A Novel Processing Route for Ni-doped Alumina Composites

作     者：JING Mao-xiang SHEN Xiang-qian ZHOU Jian-xin LI Dong-hong LI Wang-xing 

作者机构：School of Materials Science and Engineering Jiangsu University Zhenjiang 212013China Zhengzhou Research Institute of Chalco Henan Zhengzhou 450041 China 

出 版 物：《Chinese Journal of Aeronautics》 (中国航空学报（英文版）)

年 卷 期：2006年第19卷第B12期

页      面：55-61页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：Innovation Foundation of Jiangsu University(04CX01) 

主　　题：alumina-based composite Ni-coated alumina powder heterogeneous precipitation Ni dispersion 

摘      要：Alumina-based composites containing 0-15wt% Ni metallic phase were produced by hot press-sintering Ni-coated alumina powders. The Ni-coated alumina powders were prepared by the aqueous heterogeneous precipitation of alumina micro-powders and nickel sulfate salt followed by reduction process. The microstructural features and dispersion of Ni phase in Ni-coated alumina powders and the subsequent alumina-Ni cermets were investigated using scanning electron microscope （SEM）, X-ray diffractometer （XRD）, and transmission electron microscope （TEM）. The relative density of the hot press-sintered composites was measured with the Archimedes＇ method while the fracture strength and the fracture toughness were defined with the three-point bending method and the micro-indentation fracture method. In the formation of alumina-Ni cermets from sintered Ni-coated alumina powders, Ni phase to some extent limits the densification rate and stifles the coarsening and growing process of alumina grains. The Ni phase is found to be located at the interfaces and the triple-joint junctions of alumina grains which results into alteration of the fracture mode of alumina and its increased fracture strength and fracture toughness if compared with monolithic alumina.