导电性和耐蚀性
(中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 在氧分压约为100 Pa的氮气氛下烧结制备了掺杂Y2O3、Yb2O3 的10Cu-(NiFe2O4-10NiO)金属陶瓷，并对其进行导电性能测试和10 h (Na3A1F6-Al2O3 体系中)铝电解实验。采用XRD、SEM 和EDS分析稀土氧化物以及其与陶瓷基体反应产物的分布，考查电解实验后材料表层显微结构变化尤其是金属相的流失情况，评价稀土氧化物的添加对金属陶瓷电解初期腐蚀行为的影响。结果表明：掺杂稀土氧化物均使NiO相呈连通迹象，掺杂Yb2O3 金属陶瓷晶粒较未掺杂的粗大，其与陶瓷相反应生成物成点线状分布于NiFe2O4 相晶界，Y2O3 与陶瓷相反应生成物则分布于NiO与NiFe2O4相间；所制备材料具有半导体特征，随着稀土氧化物的掺杂，材料导电性呈下降趋势；掺杂稀土氧化物尤其是Yb2O3有利于提高材料的耐蚀性能。
关键字: 铁酸镍；导电性；耐蚀性；稀土氧化物
10Cu-(NiFe2O4-10NiO) inert anode doped Yb2O3 or Y2O3
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:10Cu-(NiFe2O4-10NiO) cermets doped Y2O3, Yb2O3 were prepared by sintering in the nitrogen atmosphere with oxygen partial pressure of about 100 Pa. The electronic conductivity of cermets was tested and 10 h (Na3A1F6-Al2O3 system) aluminum experiments were carried out. The distributions of rare earth oxides and the reaction products with ceramic matrix were analyzed by XRD, SEM and EDS. The effects of rare earth oxides on the corrosion resistance of cermets were evaluated by the change of microstructure of the anode surface after electrolysis, particularly the loss of metal phase. The results show that the NiO phase became more continuous after doping. The grains coarsen after doped Yb2O3 than undoped and the reaction products phase distributes in the NiFe2O4 grains boundary in the term of point line. However, the reaction product of Y2O3 and ceramics phase distributes in the NiO and the NiFe2O4 grain boundary. The prepared material has semiconductor characteristics and the electronic conductivity decreases with the rare earth oxides doping. Rare earth oxides doping help to improve the corrosion resistance of materials, particular Yb2O3.
Key words: NiFe2O4; conductivity; corrosion resistance; rare-earth oxide
