Si_3N_4结合SiC材料在铝电解槽中的损毁机理研究

Study on the corrosion mechanisim of Si_3N_4 bonded SiC materials in aluminum reduction cell

采用自制的抗冰晶石侵蚀试验炉,模拟了Si3N4结合SiC制品在电解铝槽中的工作情况,并借助SEM、X射线衍射仪及能谱仪(EPAX)研究了Si3N4结合SiC制品不同位置的损毁机理。结果表明:Si3N4结合SiC制品在空气部分的损坏主要是由于Si3N4和SiC氧化导致的;而在冰晶石电解质与空气界面处,由于化学反应形成的氧化—侵蚀—渗透恶性循环使得侵蚀最为严重,电解质在金属铝液中的溶解和由于试样本身结构中的气孔可能是Si3N4结合SiC制品在金属铝液中发生侵蚀的主要原因。

Service of Si3N4 bond SiC refractories in aluminum reduction cell was simulated by self- designed furnace for cryolite- resistance testing in this paper. Different positions of refractories＇ corrosion meehanisim were studied by XRD, SEM and EPAX. It was indicated by the results that： part of service of Si3N4 bond SiC refractories in air was destroyed mainly because of the oxidation of Si3N4 bond SiC; while part at the interface of air and cryolite was badly destroyed as a result of circle of oxidation - corrosion- oxidation; the corrosion of part in the melt aluminum may because of the solution of electrolyte in metal melt and pores in its structure.