Piston ring and its production method
AssigneeRiken
InventorsMasayuki SATO, Yuuichi MURAYAMA, Youhei IWAMOTO, Takuma SEKIYA
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Abstract
To provide a hard-amorphous-carbon-coated piston ring having low friction and excellent wear resistance and peeling resistance to reduce the fuel consumption of automobiles, an outer peripheral surface of a steel-made piston ring base material is provided with a primary layer constituted by a CrN/Cr laminate coating or a CrN/TiN laminate coating as thick as 10-60 μm, which is obtained by alternately laminating CrN-type chromium nitride and chromium metal or TiN-type titanium nitride, an intermediate layer of chromium metal and/or titanium metal as thick as 0.05-1.0 μm, and then a hard amorphous carbon coating as thick as 0.4-20 μm.
Claims8
A piston ring having a hard amorphous carbon coating having a thickness of 0.4-20 μm at least on its outer peripheral sliding surface;
- the base material of said piston ring being steel;
- a primary layer and an intermediate layer being interposed between said base material and said hard amorphous carbon coating;
- said primary layer comprising a CrN/Cr or CrN/TiN laminate coating as thick as 10-60 μm, which is an alternate laminate of CrN-type chromium nitride and chromium metal or TiN-type titanium nitride;
- and
- said intermediate layer comprising chromium metal and/or titanium metal as thick as 0.05-1.0μm.
A method for producing a piston ring having a hard amorphous carbon coating having a thickness of 0.4-20 μm at least on its outer peripheral sliding surface, comprising the steps of
- adjusting the surface roughness RzJIS of a base material of said steel-made piston ring to 0.05-3 μm;
- alternately laminating CrN-type chromium nitride and chromium metal or TiN-type titanium nitride to form a CrN/Cr laminate coating or a CrN/TiN laminate coating as thick as 15-70 μm;
- grinding said CrN/Cr laminate coating or said CrN/TiN laminate coating;
- and
- forming an intermediate metal layer and the hard amorphous carbon coating thereon.
Dependencies are inferred from the claim text.