Microstructure and mechanical characterization of NiCrBSi alloy and NiCrBSi-WC composite coatings produced by flame spraying

Abstract

In this work, an experimental study is conducted on the microstructure and mechanical properties of NiCrBSi and NiCrBSi reinforced with WC coatings, produced onto mild steel substrate by flame spraying technique. The resulting layers were analyzed using optical microscopy, scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis. Roughness measurements were made using a roughness measuring system. Microhardness tests were carried out using a microdurometer operating with Vickers indenter and the load being 3N. The results show that the microstructure contain some inhomogeneities such us pores, microcracks for the composite coating and oxides. The XRD analysis reveal that the phases present within the coatings are different from the initial powders. In addition, the presence of WC hard particles makes the hardness of the composite coating much higher than the metal alloy.