金属添加方式对NiFe基/NiFe_2O_4金属陶瓷微观组织的影响

Effect of Metal-adding Method on Microstructure of NiFe Base/NiFe_2O_4 Cermet

采用模压真空烧结法制备了2种金属陶瓷。差热分析、X射线衍射和扫描电镜结果表明:金属相加入方式对陶瓷的结构和组成有较大影响;当Al以单质形式加入时,Al会完全改变NiFe2O4原有尖晶石相,形成新尖晶石相,同时,这种加入方式会导致金属各元素的局部分布不均匀;当Al以合金化形式加入时,由于合金化后Al的扩散得到了较好地控制,没有改变原有陶瓷成分。2种金属陶瓷中的陶瓷相在高温烧结中都不稳定,都出现了离解现象。

Two kinds of cermet were prepared by vacuum sintering after die pressing. After being analyzed by differential thermogravity analysis(DTA), X-ray and scanning electron microscope(SEM), it is found that the form of adding metals has great effects on the microstructure and composition of ceramics. When Al is added as simple substance, the composition of ceramics is completely changed and a new spinal ferrite is formed. In the meantime, it led to nonuniform distribution of the elements in sample. When Al alloyed is added, the immigration of Al alloyed could be well controlled and the primitive ceramic isnt changed. The ceramic in two kind of cerments is unstable during sintering because the ceramic disassociates at elevated temperature.