【摘要】 采用Pechini法,成功制备了Mn0.43Ni0.9CuFe0.67O4纳米粉体。聚合前驱体在400~700℃下煅烧,采用热重-差热分析(TG-DTA)、红外光谱(IR)、X射线衍射(XRD)、粒度分布和扫描电镜(SEM)对产物进行了表征。煅烧后,在900~1200℃烧结,测试了烧结陶瓷的电学性能参数:电阻率ρ和材料常数B。结果表明,粉体的分解温度为300℃,由无定形相开始结晶;晶体结构不同于传统NTC材料的单一尖晶体结构,而是尖晶石相和单斜CuO相组成的固溶体;单斜CuO相对陶瓷的电学性能有较大影响。烧结性质表明,最佳烧结温度为1100℃,致密度为96%,2ρ5℃为600Ω.cm,材料常数B25℃/50℃为2000。更多还原

【Abstract】 Mn0.43Ni0.9CuFe0.67O4 nano-powders were synthesised by the Pechini method for the first time.A spinel-type phase,with a solid solution,was attained from calcining of the polyme-rized gel precursor at 400～ 700 ℃.The thermal evolution,surface morphology,and structural behavior were studied by TG-DTA,SEM,XRD and FT-IR.The electrical properties,the resistivity ρ and the materials constant B value,were also studied after sintering at 900～1200 ℃.It is found that the material decomposes upon heating above 300 ℃.The monoclinic structure of CuO is found to be coexistent with the spinel-type phase in both the calcined powders and the sintered ceramics.The electrical properties are deeply affected by the crystal phase of CuO.The ceramics sintered at 1100 ℃ shows the best electrical properties as well as the density,of which the relative density is about 96%. The ρ25 ℃ is about 600 Ω·㎝ and B25 ℃/50 ℃ is about 2000.更多还原