Sintering process of nanoscale tungsten powder
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摘要: 采用催化-凝膠法制備的平均粒徑60nm的納米鎢粉為原料,經鋼模壓制成生坯,用高溫膨脹儀測定了納米鎢粉坯體的燒結收縮動力學曲線;然后分別測定了不同燒結溫度和燒結時間下燒結體晶粒尺寸和相對密度的變化.結果表明,納米鎢粉的坯體在200℃開始收縮,1300℃基本停止收縮.從1000℃到1200℃,其相對密度提高了24%,是致密化過程最快的階段.在1200℃×120min的燒結工藝下得到燒結體相對密度為95%,晶粒尺寸為5μm的鎢材.Abstract: 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%.
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Key words:
- nanoscale tungsten powder /
- sintering process /
- shrinkage kinetic /
- relative density /
- grain size
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