Turbocharger compressor wheels having a bi-layered coating and methods for manufacturing the same

Abstract

A compressor wheel for a turbocharger includes a hub portion defining a rotational axis and a plurality of blades extending radially outward from the hub portion. Each blade of the plurality of blades includes a leading edge, the leading edges of each blade of the plurality of blades forming an inducer portion of the compressor wheel. Each blade of the plurality of blades further includes a trailing edge, the trailing edges of each blade of the plurality of blades forming an exducer portion of the compressor wheel. The inducer portion is positioned longitudinally forward from the exducer portion along a rotational axis with respect to a flow of air along the compressor wheel. The hub portion and the plurality of blades include a substrate metal. The substrate metal of the hub portion and the plurality of blades has coated directly thereon a first coating layer including electroless nickel-phosphorous. The first coating layer has coated directly thereon a second coating layer including hard chrome. The second coating layer has a thickness that is greatest at the inducer portion, with the thickness of the second coating layer decreasing rearward towards the exducer portion such that the thickness of the second coating layer is about zero microns at or longitudinally forward of the trailing edges of each blade of the plurality of blades.