高温环境下超声深滚静压力对金属陶瓷涂层微观组织结构的影响

Effect of Ultrasonic Deep Rolling Static Pressure on Microstructure of Cermet Coating at High-Temperature Environment

为提高金属陶瓷涂层与基体的结合性能,通过对Ni-WC金属陶瓷涂层实施电阻加热和超声深滚耦合处理,探究高温环境下不同超声深滚静压力对Ni-WC金属陶瓷涂层微观组织结构的影响。通过扫描电镜、X射线衍射仪和JADE软件对改性金属陶瓷涂层进行测试,通过分析改性金属陶瓷涂层的表面微观形貌、晶粒尺寸和表面残余应力,探讨改性金属陶瓷涂层结合强度,用ImageJ软件评价改性金属陶瓷涂层孔隙率。结果表明:高温下超声深滚提高了涂层表面光洁度,细化了晶粒,引入了残余压应力,提高了涂层综合性能;随静压力的增大,改性金属陶瓷涂层的表面微观形貌得到明显改善,表面残余压应力逐渐增大,涂层与基体之间形成了部分冶金结合,结合强度大大提高;静压力较大时出现了物相的转变,且随静压力的增大,其孔隙率也逐渐减小。

In order to improve the bonding performance between the cermet coating and the substrate,the Ni-WC cermet coating was subjected to the coupling treatment of resistance heating and ultrasonic deep rolling to explore the effect of different ultrasonic deep rolling static pressures on the microstructure of the Ni-WC cermet coating at high temperature environment.The modified cermet coating was tested by scanning electron microscope,X-ray diffractometer and JADE software,and the bonding strength of cermet coatings was investigated by analyzing the surface micromorphology,grain size and surface residual stress of the modified cermet coating.The porosity of modified cermet coatings was evaluated by ImageJ software.Results show that ultrasonic deep rolling at high temperature improves the surface finish of the coating,refines the grains,introduces residual compressive stress,and improves the comprehensive performance of the coating.With the increase of static pressure,the surface micro-morphology of the modified cermet coating is significantly improved,the surface residual compressive stress gradually increases.A partial metallurgical bond is formed between the coating and the substrate,so the bonding strength is greatly improved.The phase transition occurs when the static pressure is high,and the porosity gradually decreases with the increase of static pressure.