Performance of Ni-Al2O3 based composite coatings was evaluated under slurry erosion condition. Erosion resistance was correlated with different properties of the coatings. It was observed that fracture toughness is an important parameter that controls the erosion resistance of coatings. Content of alumina was found to have significant influence on the erosion performance and material removal mechanism of the coatings. Erosion rates were predicted using fracture-contact model. The results were observed to lie in close proximity to the experimental results. Cracking and spalling of coating, fracture of reinforcing phase and removal of splats were observed to be the primary erosion mechanisms. © 2013 Elsevier Ltd.