17(Cu-10Ni)-(NiFe2O4-10NiO)基金属陶瓷在铝电解过程中的相演变

摘要

17(Cu-10Ni)-(NiFe2O4-10NiO) cermets were prepared by cold pressing and sintering in nitrogen atmosphere,and tested as inert anode for aluminum electrolysis at 960 ℃ for 10 and 40 h,respectively. Microstructures and phase compositions of the as-sintered and post-electrolyzed samples were investigated. The impurity contents in the electrolyte and the cathode metal were detected in order to investigate the corrosion characteristic of the elements ofFe,Ni and Cu in the anode. A dense NiFe2O4 layer was observed on the surface of anode and thickened with prolonging the electrolysis time. In the newly formed dense ceramic layer,NiO phase disappeared as a result of being swallowed by NiFe2O4 phase,and the metal phase was oxidized during the electrolysis in which Cu element showed a higher dissolution rate than Fe and Ni elements. The formation process of the dense ceramic layer during the electrolysis was presented and explained by using the corrosion mode of the metal phase and the transformation mechanism from NiO phase to NiFe2O4 phase.%采用冷压气氛烧结制备17(Cu-10Ni)-(NiFe2O4-10NiO)金属陶瓷,并作为阳极在960℃下分别进行10和40 h的铝电解试验.对电解前后金属陶瓷的显微结构、物相成分进行分析检测.对电解质及阴极金属中的杂质含量进行分析,研究阳极组成中Fe、Ni和Cu元素的腐蚀行为.研究发现:在电解过程中,在材料表面形成NiFe2O4相致密层,该致密层随电解时间的延长而增厚.在NiFe2O4相致密层形成与增厚过程中,出现NiFe2O4相吞噬NiO相和金属相氧化的现象,金属陶瓷中Cu元素优先腐蚀溶解.并着重讨论NiFe2O4相致密层形成与增厚过程中金属相的腐蚀形式及NiO相向NiFe2O4相的转变机制.