自反应喷射成型复相陶瓷中的飞行粒子燃烧反应研究

Research on Combustion Reaction of Flying Particles during Process of Self-reactive Spray Forming Multi-phased Ceramic

基于Ti-B4C-蔗糖体系,自反应喷射成型了Ti(C,N)-TiB2复相陶瓷坯件,通过淬熄试验和碰撞试验,研究了喷射粒子的飞行燃烧与自蔓延反应特性.研究表明,在喷射过程中,喷射粒子在火焰场中经历受热、表面熔融、反应转化过程形成陶瓷熔滴;反应始于Ti的熔化,在整个喷射过程中伴有Ti的氮化和氧化;各喷射粒子独立地构成微自蔓延反应单元,整个喷射体系及过程不存在宏观的燃烧波和燃烧界面的移动;每个喷射粒子按自己的飞行轨迹,在不同时段发生自蔓延反应与转变,反应与转化程度主要取决于喷射粒子的尺寸与温度,粒度适宜、温度较高的粒子均转变为陶瓷液滴;所得喷射沉积坯件的致密度为97.7%,显微硬度为2029HV0.2,断裂韧性达6.0MPa.m1/2.

Based on the SHS reaction of Ti-B4C-sucrose system, Ti（C, N）-TiB2 ceramic preforms were prepared by self-reactive spray forming technology. The characters of combustion and SHS reaction during me spray process were investigated by water-quenching experiments and collision experiments. The results show that during the spray process, the sprayed particles transform into ceramic beads after the process of heating, surface melting and reacting. The reaction begins with the melting of titanium. And the nitridation and oxi- dation of titanium go with the whole spray process. Each sprayed particle acts as an individual reactive unit, and there is no macro combustion wave and surface moving in the system. Each particle reacts and transforms in the different time by its own flight track. The transforming extent of the sprayed particles depends on their temperature and size. The sprayed particles with optimal size and high temperature can all transform into ceramic beads. The relative density, micro-hardness and fracture toughness of the sprayed preforms are 97.7% ,HV02 2029 and 6.0MPa · m^1/2 respectively.