Effect of Detonation Spraying Parameters on the Microstructure and Properties of NiCrAlY Coatings

NiCrAlY coatings hold broad application prospects in the aero-engine field owing to their excellent densification and microhardness. To address the lack of systematic research on process parameters for preparing NiCrAlY coatings via detonation spraying, this study adopted the uniform design method to investigate the effects of four key parameters (powder feeding angle, loading distance, control timing, and spraying distance) on the coating’s microstructure, porosity, and microhardness. Quadratic polynomial regression analysis was employed to optimize the process parameters. Results indicate that the coatings exhibit no obvious delamination, with an overall average porosity of 4.93% and an optimal porosity below 1%; microhardness is predominantly determined by the loading distance (dominant factor), followed by control timing and spraying distance, while the powder feeding angle has a negligible effect; the regression model has excellent fitting performance, with a coefficient of determination of 0.988; a microhardness exceeding 700 HV_0.2 is achieved within the parameter ranges of 75-100 mm spraying distance, 345.5-465.5 mm loading distance, and 10-15 Hz control timing.