以MH_2(M=Ti,Zr)为原料反应烧结制备MB_2-SiC复相陶瓷

Reactive Sintering MB_2-SiC(M=Ti,Zr)Composites Using MH_2 as Raw Materials

分别以TiH2,ZrH2为原料,结合原位反应与脉冲电流辅助烧结制备了TiB2-SiC及ZrB2-SiC复相陶瓷。研究发现,所制备的复相陶瓷表现出一定的织构化现象,TiB2及ZrB2晶粒在反应烧结过程中其(001)面沿垂直压力和电流方向生长。金属氢化物粉体的粒径大小对复相陶瓷的致密化及微结构有较大影响:粒径越小越有利于陶瓷的致密化和硼化物晶粒的定向生长。由于金属硼化物的定向,复相陶瓷的机械性能表现出各向异性。TiB2-SiC复相陶瓷具有较高的断裂韧性,最高可达7.3 MPa.m1/2,而ZrB2-SiC复相陶瓷具有更高的抗弯强度(937 MPa)。

MB2-SiC （M =Ti,Zr） composites were prepared by reactive pulsed electric current sintering using MH2 as raw materials. The results indicated that the composites had a slightly textured structure with MB2 grains oriented with their （001） planes perpendicular to the direction of pressure and DC current. Fine MH2 powders improved densification and orientation of MB2 during reactive sintering process. Due to the orientation of MB2 grain, the MB2-SiC composites exhibited mechanical anisotropy. The TiB2-SIC composites showed high fracture toughness with the highest＇ value of 7.3 MPa . m^1/2 and the ZrB2-SiC composites had a high flexural strength with the value of 937 MPa, respectively.