Patent ID: 9617654
Date: 2017-04-11
CPC Classifications: C23C,C25F,E21B,Y10T

Claim:
1. A multi-layer low friction coating comprising: i) an under layer comprising CrN, wherein the under layer ranges in thickness from 5 to 15 μm, ii) an optional adhesion promoting layer comprising CrC, wherein the adhesion promoting layer ranges in thickness from 5 to 15 μm and is contiguous with a surface of the under layer, and iii) a functional layer comprising diamond-like-carbon (DLC), wherein the functional layer ranges from 5 to 15 μm and is contiguous with a surface of the optional adhesion promoting layer or a surface of the under layer, and wherein the diamond-like-carbon (DLC) is selected from the group consisting of ta-C, DLCH, and combinations thereof, wherein the optional adhesion promoting layer is interposed between the under layer and the functional layer, wherein the coefficient of friction of the functional layer of the low friction coating as measured by the block on ring friction test is less than or equal to 0.15, and wherein the abrasion resistance of the low friction coating as measured by the modified ASTM G105 abrasion test yields a wear scar depth of less than or equal to 20 μm and a weight loss less than or equal to 0.02 grams.