Thermal-electrical Coupled Analysis Of Temperature Distribute Regularity For Spark Plasma Sintering

The research in the generation and distribution of temperature in SPS and buildingthe basic laws are of great significance for the preparation of materials and products inSPS. The electrically non-conductive material of SiC ceramics and the conductingmaterial of CuNi alloy are prepared by the technology of SPS in the paper, The sparkplasma sintering of the two materials are simulated by Marc software on the basis of theexperiment results, and got different temperature curves, then compared with theexperiment results, the distribution rules of the temperature and current of the twomaterials in SPS .are obtained. The temperature distribution of the two materials in thesame sintering condition is compared, then the differences and similarities of temperaturefield distribution of the electrically non-conductive material and the conducting materialare got in the SPS processing.The material of SiC ceramic is prepared in 1800℃, 1900℃and 2000℃in SPS, theexperimental temperature-time curves of different temperature are got with the currentloading, the spark plasma sintering of the material of SiC ceramic is simulated by Marcsoftware on the basis of the experiment results and that the concept of equivalent radiationcoefficient was presented and determined. The distribution rules of temperature andcurrent in initial heat preservation stage, in final heat preservation stage and in finalcooling end stage have been studied in SPS processing. In the initial stage of the heatpreservation, the temperature of the central part of the sample has basically achievedsintering temperature, but at the moment, the temperature of the sample is not uniform,temperature between the parts of die is also quite different and temperature of the samplein the central is higher than in the edge. In the end of heat preservation, the temperature inthe central of the sample is higher than the actual sintering temperature, the temperaturedifferent between the parts and die decreases gradually also. In final cooling end stage, thetemperature distribution in whole dies is quite uniform, the temperature of sample is thehighest, the current density of the contact surface of punch and die is the biggest, but thevalue of the current density is much smaller than that in the end of heat preservation.The material of CuNi alloy is prepared in 650℃, 700℃and 850℃in SPS, the distribution rules of temperature and current in initial heat preservation stage, in final heatpreservation stage and in final cooling end stage have been studied in SPS processing,which is the same to the electrically non-conductive material of SiC ceramics in the threestages, the differentia between the two materials is that the current density of theconducting material of CuNi alloy is not zero.The spark plasma sintering of the materials of SiC ceramic and CuNi alloy aresimulated under the same sintering condition for 650℃, 700℃and 850℃, and thesimulation results were compared and analyzed, the differences of temperature fieldbetween the two materials are the heating rate of conducting material is higher thanelectrically non-conductive material, and the temperature distribution in the initial stage ofthe heat preservation is more uniform than electrically non-conductive material.