Sliding element for internal combustion engines

A method for coating a sliding element for an internal combustion engine, the method comprising:

• applying a bonding layer on an annular external surface of a base material;
• forming a sliding layer on the bonding layer via physical vapor deposition by cathodic arc;
• wherein the sliding layer is composed of hard amorphous carbon of a combined matrix of sp3/sp2 bonds;
• wherein forming the sliding layer includes incorporating a plurality of nanoparticles of graphite within the combined matrix of sp3/sp2 bonds;
• and
• wherein forming the sliding layer further includes forming a first depth region, a second depth region, and a third depth region disposed sequentially one after the other, the first depth region including a prominence of sp3 bonds, the second depth region including a prominence of sp2 bonds, and the third depth region including a prominence of sp3 bonds.

An internal combustion engine, comprising at least one sliding element including a base material having an annular external surface upon which a bonding layer and a sliding layer are sequentially deposited, the sliding layer composed of hard amorphous carbon of a combined matrix of sp3/sp2 bonds, wherein:

• the sliding layer includes a plurality of nanoparticles of graphite incorporated within the combined matrix of sp3/sp2 bonds;
• the sliding layer is substantially free of hydrogen;
• the sliding layer includes a first depth region, a second depth region, and a third depth region disposed sequentially one after the other;
• the first depth region includes a prominence of sp3 bonds;
• the second depth region includes a prominence of sp2 bonds;
• and
• the third depth region includes a prominence of sp3 bonds.