Cylinder liners with adhesive metallic layers and methods of forming the cylinder liners

A cylinder liner for receiving a piston of an internal combustion engine, comprising:

• a body formed of a metal material extending circumferentially along a center axis and longitudinally between from a first body end to a second body end;
• said body including an inner surface facing said center axis and extending longitudinally from said first body end to said second body end;
• said inner surface surrounding said center axis and presenting bore having a cylindrical shape between said first body end and said second body end;
• said inner surface having an inner length extending from said first body end to said second body end;
• said first body end presenting a first opening surrounding said center axis and having a circular shape;
• said second body end presenting a second opening surrounding said center axis and having a circular shape;
• said bore having volume capable of receiving a piston such that said piston can reciprocate within said cylinder liner and slide along said inner surface during operation of the internal combustion engine;
• said body presenting an outer surface facing opposite said inner surface and extending longitudinally from said first body end to said second body end;
• said outer surface having an outer length extending from said first body end to said second body end;
• said metal material of said body having a hardness of at least 20 HRC and a thermal conductivity of 40 to 50 W/(m·K);
• said metal material of said body consisting of steel or a steel alloy;
• a wear resistant layer disposed on said inner surface, said wear resistant layer produced by a sputtering process;
• said wear resistant layer being a diamond-like carbon (DLC) coating;
• said DLC coating including a hydrocarbon and at least one of silicon and germanium;
• said wear resistant layer extending continuously from said first body end to said second body end;
• said wear resistant layer having a thickness extending between said inner surface and said center axis;
• said thickness of said wear resistant layer varying by not more than 5% along at least 70% of said inner length;
• and
• a metallic adhesive layer disposed between said wear resistant layer and said inner surface;
• said metallic adhesive layer adhering said wear resistant layer to said inner surface;
• said metallic adhesive layer consisting essentially of metal;
• said metal of said metallic adhesive layer including at least one of chromium and titanium;
• said metallic adhesive layer having a thickness extending between said inner surface and said center axis;
• said thickness of said metallic adhesive layer varying by not more than 5% along at least 70% of said inner length;
• and
• said metallic adhesive layer being disposed on said second body end and along 1 to 40% of said outer length adjacent said second body end.