Low Temperature Solid Phase Sintering of Nanoscaled Tungsten Powder

After compacted with a rubber die,the traditional tungsten powders and nanoscaled tungsten powders were sintered in order to investigate the shrinkage kinetic curves in hydrogen and study the relationship between the sintered density and sintering temperature in a high-temperature dilatometer.After sintered ,the microstructure of the compacts were examined by SEM.The compact of nanoscaled tungsten powders started to shink at 250℃.The shrinkage rate became fast from 450℃ to 1450℃ and the temperature corresponding to the highest shrinkage rate of nanoscaled tungsten powders was 1200℃.The relative density of sintered sample in 1500℃×20min was 96.4%,but when sintered in vacuum,the relative density was 96.7% and the grain size was about 5.8μm.The compact of traditional tungsten powders started to shrink at 1400℃.After sintered at 1500℃,the sample had a relative density of 66.2%;When sintered in vacuum at 2250℃,the relative density was 96.9%,the averge grain size was 223μm.