以聚碳硅烷包覆B_4C为原料温压-烧结原位制备SiC/B_4C复相陶瓷

SiC/B_4C Multiphase Ceramics Using Polycarbosilane-Coating B_4C as Raw Materials Prepared In-suit by Warm Pressing and Sintering

以聚碳硅烷（PCS）包覆B4C粉为原料,分别在300℃、50 MPa下温压成型和800 MPa下冷等静压成型,而后将压坯置于氩气气氛保护下在1 200℃保温2 h,再在1 800-2 000℃下真空烧结3 h,原位反应制备出SiC/B4C复相陶瓷;研究了它的相对密度、物相组成和显微结构。结果表明：温压工艺比冷等静压工艺能得到更高密度的复相陶瓷;含15%SiC的温压压坯在烧结3 h后得到复相陶瓷的相对密度大于93%;复相陶瓷由B4C和SiC相组成,SiC相均匀分布在B4C颗粒界面上。

B4C/SiC pellets were prepared by warm pressing of polycarbosilane-coating boron carbide powder at the temperature of 300 ℃ under the pressure of 50 MPa,and cold isostatic pressing under the pressure of 800 MPa,respectively.The samples were then kept warm at 1 200 ℃ for 2 h in flowing Ar,with subsequent sintering for 3 h between 1 800 and 2 000 ℃ in vacuum.Relative densities,phases and microstructures of the multiphase ceramics were investigated.The results show that the multiphase ceramics prepared by warm pressing（WP） had higher density than that by cold isostatic pressing（CIP）.The multiphase ceramics with maximum relative density was achieved after the warm pressing green bodies containing 15% SiC sintered for 3 h,and its relative density was more than 93%.The multiphase ceramics consisted of B4C and SiC and SiC phases distributed uniformly on the B4C particles interface.