研究一种大块致密Al2O3/YAG/YSZ三元共晶陶瓷的快速制备新技术,以Al/Fe2O3/Y2O3/ZrO2为反应剂,通过诱发各组元间的燃烧合成反应,首先获得陶瓷(Al2O3/YAG/YSZ)和金属(Fe)的混合熔体;随后利用两种熔体的密度差异,在超重力场中实现陶瓷熔体和金属熔体的彻底分离和凝固。在超重力场作用下,先凝固的陶瓷相局部沉陷到金属熔体中,并受到金属熔体对之施加的接近2MPa的瞬态等静压力,因此得以实现完全致密化。微观结构分析表明,所获得的三元共晶陶瓷的相组成和晶粒形貌沿超重力方向呈现明显的梯度渐变特征。
A new method of rapid preparation for compact bulk Al2O3/YAG/YSZ ternary eutectic ceramics was researched.With Al/Fe2O3/Y2O3/ZrO2 as starting materials,the combustion synthesis reaction of Al/Fe2O3 was ignited,and then the molten compounds consisting of ceramics(Al2O3/YAG/YSZ) and metal(Fe) were achieved;afterwards the complete separation of ceramics melt from Fe melt and the solidification of the ceramics were realized under ultra-high-gravity field.The previously-solidified ceramics partially sank into the Fe melt,where the ceramics was forced to be entirely solidified by the instantaneous isostatic pressure on the verge of 2 MPa.The microstructure analysis results show that phase composition and morphology of grains of the obtained Al2O3/YAG/YSZ ternary eutectic ceramics have clearly gradient character along the ultra-high-gravity direction.