Corrosion of NiFe_2O_4-10NiO-based cermet inert anodes for aluminium electrolysis  

铝电解用NiFe_2O_4-10NiO基金属陶瓷惰性阳极的耐腐蚀性能(英文)

作　　者：何汉兵[1] 王原[1] 龙佳驹 陈照辉[1] 

机构地区：[1]中南大学冶金与环境学院,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2013年第12期3816-3821,共6页中国有色金属学报（英文版）

基　　金：Project (2012FJ6123) supported by the Project of Science and Technology of Hunan Province,China;Project supported by Post-Doctoral Foundation of Central South University,China;Project (CL12100) supported the Undergraduate Innovative Training of Central South University,China;Project (2282013bkso13) supported by Free Exploration Plan of Central South University,China

摘　　要：NiFe2O4-10NiO-based cermet inert anodes for aluminium electrolysis were prepared and their properties were investigated in a lab-scale electrolysis cell. The results show that the inert anodes exhibit good performance during electrolysis in molten salt cryolite at 960 °C, but according to the analyses of phase compositions and microstructures through XRD, SEM/EDX and metallographic analysis, the metal in the anodes is preferentially corroded and many pores are produced on the anode surface after electrolysis. The preferential dissolution of Fe in the NiFe2O4 phase may lead to the non-uniform corrosion of NiFe2O4 grains. Moreover, a dense protective layer of NiFe2O4-NiAl2O4-FeAl2O4 is formed on the anode surface, which originates from the reaction of Al2O3 dissolved in the electrolyte with NiO or FeO, the annexation of NiFe2O4-NiAl2O4-FeAl2O4 to NiO and volume expansion. Thus, the dense NiFe2O4-NiAl2O4-FeAl2O4 layer inhibits the metal loss and ceramic-phase corrosion on the surface of the cermet inert anodes.制备铝电解用NiFe2O4-10NiO基金属陶瓷惰性阳极,并在实验室电解槽中考察其电解腐蚀性能。结果表明,电解过程中虽然惰性阳极在960°C熔盐电解质中表现出优异的耐腐蚀性能,但采用XRD、SEM/EDX和金相分析其物相组成和微观结构后发现,电解后阳极中的金属相发生了优先腐蚀,在阳极表面产生大量孔洞。NiFe2O4相中的Fe元素的优先溶解可能导致NiFe2O4晶粒的不均匀腐蚀。溶解在电解液中的Al2O3与阳极中的NiO或FeO发生反应生成的NiFe2O4-NiAl2O4-FeAl2O4相对NiO相的吞并以及体积膨胀,阳极表面形成致密的NiFe2O4-NiAl2O4-FeAl2O4保护层。因此,致密的NiFe2O4-NiAl2O4-FeAl2O4保护层可以阻挡阳极表面金属相的损失和陶瓷相的腐蚀。

关 键 词：NIFE2O4-10NIO aluminium electrolysis inert anode CERMET CORROSION 

分 类 号：TG148[一般工业技术—材料科学与工程]