初始粉体状态对氧化铝/氧化锆纳米陶瓷烧结性能的影响

Effects of starting powders on sinterability of Al_(2)O_(3)-ZrO_(2) nanoceramics

通过放电等离子体烧结(SPS),分别以纳米多晶粉体和非晶粉体作为原料制备了Al2O3-ZrO2纳米陶瓷复合材料,并研究了初始粉体状态对致密化过程和微观结构的影响。将纳米多晶粉体通过SPS烧结为致密的纳米块体,所需的最低烧结温度为1 400℃,所得产品的晶粒尺寸约为320nm;非晶粉体完全致密所需的SPS温度为1 200℃,所得产品的晶粒尺寸约为150nm。相比于纳米多晶粉体,非晶粉体可以在较低的温度下烧结成为致密纳米块体,我们将这一现象归结为非晶粉体在烧结中的相转变。这一发现为纳米陶瓷块体的低温烧结提供了新的思路。

In this work,Al2O3-ZrO2 nanocomposites were prepared by spark plasma sintering(SPS)of nanocrystalline and amorphous powders,respectoively,and effects of starting powders on the densification and microstructure of the nanocomposites were investigated.To obtain dense nanocomposites,the minimum SPS temperature for nanocrystal powders was 1 400℃,and the resulting grain sizes were about320 nm.For amorphous powders,however,the hot pressing temperature was as low as 1 200℃,and the products exhibited finer grains of about 150 nm.It was confirmed that amorphous powders could be hot pressed into dense nanocomposites at lower temperatures than nanocrystalline powders,and the easier densification of amorphous powders was attributed to the phase transformation of amorphous particles in sintering.This finding could provide new guidance for low temperature sintering of bulk nanocomposites.