Corrosion behavior of WC–Co coating by plasma transferred arc on EH40 steel in low-temperature

Abstract To investigate the corrosion behavior of WC–Co composite coating, plasma transferred arc (PTA) welding was applied to prepare coating on hull steel EH40 for achieving good metallurgical bonding. The phases coatings were mainly composed WC particles, solid solution γ-Co, Fe 3 Ni 2 , SiO and Mo C. After electrochemical test, it can be concluded that Co-based with 45% content has better resistance in low temperature marine environment obtaining denser oxide film. Through X-ray photo electron spectroscopy (XPS) analysis, main products immersion Co(OH) Co O 4 . These aggregate form a stable product film, which plays some protective role coating. Hard particle is also partially oxidized WO pitting hole 60% most serious. Pitting easy occur at interface defects.