Abstract: An alpha-alumina coated turbocharger turbine wheel includes a hub portion, a plurality of blades disposed about the hub portion, each blade of the plurality of blades having a leading edge and a trailing edge, a centerline passing axially through the hub portion, and a back-side wall defined radially between the leading edge of each blade of the plurality of blades and the centerline. The turbocharger turbine wheel is made of a metal alloy and a surface coating layer of alpha-alumina. The surface coating layer of alpha-alumina may be disposed only on the hub portion, the plurality of blades, and a radially-outer portion of the back-side wall. The radially-outer portion is defined between a radial distance from the centerline and the leading edge of each blade of the plurality of blades. Alternatively, the surface coating layer of alpha-alumina may be disposed on the hub portion, the plurality of blades, and an entirety of the back-side wall.

Abstract: A method for fabricating a vane for a variable geometry turbocharger (VGT) includes the steps of providing or obtaining a substrate metal in powdered form, mixing a binder with the powdered substrate metal to form a mixture, performing an injection molding process using the mixture to form a green substrate in the shape of the vane, debinding the green substrate to form a brown substrate in the shape of the vane having a porous structure, applying a surface treatment slurry to at least a portion of the brown substrate, and sintering the surface treated brown substrate to form the vane.

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.

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.

Abstract: An alpha-alumina coated turbocharger turbine wheel includes a hub portion, a plurality of blades disposed about the hub portion, each blade of the plurality of blades having a leading edge and a trailing edge, a centerline passing axially through the hub portion, and a back-side wall defined radially between the leading edge of each blade of the plurality of blades and the centerline. The turbocharger turbine wheel is made of a metal alloy and a surface coating layer of alpha-alumina. The surface coating layer of alpha-alumina may be disposed only on the hub portion, the plurality of blades, and a radially-outer portion of the back-side wall. The radially-outer portion is defined between a radial distance from the centerline and the leading edge of each blade of the plurality of blades. Alternatively, the surface coating layer of alpha-alumina may be disposed on the hub portion, the plurality of blades, and an entirety of the back-side wall.

Abstract: A method for fabricating a vane for a variable geometry turbocharger (VGT) includes the steps of providing or obtaining a substrate metal in powdered form, mixing a binder with the powdered substrate metal to form a mixture, performing an injection molding process using the mixture to form a green substrate in the shape of the vane, debinding the green substrate to form a brown substrate in the shape of the vane having a porous structure, applying a surface treatment slurry to at least a portion of the brown substrate, and sintering the surface treated brown substrate to form the vane.