Nickel phosphorus and nickel-phosphorus-alumina coatings have been electrodeposited. X-ray diffraction studies show that both types of coating become more crystalline with the formation of Ni 3 P and Ni upon heat treatment. The hardness of the as-plated and heat-treated coatings suggested that the as-deposited coatings containing alumina would be more wear-resistant than those containing only nickel and phosphorus, but with the reverse being true for the same deposits following heat treatment. The phosphorus content of deposits obtained by electrodeposition can be controlled by varying the phosphorous acid in the bath.