HVOF喷涂WC-12Co粒子在不同基体上的沉积行为

Deposition Behavior of WC-12Co Particles on Different Substrates Sprayed by HVOF

采用超音速火焰喷涂方法(HVOF)在铝合金、紫铜和不锈钢基体上制备WC-12Co扁平粒子,利用扫描电子显微镜(SEM)对半熔化两相粒子的扁平行为及与基体结合状况进行观察分析,并将半熔化WC-Co粒子与基体碰撞模型简化为液相的Co粒子和固相的WC颗粒分别与基体相互作用的过程,通过改进后的数学模型计算基体与粒子的相对形变比λ。结果表明:HVOF喷涂WC-12Co扁平粒子在铝、铜和不锈钢基体上分别呈现半球状、薄饼状和溅射状形貌,不同形貌的扁平粒子形变比λ不同。与半球状(λ>1)和溅射状(λ<1)扁平形式相比,形成薄饼状(λ≈1)的扁平粒子时粒子与基体均发生适度的变形,有助于增加粒子与基体的有效结合面积,提高结合强度。

WC-12 Co particles were deposited on aluminum,copper and stainless steel substrates by High Velocity Oxy-fuel（HVOF）process.Both the surface and the cross-sectional morphology of the two-phase semi-molten particles were observed by Scanning electron microscopy（SEM）.The collision model of the two-phase particles with matrix was simplified as the process interacting with substrate of liquid phase Co and solid phase WC,and an improved mathematical model was established to calculate the relative deformation ratio λ of the substrate to the splat.Results show that WC-Co particles deposited on aluminum,copper and stainless steel substrates exhibit hemispherical-like,pie-like and sputtering-like morphologies,respectively,and different shaped WC-Co particles have different λ values.Compared with forming hemispherical-like（λ〉1）and sputtering-like particles（λ〈1）,moderate deformation occurs in both particles and substrates when pie-like（λ=1）particles are formed,which is beneficial for increasing the effective contact area between particles and the substrate,thus improving the bond strength.