To Achieve Epitaxy Thermal Spraying by Substrate Melting

Abstract

Abstract There have been recent efforts to expand the thermal spraying capabilities for novel corrosion resistant coatings for metal bipolar plates were produced by thermal spraying for proton exchange membrane (PEM) fuel cell applications. Recently, substrate heated by plasma gun or by external laser beam has been proposed to enhance the mechanical and thermal properties of the coatings. Studies were found that with sufficient substrate heating, substrate melting may happen. When droplets solidified on a thin liquid layer on the top of the substrate, conditions will be similar to crystal growth and Epitaxy film growth will be possible. It is therefore possible that using substrate melting as tool to promote epi-layer growth using plasma spraying. Difficulty is how to control the substrate temperature to cause substrate melting during droplet solidification. In this study we will propose a new idea for better temperature control on the substrate. The capability of epitaxy growth using thermal spraying will be investigated. Molybdenum droplets impact on an Aluminum substrate will be studied. A splat formation model including undercooling, nucleation, and non-equilibrium solidification will be used to study the possibility of the substrate melting and grain size distribution.