PURPOSE: To obtain the title parts being hard and having a lustrous, black tone by forming three layers of which the first layer is formed of titanium and the second layer, titanium nitride or carbide and the top layer, SiAlON.

CONSTITUTION: The first layer of the title parts is formed of titanium, and an affinity for a basic material such as a metal, a plastics or a ceramics is heightened. The second layer thereof is formed of titanium nitride, titanium carbide or carbonitride and is made a hard layer with the hardness of Hv1000 or above. The top layer thereof is formed of SiAlON, and the top layer with an externally black tone is obtained and is extremely heightened up to the hardness of Hv1500 or above. By such a formation, the title parts with high durability and with a lustrous, black tone can be obtained.