Al_2O_3陶瓷基体中原位生成TiB_2和Ti（C，N）研究

STUDY ON IN SITU FORMATION OF TiB_2 AND Ti(C,N)IN Al_2O_3 CERAMIC MATRIX

采用原位反应法结合热压工艺制备Ａｌ＿２Ｏ＿３－ＴｉＢ＿２－Ｔｉ（Ｃ，Ｎ）复相陶瓷，用ＴｉＯ＿２，Ｂ＿４Ｃ，ＢＮ，Ａｌ及Ａｌ＿２Ｏ＿３为原料，通过组成设计可以制备出不同相组成及碳氮比的复相陶瓷。由ＳＥＭ及ＴＥＭ发现在Ａｌ＿２Ｏ＿３晶粒中分布着亚微米至微米级的近圆形Ｔｉ（Ｃ，Ｎ）颗粒，而在ＴｉＢ＿２晶粒中分布看纳米级的板状Ｔｉ（Ｃ，Ｎ）晶体，并对这种显微结构的形成机理及化学反应过程作了初步分析。

TiO_2,B_4c,BN,Al and Al_2O_3 are Used as raw materials, associated with the in-situ reaction and hot pressing method,to prepare Al_2O_3-TiB_2-Ti(C,N)composites with different phase composition and C/N ratios by different composition design.In the composite produced,submicro-to micron-size quasisphericaI Ti(C,v)particles are found by SEM,TEM,distributing in the Al;O3 grains,and platelet of Ti(C,N)of nanometer size distributing in the TiB_2 grains respectively. The formation mechanisms of these microstructures and the chemical reaction process are also discussed preliminarily.