Tailoring microstructural features of Cr₃C₂-25NiCr coatings through diverse spray variants and understanding the high-temperature erosion behavior

Thermal sprayed Cr₃C₂-NiCr coatings are widely used to protect industrial components from ambient or elevated erosive degradation. Various thermal spraying techniques such as plasma spray, detonation spray (DS), high velocity oxy-fuel (HVOF) and high velocity air-fuel spray (HVAF) are widely used to deposit Cr₃C₂-NiCr coatings. The choice of thermal spraying technique governs the inflight particle velocity and temperature, resulting in unique coating microstructural features, characteristics and erosion performance. In this study, Cr₃C₂-NiCr coatings are deposited through HVAF, DS and axial plasma spray. A comprehensive comparative analysis was performed to understand the process-structure-property relationship of Cr₃C₂-NiCr coatings, which correlated with the room and high temperature erosion performance. HVAF spray deposited Cr₃C₂-NiCr coatings with preferred microstructural features and properties, ensuring superior (high/room temperature) erosive resistance. Cr₃C₂-NiCr coatings deposited via DS spray performed second best, while plasma sprayed exhibited defective microstructure with inferior mechanical properties, resulting in substandard erosion performance.