原位生成TiB_2颗粒增韧SiC基复相陶瓷研究  

STUDY ON SiC MATRIX COMPOSITES TOUGHENED BY IN-SITU SYNTHESIZED TiB_2

作　　者：张国军[1] 何余[1] 金宗哲[1] 

机构地区：[1]中国建筑材料科学研究院

出　　处：《硅酸盐学报》1995年第2期134-140,共7页Journal of The Chinese Ceramic Society

摘　　要：提出一种新的方法制备ＳｉＣ－ＴｉＢ＿２颗粒复相陶瓷。通过Ｔｉ，Ｓｉ与Ｂ＿４Ｃ之间的化学反应在ＳｉＣ基体中原位生成ＴｉＢ＿２颗粒，获得的ＴｉＢ２颗粒一般在５μｍ以下，但发现有ＴｉＢ＿２颗粒团聚现象。其中ＳｉＣ－ＴｉＢ＿２３０％（ｖｏｌ）复相陶瓷的断裂韧性和三点弯曲强度分别比ＳｉＣ基体提高约１倍，达到４．５ＭＰａ·ｍ和４００ＭＰａ。认为ＴｉＢ＿２颗粒与ＳｉＣ基体之间热膨胀系数不同导致的残余应力场引起的裂纹偏转和形成的弹性桥联及摩擦桥联是ＳｉＣ－ＴｉＢ＿２颗粒复相陶瓷的主要增韧机理。A new process of preparing SiC-TiB_2 particulate toughened composite ceramics by in-situsynthesis is developed.TiB_2 particles are formed in-situ by chemical reaction between Ti,Si and B_4C,andthe particle;ize of TiB_2 is usually less than 5μm but there are TiB_2 agglomerates in the composites.Comparedwith hot-pressed monolithic SiC ,The fracture toughness and flexural strength of the composite containing30%(vol)TiB_2 increase one time approximately,i.e.,4.5 MPa·m and 400 MPa respectively.It is sug-gested that the main toughening mechanisms are crack defletion induced by residual thermal stresses in SiCmatrix and formation of elastic bridging and frictional bridging by TiB_2 particles.

关 键 词：碳化硅 硼化钛 增韧 复合陶瓷 

分 类 号：TQ174.758[化学工程—陶瓷工业]