燃烧合成Co（Ti）-Al2O3金属陶瓷的组织与性能

利用低放热Al-TiO2反应体系部分取代高放热Al-CoO反应体系,并加入适量的稀释剂Al2O3吸收反应热量,通过热爆燃烧合成结合致密化工艺制备了铁磁性Co(Ti)-Al2O3金属陶瓷。研究表明,Co(Ti)-Al2O3金属陶瓷中随着Al-TiO2体系的增加,燃烧反应温度降低,金属相尺寸减小,分布更均匀,同时在金属相与基体之间形成过渡区域,提高了界面结合。Co(Ti)-Al2O3复合材料的饱和磁化强度随着金属Co含量增加而增加,最高可达到37.2849Am2/kg,而矫顽力在3997.6～5615.4A/m范围内变化,介于软磁体和硬磁体之间。

Microstructures and Properties of Co(Ti)-Al2O3Cermets Prepared by Combustion Synthesis

The ferromagnetic Co(Ti)-Al2O3 cermets were prepared by combustion synthesis in thermal explosion mode associated with densification technique.The reaction temperature was controlled by partial replacement of high-exothermic reaction system Al-CoO by low-exothermic Al-TiO2 and by proper content of Al2O3 diluents adding for the purpose of heat absorbing.The results show that along with the increasing of adding Al-TiO2 system in the reactant mixtures,the combustion temperature of preparing Co(Ti)-Al2O3 cermets decreases,so that the metal phase shows smaller dimension and more homogeneous dispersion;meanwhile,a transitional region occurs between metal and ceramic phases,which increased the phase interfacial strength.The saturation magnetization of Co(Ti)-Al2O3 cermets increases with the increasing of Co content in metal phase and the top of Ms is 37.2849Am2/kg while the coercive force changes from 3997.6A/m to 5615.4A/m,which means the magnetic property of this series of composites is between soft-magnetic and half-hard-magnetic.