Si_3N_4结合SiC材料在稀土电解槽中的应用及效果

Evaluation of Si_3N_4 Bonded SiC Used in the Rare Earth Electrolysis Cell

采用Si3N4结合SiC板作为3kA液态下阴极稀土金属电解槽的侧壁材料,进行了实际电解工艺试验,考察了Si3N4结合SiC材料在稀土熔盐电解槽上的使用效果,研究表明,Si3N4结合SiC材料在稀土熔盐中腐蚀较严重,尤其是靠近电解槽阴极位置,由于弥散在电解质中的金属雾和阳极产生的气体加剧了Si3N4结合SiC材料受腐蚀破坏;板材由于受热不均产生了开裂现象,且开裂位置会加剧材料的腐蚀破坏,进一步的分析表明,Si3N4结合SiC材料在稀土熔盐中主要受腐蚀的是含Si3N4的结合相。

A kind of Si3N4 bonded SiC plate was used as the sidewall of a 3000A submerged-liquid cathode rare earth electrolysis cell,and electrolysis was done to investigate its effect.The photographs and micro images show that Si3N4 bonded SiC material is corroded by molten salt of rare earth,and the plate located closest to the cathode suffers severe corrosion caused by molten metal mist layer generated from liquid cathode.And severe cracking can be viewed from the images,which may due to non-uniform temperature on Si3N4 bonded SiC plate.This severe cracking will increase the corrosion.Micro analysis shows that Si3N4 combination phase is eroded by molten rare earth salt and molten metal more easily than other phase of Si3N4 bonded SiC.