光伏废料制备Si3N4-SiC材料的抗氧化性和抗侵蚀性

将光伏废料经酸洗除杂后,与硅粉按85∶15的质量比配料,以聚乙二醇做结合剂,成型为10 mm×10 mm×20 mm的生坯后,在1380℃保温2 h氮化制成Si3N4-SiC材料,然后研究了该Si3N4-SiC材料的抗氧化性和抗侵蚀性。结果表明:1)制备的Si3N4-SiC材料在空气气氛中抗氧化性较好,主要是由于其氧化产物Si2N2O和SiO2填充气孔,促进烧结,提高了试样的致密度。2)在静态熔盐(Na3AlF6)中的抗侵蚀性能较好,主要是由于Na3AlF6渗入气孔中,使其显气孔率降低。3)在动态熔盐中的抗侵蚀性相对变差,主要是由于CO2气体的搅拌和对Si3N4、SiC的氧化二者共同作用的结果。

Oxidation resistance and corrosion resistance of Si3N4-SiC materials prepared by photovoltaic waste

The Si3N4-SiC material was prepared using acid pickled photovoltaic wastes and silicon powder as starting materials in a mass ratio of 85∶15,polyethylene glycol as the binder,shaping to 10 mm×10 mm×10 mm green bodies,and nitridizing at 1380℃ for 2 h.Then the oxidation resistance and the corrosion resistance of the obtained Si3N4-SiC material were studied.The results show that(1)the Si3N4-SiC material has strong oxidation resistance in air atmosphere,mainly due to the filled pores by its oxidation products Si2N2O and SiO2,which promote sintering and improves the density;(2)the Si3N4-SiC material has good corrosion resistance in static molten salt(Na3AlF6),mainly due to the infiltration of Na3AlF6 into the pores,which reduces the apparent porosity greatly;(3)the corrosion resistance of the Si3N4-SiC material in dynamic molten salt is relatively poor,mainly due to the combination of CO2 gas agitation and the oxidation of Si3N4 and SiC.