烧结工艺对纳米AgSnO2复合材料致密度的影响

对化学镀法制备的纳米AgSnO2粉末分别采用常压、热压和真空烧结的方法制成AgSnO2复合材料，研究了烧结方法及工艺对致密度的影响。结果表明，采用常压烧结，虽然成型压力、烧结温度和时间对致密度有一定的影响，但复压、复烧后，材料的致密度十分接近。热压能在短时间内获得96％以上的致密度，但复烧时膨胀严重，甚至出现鼓泡。真空烧结对去除吸附物有利，但仍会有少量残留并导致复烧时出现膨胀。在较低的压力下成型并采用分段保温烧结，不但能消除吸附物的影响，复烧后还可以得到94％的致密度。研究表明，纳米粉末表面大量的吸附物以及由此造成的封闭在压坯中的气体是阻碍烧结致密化的根本原因。

Influence of Sintering Processes on the Density of Nano-AgSnO2 Composites

The influence of sintering process on the density of nano-AgSnO2 composite was investigated using AgSnO2 powder prepared by electroless plating, adopting air sintering, hot pressing and vacuum sintering. The results show that density changed with compacting pressure, sintering temperature and sintering time when sintered in air, while the final density was close after repressing and resintering. For hot pressing, a density with higher than 96% could be achieved in a short time, but serious expansion and blistering ocurred. Vacuum sintering could help to wipe off adsorbates, but some residual still remained in the compact, and the expansion occurred during resintering. Low pressure compaction and step isothermal sintering could remove most of the adsorbates, and a high density of 94% was obtained after resintering. The large amount of absorbates on nano-AgSnO2 powder surface which led gases closed in the compact during sintering were found to be the main causes that affected densification process .