无压烧结制备纳米复合碳化硅陶瓷

PRESSURELESS SINTERING OF SILICON CARBIDE NANOCOMPOSITE CERAMICS

以水基喷雾造粒而成含5%(质量分数)纳米氮化钛(TiN)颗粒的碳化硅(SiC)造粒粉为原料,采用无压烧结制备纳米复合SiC陶瓷。分析了烧结温度及保温时间对复合陶瓷烧结特性与显微结构的影响规律。结果表明:采取二步烧结可以实现SiC陶瓷在晶粒不明显长大的前提下实现致密化,二步烧结,即先升温到1950℃保温15min后迅速降至1850℃烧结1h,制备的SiC陶瓷具有较高收缩率、较低质量损失以及较高的致密度;纳米TiN颗粒加入后能与基体(SiC,Al2O3)部分发生反应生成TiC和AlN,明显改善SiC陶瓷的烧结性能,获得等轴状、细晶显微结构和优越的力学性能。

With silicon carbide （SiC） granulation powder containing 5% in mass nano-titanium nitride （TiN） particles prepared by spray drying technique as starting material,SiC nanocomposite ceramics were prepared using pressureless sintering.The effects of sintering temperature and time on the sintering behaviors and microstructure of composite ceramics were studied.The results show that the silicon carbide ceramics can achieve high densification while crystals do not grow up obviously by two-stages sintering.The SiC nanocomposite ceramic sintered at 1 850 ℃ for 1 h after at 1 950 ℃ for 15 min has higher contractiveness,lower mass loss and higher relative density.The nano-TiN particles could partly react with matrix （SiC and Al2O3） to produce TiC and AlN,which obviously enhances the sintering behaviors of SiC ceramics and obtains the silicon carbide ceramics with fine microstructure,equiaxed crystals,and predominant mechanical properties.