An Analytical Perspective on HVOF Thermal Spray Coatings of Chromium-Nickel Alloys on T31 Steel for Enhanced Surface Performance

The application of chromium-nickel (75:25) coatings on T31 alloy steel, a material frequently used in engineering components exposed to demanding service conditions, using the High Velocity Oxy-Fuel (HVOF) thermal spray technique is examined in this review. By impacting molten particles at high velocities, the HVOF method makes it possible to build dense, low-porosity coatings with exceptional adherence. The paper explores the basics of the HVOF spraying method, important process variables, and the justification for choosing the Cr-Ni alloy because of its remarkable synergy, in which nickel improves toughness and thermal stability while chromium offers hardness and corrosion resistance. Along with discussing how these coatings greatly improve T31's mechanical performance, wear resistance, and corrosion protection, the paper also provides insights into the resulting coating microstructure, which is usually lamellar and compact. Various case studies and research findings are analyzed to highlight real-world performance improvements. Potential integration with additive manufacturing and environmentally sustainable coating solutions are also discussed, making this review a comprehensive reference for researchers and practitioners aiming to advance surface engineering through HVOF technology.