Patent ID: 8039096

Claim:
A coating comprising: a first layer of a ceramic orthorhombic boride-based alloy represented by the general formula AlMgB 14 —X and having a thickness of from greater than 1 micron to less than or equal to 3 microns; wherein X is present in an amount of from 0 to 70 parts by weight based on 100 parts by weight of said ceramic orthorhombic boride-based alloy and is a doping agent selected from the group of Group IV elements and borides and nitrides thereof; and a second layer disposed on said first layer and including amorphous carbon present in a gradient concentration that increases with a distance from said first layer; wherein the coating has a hardness of from 10 to 20 GPa; wherein the coating has a coefficient of friction of less than or equal to 0.12.