电爆喷涂粒子的约束调控机制及对沉积行为的影响

Regulation Mechanism and Effect on Deposition Behavior of Constraint Electro-explosive Spraying Particles

摘要:

采用对喷涂粒子进行槽内约束的电爆喷涂方法，研究了喷涂粒子在垂直槽中的约束调控机制及其沉积行为。结果表明：约束深度达20mm时，即喷涂距离为丝径的100倍时，仍可获得连续、均匀的涂层。约束宽度从6mm减小至2mm，涂层表面呈现出由粗糙的“丘壑状”形貌向均匀的“薄饼状”形貌逐渐过渡的演变趋势，且涂层厚度显著提高；能量密度从57J/mm3提高至152J/mm3，同样可提高涂层厚度并改善涂层均匀性。对喷涂粒子进行收集，发现减小约束宽度和提高能量密度均可有效细化喷涂粒子并使喷涂粒子粒径分布更加均匀。分析认为，由焦耳加热导致的“热膨胀效应”和击穿电弧伴生的“压力效应”共同决定电爆冲击波和喷涂粒子的形成，并随能量密度和约束参数的变化，对喷涂粒子表现出不同的约束调控作用，使其沉积行为产生显著差异。

Abstract:

The regulation mechanism and deposition behavior of sprayed particles in vertical groove were studied by means of groove constrained electro-explosive spraying. The results show that when the constraint depth reaches 20 mm, i.e. the spraying distance is 100 times of the wire diameter, the continuous and uniform coatings can still be obtained. With the constraint width decrease from 6mm to 2mm, the morphology of coating surface changed from "Hill-like" to "pancake-like"，and the coating thickness increases significantly; Increasing energy density from 57J/mm3 to 152J/mm3 can also improve coating thickness and uniformity. By analysis the collected spraying particles, it was found that reducing the constraint width and increasing the energy density can effectively refine the spraying particles and make the particle size distribution more uniform. It is concluded that the "thermal expansion effect" caused by Joule heating and the "pressure effect" associated with breakdown arc can work together to regulate the sprayed particles with the change of energy density and constraint parameters, which will resulting in different deposition behavior.