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以天然红柱石为原料,采用高温煅烧使其发生莫来石化转变,然后经喷雾造粒、热处理,得到热喷涂用球形莫来石/SiO2复合粉末。采用大气等离子喷涂工艺在1Cr18Ni9Ti不锈钢上喷涂莫来石/SiO2粉末制得涂层,对涂层的微观组织、硬度和相成分进行了分析。研究结果表明:天然红柱石粉末莫来石化后,其相组成主要为莫来石和游离态SiO2;喷雾造粒粉末在1 000℃热处理后,松装密度得到改善;涂层具有良好的微观形貌,表面显微硬度较高,主要由莫来石、石英和非晶玻璃相构成。
Using natural andalusite as raw material, the mullite transformation takes place by high-temperature calcination, and then granulated and heat-treated by spraying to obtain the spherical mullite / SiO2 composite powder for thermal spraying. The coatings were prepared by spraying the mullite / SiO2 powder on the 1Cr18Ni9Ti stainless steel by atmospheric plasma spraying. The microstructure, hardness and phase composition of the coating were analyzed. The results show that the mullitization of natural andalusite is mainly composed of mullite and free SiO2. After the spray granulation powder is heat treated at 1000 ℃, the bulk density is improved. The coating has good microstructure, Surface microhardness higher, mainly composed of mullite, quartz and amorphous glass phase.