研究以超重力辅助燃烧合成熔融铸造方法快速制备超高温氧化物共晶陶瓷,即,以Al/NiO/Y2O3/ZrO2为反应剂,通过诱发各组元间的燃烧合成反应,首先获得陶瓷和金属的混合熔体,随后利用2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,成功制备了Al2O3、钇铝石榴石(yttrium aluminumgarnet,YAG)、Y稳定ZrO2(yttria-stabilized zirconia,YSZ)共晶陶瓷块体材料Al2O3/YAG/YSZ。X射线衍射分析和微观组织观察表明所制备的共晶陶瓷由YAG,YSZ和α-Al2O3组成,其中α-Al2O3和YAG都为连续相且相互缠绕形成网络结构,而YSZ相尺寸为0.5μm,且以棒状或纤维状均匀分散在α-Al2O3和YAG相之间,该陶瓷块体材料的相对密度为97.50%,硬度为17.80GPa,断裂韧性为(5.50±0.90)MPa·m1/2。
The high temperature eutectic ceramics have been fabricated by combustion synthesis melt casting under ultra-high gravity field.With Al/NiO/Y2O3/ZrO2 as reagents,first the combustion synthesis reaction was ignited,and then the ceramic product could be completely separated from the metal melt via ultra-high gravity field because of the different densities.The as-separated ceramics developed into the Al2O3/YAG/YSZ eutectics during rapid solidification under ultra-high gravity field.The relative density of the ceramic sample is as high as 97.50%.XRD analysis and microstructure investigation show that the ceramic sample is composed of YAG,YSZ and α-Al2O3,in which the α-Al2O3 and YAG are entangled with each other and form a network structure.The YSZ,with diameter of 0.5 μm,is dispersed between the α-Al2O3 and YAG with the shape of rods or fibers.The Vickers hardness of the eutectic ceramic sam-ple is 17.80 GPa,and the calculated fracture toughness is as high as(5.50±0.90) MPa·m1/2.