摘要
采用超重力场燃烧合成技术,以Ti+B4C为主反应体系,同时辅以不同含量的CrO3+Al增强体系,制备出不同Cr含量的TiC-TiB2复合陶瓷。XRD、FESEM与EDS分析表明,所得TiC-TiB2复合陶瓷主要由大量细小的TiB2片晶、TiC球晶构成,富Cr金属相多与TiB2片晶交织在一起。随着CrO3+Al含量增加,体系绝热温度升高,TiC-TiB2复合陶瓷中富Cr金属相体积分数逐渐增加。分析认为,超重力场下燃烧反应完成后,得到Ti-Cr-C-B合金液相,在冷却凝固过程中,TiC率先形核析出,TiB2随后析出,Cr及少量未反应Ti最后析出,并对TiB2片晶形成的骨架结构进行补缩,从而提高了TiC-TiB2复合陶瓷的致密性。
TiC-TiB2 composite ceramics with different Cr content were prepared by combustion synthesis in high gravity field using Ti+B4C as the primary reactive system assisted by different contents of CrO3+Al as the enhancement system.XRD,FESEM and EDS results show that the prepared composite ceramics are mainly composed of many fine TiB2 platelet grains and TiC spherical grains,and most Cr-rich metal phase intertwines with TiB2 platelet grains.With the content of CrO3+Al increased,system adiabatic temperature rises,and volume fraction of Cr-rich metal phase in TiC-TiB2 composite ceramic increases.It is supposed that Ti-Cr-C-B alloy liquid is the product of combustion reaction in high gravity field.During cooling and solidification of the alloy liquid,TiC nucleates and precipitates at first and then TiB2 precipitates.Finally,Cr and a small amount of unreacted Ti precipitate to fill the shrinkage cavity in the skeletal structure of TiB2 platelet grains and thereby increase the density of TiC-TiB2 composite ceramics.
出处
《稀有金属与硬质合金》
CAS
CSCD
北大核心
2015年第4期38-42 50,50,共6页
Rare Metals and Cemented Carbides
基金
国家自然科学基金(51202293)
军械工程学院科研基金(YJJXM12044)
军械工程学院车辆与电气工程系基金(CDX-K08-13)