A ZrO2\u2014Al2O3 composite ceramic material having excellent wear resistance, hardness, strength and toughness is provided. A convex surface on each of the poles is formed as a surface in which a midpoint of the convex surface has a radial distance from the rotation axis that is greater than a radial distance of the circumferential edges of the convex surface from the rotation axis. of electroless plating and the fact that the method is performed in an anhydrous environment.