The components of hydropower plants are susceptible to sediment erosion caused by hard particles in the water. These hard particles cause substantial material loss and a reduction in the performance of the hydraulic turbines. The present study deals with the mitigation of sediment erosion in hydraulic turbines by developing a protective coating (CoNiCrAlY-Al2O3 metal-ceramic composite) using a high-velocity oxygen-fuel (HVOF) coating technique. Hardness measurement, surface wettability analysis, and surface roughness measurement were conducted to characterize the coatings, whereas scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS) were performed for metallurgical characterization. The slurry/sediment erosion behavior of bare and coated substrate was investigated using a slurry erosion tester. Experiments were performed for five coating compositions at different impact angles (30° ≤ ϴ ≤ 90°) and velocities (6 ≤ v ≤ 12 m/s). The maximum improvement in erosion performance (reduction in erosion rate compared to bare substrate ≈ 28.12 % at 30°, 9.29 % at 45°, and 11.69 % at 90° impact angle) was obtained for the coating having 12 wt% alumina doped into Co-NiCrAlY. The coating's performance was improved due to increased hardness, high shielding effect, and reduction in impact energy on Al2O3 by using CoNiCrAlY-Al2O3 deposition. The empirical correlation between erosion rate and velocity for both bare and coated substrates has also been proposed.