(中南大學(xué) 粉末冶金國家重點實驗室，長沙 410083)
摘 要: 以NiO、Fe2O3和Nb2O5為原料，采用固相燒結(jié)法合成陶瓷粉體，通過等靜壓-氣氛燒結(jié)法制備Ni1-xNbxFe2O4 (x=0, 0.02, 0.05, 0.07, 0.10, 0.20)陶瓷試樣，并對其進行導(dǎo)電性能測試。通過XRD、SEM、EDX、FTIR和XPS等分析手段對材料的物相組成、顯微結(jié)構(gòu)和微區(qū)成分進行表征，研究Nb2O5摻雜對陶瓷材料顯微結(jié)構(gòu)和導(dǎo)電性能的影響。結(jié)果表明：Nb2O5摻雜抑制NiFe2O4基體中NiO相的出現(xiàn)，過量時生成FeNbO4相；適量摻雜(x=0.05)有利于消除晶界孔隙，提高陶瓷的燒結(jié)密度；與未摻雜試樣相比，摻雜Nb2O5的NiF2O4陶瓷材料的導(dǎo)電性均得到很大改善，其中摻雜量x=0.05的Ni0.95Nb0.05Fe2O4陶瓷試樣在1 233 K的電導(dǎo)率較純NiFe2O4的提高60%。
關(guān)鍵字: NiFe2O4；導(dǎo)電性能；物相組成；Nb2O5摻雜
（State Key Laboratory of Power Metallurgy, Central South University, Changsha 410083, China）
Abstract:The ceramic powders were synthesized by solid-state reaction method using nickel oxide, ferric oxide and niobium oxide as raw materials, and the Ni1-xNbxFe2O4 (x=0, 0.02, 0.05, 0.07, 0.10 and 0.20) ceramic were prepared by isostatic pressing-atmosphere sintering method. The electronic conductivity of ceramics was tested. The phase composition, microstructure and microarea composition of ceramics were analyzed by XRD, SEM, EDX, FTIR and XPS. The effects of Nb2O5-doping on the microstructure and electrical properties of ceramics were investigated. The results show that the appearance of NiO phase in NiFe2O4 matrix is restrained during Nb2O5-doping. And an impurity phase of FeNbO4 appears while excessive Nb2O5 is added. The right amount of doping (x=0.05) helps to eliminate the pores in grain boundaries and improves the sintering density of ceramics. Compared with the undoped samples, the conductivity performances of doped sample have been greatly improved. The conductivity of Ni0.95Nb0.05Fe2O4 sample increases by 60% compared with that of the undoped samples at 1 233 K.
Key words: NiFe2O4; electrical properties; phase composition; Nb2O5-doping
