Deposition of Workability-Enhancing Disposable Thick Fe Deposits on Fe-Si Alloy Sheets Using Thermal and Kinetic Spray Processes

Abstract

Fe-Si alloys are widely applied materials in industrial fields due to their magnetic properties. However, these alloys are difficult to manufacture due to the high oxidation affinity of Fe-Si alloys at high temperature; further, the permanence of the formed oxides (i.e., Fe2SiO4) degrade their workability. In order to solve this problem, disposable workability-improving thick coating layers were deposited on Fe-Si alloy substrates in this study using plain carbon steel wire and pure Fe powder via thermal and kinetic spraying processes. The resulting deposits were compared in terms of microstructure and mechanical properties. In thermal sprayed deposit, the oxides degraded mechanical properties, but were helpful for the deposition of a thick layer by restraining bending by thermally induced tensile residual stress. On the other hand, kinetic sprayed deposit showed better adhesive bond strength owing to the compressive residual stress. After a post heating, it was observed that the type of oxides was not affected by diffusion of Si elements from the substrate due to the limited diffusion length of Si elements. Imperfect chemical/ metallurgical bonding between the deposit and substrate was also observed. Further, mechanical properties of post heat-treated specimens were enhanced relative to the as-sprayed state.