TaC陶瓷的强化烧结

TaC ceramic prepared by enhanced sintering technology

为探索开发低成本TaC陶瓷强化烧结制备工艺,以C、Ta和TaC粉末为原料,经成形、常压烧结制备出TaC陶瓷。结果表明:以C与Ta单质粉末为原料反应烧结时,发生自蔓延反应,产物疏松多孔,不能获得致密TaC陶瓷;纯TaC粉末在2 100℃烧结时为多孔烧结体,相对密度约为78%,孔隙大、量多且相互连通;采用添加少量C与Ta粉末强化烧结TaC坯体时,在2 100～2 300℃可以制备相对密度为91%以上的TaC无裂纹陶瓷;随强化烧结温度提高以及C、Ta粉末添加量的增加,陶瓷晶粒变粗,致密度提高。讨论了添加少量C与Ta粉末在TaC陶瓷烧结过程中的强化烧结机理。

TaC ceramics were prepared with C, Ta and TaC powders by shaping and sintering under ordinary pressure to explore a newly enhanced sintering technology for preparing TaC ceramics. The microstructures of specimens were studied by metallography and scanning electron microscope. The results indicate that TaC ceramics sintered from C and Ta powder at high temperature is porous because of fierce self-propagation high-temperature synthesis; TaC ceramics sintered with pure TaC powder at 2100 ℃ gets a relative density of 78% and a porous structure with large amount of holes linking together; crack free TaC ceramics with relative density more than 91% could be prepared from TaC green compact added with small amount of C and Ta powders and enhanced sintering between 2100℃ and 2300℃. With the increasing of enhanced sintering temperature and the content of additive, the granularity will grow up and the pore in.the ceramics is well-distributed. Finally TaC ceramic enhanced sintering mechanism added with small amount of C, Ta powder was discussed.