A method for making a housing of an electronic device includes applying a layer of ceramic powder material to an outer surface of a metal substrate. The layer of ceramic powder material and a top layer of the metal substrate are melted by laser irradiation, forming a ceramic-metal composite coating integrally bonding with the metal substrate when cooled. The substrate with the ceramic-metal composite coating is heated to a peak temperature, maintained at the peak temperature for a desired period of time, and then cooled down to room temperature. The heat treated metal substrate with the ceramic-metal composite coating is then formed into a desired shape.