Characteristics of Thermally Sprayed NiCrBSi Coatings before and after Electromagnetic Induction Remelting Process

Active mechanical components that work in highly aggressive environments require protection against premature deterioration and, at the same time, it is necessary to ensure a long lifespan. In order to achieve these important features, a protective coating can be added. In this work, a NiCrBSi self-fluxing alloy powder was employed, as feedstock material. The coating was deposited by means of oxyacetylene flame spraying process, achieving a thickness of approximately 1000 mu m and exhibiting a high degree of porosity and a weak mechanical adhesion to the substrate. To improve these characteristics, a remelting process using high frequency currents was applied. After the remelting process, the porosity decreased, from an initial value of approximately 15%, to a final value under 3%. Although the microhardness values did not change significantly, both wear-rate and corrosion behavior improvement, after the electromagnetic remelting, was observed.