High-temperature erosion significantly reduces the durability and performance of industrial processing components. In this study, a composite coating consisting of 60 wt% nickel-based alloy (NiCrSiB) and 40 wt% alumina (Al2O3) was developed on AISI 304 stainless steel substrates using the High-Velocity Oxy-Fuel (HVOF) thermal spray method to enhance erosion resistance at elevated temperatures. The Taguchi experimental design was employed to optimize the coating process. Optical microscopy and scanning electron microscopy were used to systematically analyze the microstructure, coating thickness, and adhesion. The erosion resistance of both the optimal and standard coated samples was evaluated and compared with uncoated substrates. The results indicated that the wear resistance improved by 60% compared to the uncoated specimens, and by 70% when the procedure was optimized. Overall, the study suggests that NiCrSiB-Al2O3 composite coatings on AISI 304 stainless steel are a viable alternative for components subjected to severe erosive and high-temperature conditions.