Influence of Workpiece Materials on the Characteristics of the Layers by Electrical Discharge Coating

We investigated the influence of iron-based workpiece materials on the characteristics of the Si layers by electrical discharge coating. It was found that the chemical elements of the precipitations were uniformly dispersed in the layers on the workpieces containing precipitations a few micrometers in diameter. By contrast, voids occurred in the layer on the workpiece containing bigger precipitations because the precipitations that had not totally melted in the coating process were the starting points of the voids. In addition, the surface of the Si layer on FC250 was extremely rough, and the distribution of the chemical elements of the layer was inhomogeneous. However, the layer was amorphous, and the friction coefficient of the layer was lower than that of the workpiece.