烧结碳化硅是一种有前途的高温结构材料,可用作陶瓷发动机、化学反应器和热交换器的主要零部件。许多研究表明,SiC对熔盐腐蚀十分敏感。Smialek 和 Jecobson 的工作指出,高温钠盐腐蚀5～lO分钟,SiC的弯曲强度下降25％。本文研究了α—SiC在1000℃用碳酸钠分别腐蚀5′、10′、60′及48小时后的显微结构及腐蚀产物。试验用材料含有约3％体积浓度的自由碳,石墨夹杂大部分集结在三角晶界处。实验结果表明,在高温下Na_2CO_3对SiC有严重的腐蚀作用,在SiC表面形成大量针孔。图1是用HF酸除去表面腐蚀产物后的表面及横截面照片,腐蚀坑呈锥形,表面SiC晶粒上有腐蚀斑点及沟糟,腐 Sintered silicon carbide is a promising high temperature structural material that can be used as a major component of ceramic engines, chemical reactors and heat exchangers. Many studies show that SiC is very sensitive to molten salt corrosion. Smialek and Jecobson’s work pointed out that high temperature sodium salt corrosion 5 ~ lO minutes, SiC bending strength decreased by 25%. In this paper, the microstructure and corrosion products of α-SiC after 5, 10, 60, and 48 hours were respectively etched with sodium carbonate at 1000 ℃. The test material contains about 3% by volume of free carbon, the majority of graphite inclusions at the triangular grain boundaries. The experimental results show that Na_2CO_3 has a serious corrosion effect on SiC at high temperature, and a large number of pinholes are formed on the surface of SiC. Figure 1 is HF acid removal of surface corrosion products after the surface and cross-section photos, the corrosion pit was tapered, the surface of the SiC grains have corrosion spots and ditch bad, rot