Modeling, deposition, and mechanical characterizations of single-step surface coating using high-speed grinding

Byproducts of metal grinding are often treated as waste, hence disposed of in the open environment as a swarf. These upshots in serious economic, health, and environmental concerns. In the present study, the swarf particles being produced by a high-speed cut of the saw were directly impacted onto the textured surface of the aluminum substrate and deposited as a hard coating. This was initiated by developing a model to ascertain the optimal parameters such as a stand-off distance, total flight time, and temperature generated thereof. Accordingly, a 1-mm-thick coating was successfully deposited adopting a cutting speed of 71 m/s, stand-off distance ∼ 700 mm, feed 50 mm/min, and depth of cut of 3 mm. Subsequently, characterizations have been carried out to analyze the characteristics such as morphology, microstructure, elemental composition, microhardness, Young’s modulus, and coating-substrate adhesion strength. Scanning electron microscopy images of the pristine coating revealed a dense structure, showing excellent cohesion among the particles and adhesion to the substrate. Metallurgical and elemental investigations using X-ray diffraction and Raman spectroscopy analyses advocated the formation of a steel-iron oxide composite, thereby portraying the coating as a steel metal matrix composite. The average microhardness of the coated aluminum substrate was found to be 331 HV, which is substantially higher compared to that of the substrate, which was recorded as 37 HV. The average Young’s modulus of the substrate and coating was recorded as ∼ 43 GPa and ∼ 77.2 GPa, respectively. Coating-substrate interface failure was found during the tensile adhesion test as per ASTM C633:2022, and an average adhesion strength of 13.71 MPa was found.