Erosion and corrosion behavior of shrouded plasma sprayed Cr3C2-NiCr coating.

This study attempted to investigate the effect of coating porosity on the ability to protect the substrate from corrosion and the combined action mechanism of corrosion and erosion wear. In this study, five coatings with different porosity characteristics were deposited on the substrate. The microstructures and phase composition of coatings were characterized. Furthermore, corrosion and erosion wear behavior of coatings were analyzed. The erosion wear patterns of uncorroded and corroded coatings were revealed. The mechanism that erosion wear was influenced through corrosion was determined. Results indicated that corrosion and erosion wear resistance were remarkably affected by porosity. The unsealed cermet failed to protect the substrate and aggravated the corrosion of the substrate through galvanic corrosion. Porosity affected the microcutting performance by influencing hardness, whereas corrosion affected the microcutting and deformation wear performance by acting on hardness, resulting in the loosened structure. The main erosion mechanisms of uncorroded and corroded coatings were microcutting and deformation wear, respectively. Deformation wear was induced by corrosion, and microcutting. The qualitative analysis of the combined action of corrosion and erosion can provide guidance in coating design. • Unsealed coating promoted substrate galvanic corrosion, not surface corrosion. • Revealed negative effects of porosity on erosion and corrosion resistance • Revealed erosion wear patterns of corroded and uncorroded coatings • Revealed the mechanism that erosion wear affected by corrosion [ABSTRACT FROM AUTHOR]