Fabrication of high-quality platinum coating using explosive welding technology and its microstructure evolution mechanisms

Abstract

Obtaining high-quality Pt coatings remains a challenging task. Here, explosive welding was attempted to prepare Pt coatings on a steel plate, and the complex interfacial phenomena of the achieved Pt/Fe joints as well as the governing mechanisms were carefully investigated by multi-scale microstructure analyses and smoothed particles hydrodynamics simulations. The results demonstrated that the self-development explosive welding was a suitable method for preparing Pt coatings, featuring a desirable undulating metallurgical interface. Two types of transition regions, namely the isolated zones and continuous layers, were formed at the wave interface, and their formation mechanisms were revealed. Besides, special attention was given to the frequent formed elliptic void in the isolated transition regions, and its formation mechanism was found to be combined actions of excessive shear instability and rapid cooling process. The multi-area EBSD analyses revealed diverse grain structures near the interface, such as formation of columnar grains in isolated transition region and small equiaxed grains in continuous melting layer. These grain characteristics provide strong supports for the interface formation mechanisms developed in this paper. Thus, this work enables to provide a new perspective for Pt coating preparation and improve the understanding of explosive welding process behavior.