Characterization and mechanical properties of stainless steel coatings deposited by HVOF on ZE41 magnesium alloy

Abstract Stainless steel coatings have been applied on the surface of ZE41 magnesium alloys using High Velocity Oxygen-Fuel (HVOF) as deposition technique to improve their surface features. The coating characteristics (thickness, continuity, homogeneity and porosity), as well as their fracture behavior, have been correlated with the spraying parameters used, mainly the number of layers and spraying distance, and with the microstructure and presence of oxides in the coatings. The fracture behavior has been studied using an in situ scanning electron microscopy bending test. This test allows the observation of the crack progression and records the load-displacement curve. In all coatings, the crack progression occurred through the oxides formed during the spraying process, so that the amount and location of oxides in the coating was the most important characteristic in their fracture behavior. Then, the crack progression continued through the interface or, in some cases, it continued through the substrate. To locate the oxides in the coatings, nanoindentation tests have been carried out.