Plasma processing of Fe-P/rGO powder for making robust wear resistance and anticorrosion coating over mild steel

Phosphating is a widely used metal pre-treatment process due to its ability to improvise pitting corrosion resistance, wear-resistance, and adherence properties. In the present investigation, we report the manufacturing of spray grade powder of Fe-P metal ingot by mechanical hammering, milling and sieving process. The Fe-P powder and its blending with reduced graphene oxide (rGO) (2 and 4 vol%) were successfully coated over mild steel by the thermal plasma spray method for the first time. Successful retention of rGO was observed even after thermal plasma spraying of Fe-P/rGO (2 vol% and 4 vol%), which was challenging and yet to be reported. The morphological investigation of the top-coat layer and cross-section was analysed using a field emission scanning electron microscope (FESEM). The presence of G, D and 2D bands at 1580 cm(-1), 1350 cm(-1), and 2700 cm(-1,) respectively in the Raman spectra were the straightforward demonstration of the retention of rGO. Hardness and air-jet erosion tests were performed to evaluate mechanical properties in view of exploring commercial applications of such coatings. We found that Fe-P-rGO composite coatings exhibited improved hardness, erosion, and corrosion resistance properties with increasing reduced graphene oxide content.