the Mg-W alloys can be fully densified at 873K due to the conglutination of Mg particles. The Mg-W alloys still exist as a mechanical mixture of Mg and W. Finally, the Mg-W density graded materials with a density change from 1.74g/cm3 to 10.55g/cm3 have been successfully prepared.

Preparation of Functionally Graded Cu/AlN/Cu Electrode Materials for Thermoelectric Devices

2007 ◽  
Vol 336-338 ◽  
pp. 2613-2615 ◽  
Author(s):  
Huai Quan Zhang ◽  
Jing Feng Li
Keyword(s):  
Spark Plasma Sintering ◽  
Functionally Graded Materials ◽  
Electrode Materials ◽  
Functionally Graded ◽  
Thermoelectric Devices ◽  
Graded Materials ◽  
Step Process ◽  
Plasma Sintering ◽  
Spark Plasma

The Cu/AlN/Cu functionally graded materials (FGMs) were successfully fabricated using the spark plasma sintering (SPS) method, and a two-step process was used. First, a symmetrical porositygraded AlN plate was prepared using AlN powder consisting of particles of varying sizes. Afterwards, graded Cu/AlN/Cu samples were made by introducing Cu into the pores of the external, porous AlN layer.

Functionally Graded Nano Hardmetal Materials Made by Spark Plasma Sintering Technology

2005 ◽  
Vol 23 ◽  
pp. 179-182 ◽  
Author(s):  
Xinglong Tan ◽  
Shaoyu Qiu ◽  
Wenyan He ◽  
Daifu Lei
Keyword(s):  
Stainless Steel ◽  
Internal Stress ◽  
Spark Plasma Sintering ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
The Other ◽  
Graded Materials ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintering Processes

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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