The Role of Nitrogen Doping in Enhancing the Thermal Stability and Wear Resistance of AlSi Coatings at Elevated Temperatures

AlSi and nitrogen-doped AlSi (AlSiN) coatings were deposited onto 22MB5 steel, while h-BN coatings were applied to H13 steel using the magnetron-sputtering method. The thermal stability and tribological properties of the AlSi and AlSiN coatings were systematically investigated from room temperature to 800 °C in ambient air. The results indicate that the AlSiN coatings with an FeAl transition layer exhibited outstanding wear resistance and high thermal stability behaviors at elevated temperature because the FeAl layer can inhibit the diffusion of Al and absorb Fe, forming iron-rich intermetallic compounds with a high bonding strength. The FeAl layer plays a critical role in enhancing the coating’s performance. Analysis of the wear mechanisms revealed that the AlSiN coating primarily underwent adhesive wear, while the AlSi coating suffered from abrasive and oxidative wear. These findings offer valuable insights for developing protective coatings for the hot-stamping-forming process.