原料中C/N原子比对TiCN基金属陶瓷组织结构和性能的影响

Effects of C/N atomic ratio in raw materials on the microstructure and properties of Ti(C,N)-based cermets

分别以Ti(C0.4,N0.6),Ti(C0.5,N0.5)和Ti(C0.7,N0.3)等3种TiCN粉末为原料,制备TiCN-25WC-10TaC-2Mo2C-7Ni-7Co金属陶瓷,研究TiCN原料中C/N原子比对TiCN基金属陶瓷组织结构、硬度、抗弯强度、韧性、磁学性能以及耐腐蚀性能的影响。结果表明,以Ti(C0.4,N0.6)为原料制备的TiCN基金属陶瓷中出现M6C型脱碳相(η相),导致材料的抗弯强度和韧性显著降低。以Ti(C0.7,N0.3)为原料制备的金属陶瓷为典型的弱芯环结构,具有最佳的力学性能,硬度(HV30)、抗弯强度和Palmqvist韧性分别为15.61 GPa,2294 MPa和11.29 MN·m^–3/2。随TiCN原料中C/N原子比降低,金属陶瓷的矫顽磁力和相对磁饱和均大幅降低。在pH=1的H2SO4溶液中的电化学腐蚀实验结果表明,采用Ti(C0.4,N0.6)和Ti(C0.5,N0.5)原料制备的金属陶瓷的耐腐蚀性能相近,采用Ti(C0.7,N0.3)原料制备的金属陶瓷的耐腐蚀性能显著降低。

Three kinds of TiCN-25WC-10TaC-2Mo2C-7Ni-7Co cermets were prepared from TiCN powders with different C/N ratio,i.e.,Ti(C0.4,N0.6),Ti(C0.5,N0.5)and Ti(C0.7,N0.3).The effects of C/N atomic ratio on the microstructure,hardness,transverse rupture strength,Palmqvist toughness,magnetic properties and corrosion resistance of TiCN-based cermets were investigated.The observation and analysis results show that there is a M6C type decarburization phase(ηphase)in the cermet with Ti(C0.4,N0.6)as the raw material,which results in a substantially decrease in transverse rupture strength and toughness.Microstructure of the cermet prepared from Ti(C0.7,N0.3)raw material shows a typical weak core-rim structure,which is accompanied by the best mechanical properties,i.e.,15.61 GPa for HV30,2294 MPa for transverse rupture strength and 11.29 MN·m^–3/2 for Palmqvist toughness.With the decrease of C/N ratio in the TiCN raw material,the coercivity force and relative magnetic saturation of cermet decrease rapidly.The results of electrochemical corrosion experiments in H2SO4 solution with pH=1 show that the corrosion resistance of cermets prepared from Ti(C0.4,N0.6)and Ti(C0.5,N0.5)is similar,and the corrosion resistance of cermets prepared from Ti(C0.7,N0.3)is significantly decreased.