NiFe2O4基金属陶瓷材料的制备及其耐腐蚀性能

采用传统粉末冶金技术制备了铝电解用Cu-NiFe2O4和Ni-NiFe2O4金属陶瓷惰性阳极,并对其在Na3AlF6-Al2O3熔体中的腐蚀行为进行了研究.研究结果表明:NiFe2O4基金属陶瓷阳极的腐蚀行为与热力学计算结果吻合;金属Cu与NiFe2O4陶瓷的润湿性能不好,Cu-NiFe2O4金属陶瓷的致密化和导电性能难以提高;致密度过低时,会导致金属相高温氧化和电解质浸渗,电极肿胀、开裂;在电解过程中,5%Cu-NiFe2O4存在金属相聚集和在陶瓷基体中Fe优先溶解的现象,但金属铜并未发生阳极溶解;5%Ni-NiFe2O4金属陶瓷易实现致密化烧结,在电解过程中表现出良好的耐腐蚀性能,会发生金属Ni的阳极溶解,并存在陶瓷基体中铁优先溶解的现象.

Materials Fabrication and Corrosion Behavior of NiFe2O4 Cermet Inert Anodes

The cermet inert anodes with the compositions of Cu-NiFe_2O_4 and Ni-NiFe_2O_4 were developed by classical powder metallurgical technique respectively. The corrosion behaviors of NiFe_2O_4-based inert anodes in Na_3AlF_6-Al_2O_3 melts were investigated. The results show that the corrosion behavior of cermet materials is consistent with thermodynamic calculations. To improve densification and electrical conductivity are difficult because copper has poor wetting characteristics to NiFe_2O_4 phase. The relative high porosity can lead to the oxidation of metals in Cu-NiFe_2O_4 cermets and electrolyte penetration into the anodes. The anode was badly swollen at the end of testing. The materials do not degrade during electrolysis via anodic dissolution of copper phase. Preliminary testing of 5%Ni-NiFe_2O_4 cermet materials show that the anodes have excellent performance in cryolite-based melts. Nickel has the tendency to anodic dissolve and ferrite has the tendency of incongruent dissolution.