大型铁酸镍基金属陶瓷惰性电极电解腐蚀研究

采用热压法制备了D150mm×20mm的铁酸镍基金属陶瓷惰性阳极,进行100A规模电解试验·在900℃下,通以100A电流,进行了24h的电解实验,在整个过程中槽电压比较稳定,表现出良好的导电性能·对电解后阳极试样进行电子显微分析,发现电解质对阳极的腐蚀主要有两个过程:首先是AlxOyF(2y+z-3x)-z离子在阳极放电,生成的氧与阳极中的金属发生氧化反应,产生的金属氧化物溶解在电解质熔盐中;其次阳极反应生成的AlF3沉积在阳极中的空隙中·研究认为阳极腐蚀层的热膨胀系数与阳极基体不同,而引起在阳极冷却过程中表面起层、剥离的现象·初步折算的阳极腐蚀速率为18mm/a·

Electrolysis Corrosion of Large-Size Ferrous-Nickel-Based Cermet Inert Electrode

A ferrous-nickel-based cermet inert anode was prepared by means of hot-pressing with a size up to D150 mm × 20 mm to apply to a 100 A electrolysis testing for 24 h at 900°C. In the whole electrolysis process the cell voltage was steady, which manifests that the anode is good at electrolytic conduction. According to the SEM results of the anode after electrolysis, it was found that the anodic corrosion due to electrolyte includes two processes. One is the reoxidation reaction between the oxygen ions produced from the anodic discharging of AlxOyFz^(2y+z-3x)- ions and the metal in anodic substrate, which causes the metallic oxides to be dissolved in electrolytic molten salt. The other is the anodic deposition of AlF3 into gaps, which is produced from the anodic reaction. A conclusion is thus drown that the coefficient of the anodic corrosion layer is different from that of anodic substrate and such a difference will result in the delamination even peeling off of the surface of anode in the cooling process. The corrosion rate is evaluated as 18 mm/a.