表面熔融粒子结构对超音速火焰喷涂层结合性能的影响

Effects of Surface Melting Particles on Adhesion of Cermet Coatings by High Velocity Oxy-Fuel Spraying

探讨了在超音速火焰喷涂 (HVOF)过程中所形成的表面金属层熔化而芯部陶瓷相不熔化的表面熔融粒子结构 .研究了这种粒子结构对HVOF涂层结合性能的影响规律 ,发现固态颗粒的密度及体积分数与结合强度有直接的对应关系 .提出了综合考虑固态粒子密度、体积分数及速度 ,表征半熔结构状态对涂层结合性能影响的有效固相质量和有效固相动能两个参量 .有效固相质量定义为固态粒子密度和其体积分数平方的乘积 ,有效固相动能定义为有效固相质量与粒子速度平方的乘积 .试验结果表明 。

The conglomerate structure of surface melting particles, in which the metallic out-layer of refractory particles (WC, SiC, TiC, etc.) are melted during spray process, is formed by using high velocity oxy-fuel(HVOF) spraying. The effect of solid-liquid two-phase structure on the adhesive behavior of HVOF coatings is investigated. It is found that the adhesive strength of HVOF coating is positively related to the density and volume fraction of solid phase in sprayed particles. Two parameters to characterize the two-phase structure in HVOF spraying are proposed by taking the density, volume fraction, and velocity of solid particles into account. The two parameters are named the effective mass factor of solid phase and the factor of effective kinetic energy of solid phase, respectively. The former is defined as the product of density and square of volume fraction of solid particles, and the latter is the product of the one and square of particle velocity. The correlation between the parameters and adhesive strength of the coating shows that the adhesive strength increases with the increase in the effective kinetic energy of solid particles.