【摘要】 利用热喷涂和等离子熔覆技术分别制备了镍基涂层,采用SEM、X射线衍射、显微硬度、失重分析法对空蚀前后的涂层进行了对比研究,并在旋转圆盘空蚀实验机上进行了空蚀实验。SEM结果表明,等离子熔覆涂层与基体结合为冶金结合,内部组织致密,缺陷少;热喷涂涂层由堆积的变形粒子组成,与基体多为机械结合,涂层具有层状叠加组织结构,其中孔隙较多。Ni基熔覆涂层表现出较好的耐空蚀性能,其失重量与对比不锈钢接近。X射线衍射分析空蚀后的熔覆涂层表面物相发生了变化,空蚀前后的熔覆涂层截面硬度表明,镍基涂层的在空蚀过程中出现了加工软化。热喷涂涂层由于内部结合力较低,特别容易被空蚀微射流或冲击波过程所破坏。更多还原

【Abstract】 The properties of cavitation erosion of two kinds of Ni based coatings,which were deposited by means of active combustion-high velocity air-fuel(AC-HVAF) spraying and plasma cladding technology,respectively,were studied using rotating disc cavitation equipment.SEM,X-Ray diffraction,micro hardness,mass loss analysis were employed in examining the structure and phases of the coatings before and after cavitation erosion.The results show that the microstructure of plasma clad coating is compact with less defects and metallurgical bonding between coating and substrate is observed.The coating deposited by thermally spraying exhibits the microstructure with deformed and un-molten particles and many pores defects,and mechanical bonding between coating and substrate isobserved.Cavitation erosion resistance of the coating deposited by plasma cladding is superior to that sprayed by AC-HVAF method for its compact metallurgical structure and less amounts of pores.It is found that working softening occurs in the plasma clad coating in cavitation erosion process and some new phases form after cavitation.更多还原