二次挂浆工艺对铸造用SiC基泡沫陶瓷性能的影响

采用有机前驱体浸渍法制备SiC基泡沫陶瓷过滤器。研究了一次挂浆后的坯体分别经烘干和预烧后进行二次挂浆,制备的泡沫陶瓷在质量增加和抗热震性方面的差异,以及预烧温度对质量增加和抗热震性的影响。结果表明:1)二次挂浆制备工艺制备的SiC基泡沫陶瓷的室温抗压强度明显高于一次挂浆工艺制备的,但抗热震性又明显低于一次挂浆的。2)对二次挂浆制备的泡沫陶瓷,无论是相同的浆料二次挂浆还是不同浆料同样挂浆量挂浆,烘干后直接进行二次挂浆制得的SiC基试样的热震次数要远高于经预烧后进行二次挂浆制得试样的。3)对预烧后二次挂浆制备的泡沫陶瓷,预烧温度越高,其抗热震性越差。

Impact of two-step slurry coating process on properties of SiC-based foam ceramics for casting

The SiC-based foam ceramic filters were fabricated by organic precursor impregnation.The effects of the slurry recoating using different green bodies(heat treated by drying or pre-burning after one slurry coating)as well as the pre-burning temperature on the mass increase and the thermal shock resistance of the foam ceramics were studied.The results demonstrate that compared with the SiC-based foam ceramics prepared by the one-step slurry coating process,those by the two-step slurry coating process present obviously higher cold compressive strength,but obviously worse thermal shock resistance;with the same amount of slurry coating,no matter with the same slurry or not,the specimens prepared from recoating the dried green bodies perform much better thermal shock resistance than those from the pre-burned green bodies;meanwhile,for the specimens prepared from slurry recoating the pre-burned green bodies,the higher the pre-burning temperature,the worse the thermal shock resistance.