Modification of flame-sprayed NiCrBSi alloy wear-resistant coating by friction stir processing and furnace re-melting treatments

Wear-resistant coatings are critical to many industries for extending the life span of components and reducing costs. NiCrBSi coatings are one of the most utilized Ni-base wear-resistant coatings for both ambient and high temperature applications, capable of being applied by both welding and thermal spray processes. If thermal spraying is used to apply NiCrBSi coatings, a modification treatment is often needed to minimize imperfections of the coating layer and improve its properties. Here, use of friction-stir processing (FSP) and furnace re-melting (FR) processing are investigated in terms of their effect on the microstructure and wear properties of a NiCrBSi coating applied on plain carbon steel. Optical and electron microscopy, X-ray diffraction analysis, sliding wear test, and micro-hardness measurements have been used to characterize samples. Based on the results, FSP improved performance versus FR in terms of homogeneity, micro-hardness enhancement, and elimination of defects, leading to more homogeneous coating structures. Also, porosity in the coating layer drastically decreased from 14 % in the as-sprayed condition to 0 % after the FSP process. Additionally, by performing the friction-stir processing, the hardness of the coating increased by 60 % due to a reduction of defects in the layer while breaking down and homogeneously dispersing hard particles in the microstructure.

Automated summary

Wear-resistant coatings are vital in various industries for prolonging component lifespan and reducing costs. NiCrBSi coatings are widely used for wear resistance and can be applied by both welding and thermal spray processes. This study investigates the effects of friction-stir processing (FSP) and furnace re-melting (FR) on the microstructure and wear properties of a NiCrBSi coating on carbon steel.