Wear and Corrosion Behaviour of Ni-WC Coatings in Sulfuretted Hydrogen Medium

To improve the abrasion and corrosion resistance of deep-sea oil drilling tools, in this study, Ni-based coating containing different content of WC particles were coated on the stainless steel by plasma transferred arc (PTA). The abrasion and corrosion behaviors of the coating were studied in the saturated sulfuretted hydrogen medium. The morphology and composition of the coating were characterized by X-ray diffraction, scanning electron microscopy with an energy dispersive spectrometer, X-ray photoelectron spectroscopy. Micro-hardness test, friction and wear test were taken to value the hardness and wear resistance. Corrosion resistance and pitting distribution of the coating were studied by the potentiodynamic polarization and 3D optical profilometer. Results show that the Ni-WC coating, which is prepared by PTA process, is consisted of WC, W2C, Ni and Ni3Fe. However, the volume fraction of WC has a great influence on the abrasion and corrosion resistance of the coating. When the volume fraction of WC is 60%, Ni-60% WC coating exhibites higher wear and corrosion resistance in H2S medium compared with the other groups (Ni alloy coating and Ni- 30% WC). Therefore, it introduces a new perspective and an option for abrasion and corrosion control in deep-sea oil drilling environment.