The corrosion behavior of hard W–C system chemical vapor deposition layers in HCl and H2S aqueous solutions

Abstract

The results of a study of anticorrosion performance of low carbon containing tungsten-based hard chemical vapor deposition (CVD) coatings with microhardness from 5 to 17 GPa are presented in this work. Their high corrosion resistance in hydrochloric acid and hydrogen sulfide solutions is noted, as their corrosion rate does not exceed 6 μm per year in hydrochloric acid solution and 15 μm per year in hydrochloric acid solution saturated with hydrogen. The open circuit potentials correspond to tungsten (VI) oxide formation so the corrosion process supposedly runs in passive state. Taking into account the low porosity of the CVD layers, which is lower than 0.02%, these coatings are promising for application as anticorrosion wear-resistant coatings for chemical and oil and gas apparatus responsible units.