The influence of powder characteristics on mechanical properties of Al_2O_3-TiC-Co ceramic materials prepared by Co-coated Al_2O_3/TiC powders

摘要

Ultrafine Al_2O_3-TiC-Co (ATC) ceramic is prepared in order to improve the bending strength and fracture toughness of ceramic materials. The ultrafine Co-coated Al_2O_3 and TiC powders have been synthesized by electroless plating at room temperature, and the composite powders were sintered by hot-pressing to compact ATC samples. The average bending strength, average hardness and average fracture toughness values of ATC ceramic with different particle sizes and Co contents were investigated. The toughening mechanism of the ultrafine ATC ceramic was studied by transmission electron microscopy (TEM) and ceramic performance testing methods. The results show that the relative density, bending strength and fracture toughness values increase remarkably with the increase of Co content. The ultrafine grain of original powders is beneficial to improve the relative density, strength and toughness values of ATC ceramic. The Co phase hinders the growth of ATC ceramic grains during sintering. The Co phase forms a three-dimensional mesh skeleton structure during sintering, improving the fracture toughness and strength of the composite ceramic