Thermal spraying of a high nitrogen duplex austenitic-ferritic steel

Abstract High nitrogen steels have received more and more attention due to their high comprehensive properties in recent years. Thermal spraying of such steels provides alternative coatings with improved mechanical and corrosion performance compared to some of today's conventional steel coatings. In this study a high nitrogen duplex austenitic–ferritic steel was sprayed using different thermal spray processes. The influence of the process and spray parameters was investigated. An increase of the nitrogen content could be realized by plasma spraying using nitrogen as a secondary plasma gas. However, the increase of nitrogen took place non-uniformly. The HVOF coatings provided better wear and corrosion properties than the plasma spray coatings.