Sintering process of nanoscale tungsten powder

Nanosized tungsten powder with a mean particle size of 60 nm, which was prepared by catalysis-gel process, was used as raw material. After compacted with a steel die, the green compact was sintered in hydrogen in order to investigate its shrinkage kinetic curve. The changes of grain size and relative density during sintering at different temperatures for different sintering time were tested. It is shown that the compact of nanosized tungsten powder starts to shrink at 200℃ and stops shrinking at 1 300℃. The highest shrinkage rate occurs at 1225℃. From 1 000℃ to 1200℃, the relative density increases by 24%. After sintered at 1200℃ for 120 min, the average grain size is 5μm, and the relative density is 95%.