Improving wear and corrosion performance of AISI 316L stainless steel substrate in liquid zinc by MoB/CoCr and MoB/CoTi gas tungsten arc clad composite coatings

Two MoB/CoCr and MoB/CoTi composite coatings were deposited on 316L stainless steel substrate by gas tungsten arc welding process. Average thickness of both coatings was same and equal to 2 mm, and they established strong bond with substrate. The microstructure and chemical composition of coatings and substrate were investigated by optical microscopy and scanning electron microscopy. X-ray diffraction analysis also was used for phase detection in coatings. Comparing coated and base metal, it was found that the presence of borides and metal compounds in coatings resulted in higher microhardness. It was found that wear and corrosion resistance of the substrate can be improved by cladding composite coatings. The wear tests showed that coatings by far outperform the substrate, and it was proved by concluded data from worn-out appearance and wear loss weight from pin on disk tests at three different loads. Wear mechanisms of the coated and non-coated samples were explored at room temperature and high temperature. Corrosion assessment in molten zinc at 480 °C for 120, 240, 360, 720, and 840 h revealed that MoB/CoCr shows better resistance toward zinc diffusion due to its non-wettability.