超音速火焰喷涂TiB_2-40Ni35A金属陶瓷涂层的组织结构与性能

Microstructure and Corrosion Resistance of TiB_2 Reinforced 40Ni35A Cermet Coating Deposited by High Velocity Oxygen Fuel Spraying

为了制备耐热震和耐熔融金属腐蚀的金属陶瓷材料,通过机械合金化技术制备TiB_2硬质相增强Ni基金属陶瓷粉末,将其超音速火焰喷涂在Q235钢表面制成TiB_2-40Ni35A金属陶瓷涂层,并对其形貌、物相、孔隙率、结合强度、硬度、耐热震及耐熔融Al-12.07%Si腐蚀性能进行研究。结果表明:涂层组织致密、孔隙率仅为0.281%,物相主要为TiB_2和Ni;涂层的结合强度为64 MPa,硬度为(446.7±85.6)HV_(3 N);经过60次热震后,涂层中未发现明显的裂纹;经过60 h熔融Al-12.07%Si腐蚀后,涂层中未发现明显裂纹,仍与基体结合良好。

TiB_2-40Ni35A powders with hard TiB,as the reinforcing phase were fabricated by mechanical alloying.As- prepared TiB-,-40N135A powders were sprayed on Q235 steel substrate by high velocity oxygen fuel spraying to afford TiB_2-40Ni35A cermet coaling so as to improve the abrasive wear resistance and corrosion resistance of the steel substrates.The microstructure and phase composition of the cermet coating w-ere analyzed,and its microhardness,themial shock resistance and corrosion resistance in molten Al-12.07%Si were investigated.Results showed that TiB_2-40Ni35A cennet coating had dense microstructure and low porosity of only0.281%,and it was mainly composed of TiB,and Ni.Besides,as-prepared TiB_2- 40Ni35A cermet coating exhibited a bonding strength of 64 MPa and a hardness of(446.7 ± 85.6) HV_(3N).After60 cycles of themial shock tests and 60 h of conosion tests in the molten Al-12.07%Si,the TiB_2-40Ni35A cennet coating was still free of cracks and retained good adhesion to the steel substrate,which indicated that the cermet coating exhibited excellent themial shock resistance and corrosion resistance as well.