Low friction wear film and method for producing the same

A method for producing a low friction wear film, the low friction wear film including:

• a chromium layer that is provided on a surface of a metal substrate;
• a tungsten carbide layer that is provided on a surface of the chromium layer, the tungsten carbide layer including a chromium-tungsten carbide gradient layer and a tungsten carbide uniform layer, the chromium-tungsten carbide gradient layer containing chromium and tungsten carbide and having a gradient composition in which a composition ratio of the chromium decreases and a composition ratio of the tungsten carbide increases as a distance from the chromium layer in a thickness direction increases, the tungsten carbide uniform layer being made of tungsten carbide provided on a surface of the chromium-tungsten carbide gradient layer;
• and a diamond-like carbon layer as a top layer that provided on a surface of the tungsten carbide layer, the method comprising:
• as a chromium layer deposition step, depositing the chromium layer by causing inert gas ions to collide with a chromium target made of chromium placed in a vacuum chamber to cause chromium atoms sputtered from the chromium target to adhere to the surface of the metal substrate;
• as a chromium-tungsten carbide gradient layer deposition step, depositing the chromium-tungsten carbide gradient layer by causing inert gas ions to collide with the chromium target and a tungsten carbide target made of tungsten carbide placed in the vacuum chamber to cause chromium atoms sputtered from the chromium target and tungsten carbide component sputtered from the tungsten carbide target to adhere to the surface of the chromium layer;
• as a tungsten carbide uniform layer deposition step, depositing the tungsten carbide uniform layer by causing inert gas ions to collide with the tungsten carbide target placed in the vacuum chamber to cause the tungsten carbide component sputtered from the tungsten carbide target to adhere to the surface of the chromium-tungsten carbide gradient layer;
• as a hydrocarbon ionization step, introducing a hydrocarbon gas into the vacuum chamber and ionizing the introduced hydrocarbon gas;
• and
• depositing the diamond-like carbon layer by causing hydrocarbon ionized in the hydrocarbon ionization step to adhere to the surface of the tungsten carbide uniform layer,
• wherein the hydrocarbon ionization step is started before the tungsten carbide uniform layer deposition step is carried out.