烧结工艺对Ti(C,N)基金属陶瓷性能的影响

采用粉末冶金法制备Ti(C,N)基金属陶瓷,利用金相图像分析系统和扫描电镜观察陶瓷表面孔洞和微观组织形貌,分析了热处理和烧结气氛工艺对不同碳氮比的Ti(C,N)基金属陶瓷性能的影响.结果表明:真空烧结后的热处理工艺可使Ti(C,N)基金属陶瓷的横向断裂强度提高10%以上,硬度也有不同程度的提高,其中Ti(C0.5 N0.5)基金属陶瓷适合采用低压工艺处理,Ti(C0.7 N0.3)基金属陶瓷适合采用热等静压工艺处理.氮气气氛烧结中,Ti(C0.5 N0.5)基金属陶瓷在氮分压值为2kPa时的横向断裂强度达到最大值,而硬度变化不明显,这可归因于合适的氮分压阻碍了金属陶瓷内氮化物的分解,提高了材料的致密度,细化了晶粒组织.

Effect of sintering process on properties of Ti(C, N) cermets

Titanium carbonitride matrix cermets were prepared by powder metallurgical procedures.The surface pores and microstructure of cermets were observed by using metallurgical image analysis system and scanning electron microscopy(SEM),and the effects of heat treatment and sintering atmosphere on properties of Ti(C,N) matrix cermets with different carbon-nitrogen ratio were analyzed.The results show that the transverse rupture strength(TRS) of Ti(C,N) matrix cermets increases more than 10% after heat treatment,and the hardness increases with different degree too.The low pressing(LP) process is suitable for Ti(C_(0.5)N_(0.5)) matrix cermets and hot isostatic pressing(HIP) process is suitable for Ti(C_(0.7)N_(0.3)) matrix cermets.When sintered in nitrogen atmosphere,the maximum TRS value of Ti(C_(0.5)N_(0.5)) matrix cermets is obtained under the nitrogen partial pressure of 2kPa,while the variation of the hardness is not obvious,which can attribute to nitrogen partial pressure impeding the decomposition of nitride in cermets,increasing the density and refining grains.