Patent ID: 8517339

Claim:
An interference fit assembly comprising: a first metal part; and a second metal part, wherein the first metal part has a recess with an inner contact surface, and the second metal part has an outer contact surface being coupled to the inner contact surface by an interference fit, wherein at least one of the contact surfaces has: a surface layer comprising a diamond-like carbon layer; a first subsurface layer comprising a tungsten carbide carbon layer between the diamond-like carbon surface layer and the respective metal part; and a second subsurface layer comprising a chromium layer in direct contact with the respective metal part, such that the tungsten carbide carbon layer is arranged between the chromium layer and the diamond-like carbon surface layer; wherein a thickness of the chromium layer extends from a third surface in contact with the metal part to a fourth surface in contact with the tungsten carbide carbon layer, and wherein the chromium layer has a constant composition across the thickness of the chromium layer; and wherein a thickness of the tungsten carbide carbon layer extends from a first surface in contact with the chromium layer to a second surface in contact with the diamond-like carbon surface layer, and wherein the tungsten carbide carbon layer has a constant composition across the thickness of the tungsten carbide carbon layer, wherein the constant composition across the thickness of the tungsten carbide carbon layer is different than the constant composition across the thickness of the chromium layer.