A method for coating a turbomachine part with a self-lubricating includes: providing a rotor or thrust disc of the turbomachine; applying, by a thermal spraying process, a self-lubricating coating having of a mixture of 50 to 90 wt % of alumina (Al.sub.2O.sub.3) with titanium oxide (TiO.sub.2) to a surface of the rotor and/or a surface; and finishing the coated surface of the rotor and/or thrust disc.

An insulated bearing includes an outer ring, an inner ring, and a plurality of rolling elements. At least one of the outer ring and an inner ring is made of metal, the plurality of rolling elements are provided between the outer ring and the inner ring, so as to be freely rolled, and at least one of the outer ring and an inner ring is coated with an insulating layer. The insulating layer is formed of a mixture in which silicon carbide and/or aluminum nitride as an additive are/is dispersed in aluminum oxide as a base matrix. The content of the additive is 1 to 40 mass % with respect to the total amount of the mixture.

A ceramic ball material according to an embodiment including: a spherical portion; and a band-shaped portion formed over a circumference of a surface of the spherical portion. The ceramic ball material has a ratio Rtb/Rts of 1.0 or more, where Rtb denotes a maximum cross-sectional height of a roughness profile on an outer peripheral surface of the band-shaped portion; and Rts denotes a maximum cross-sectional height of roughness on an outer peripheral surface of the spherical portion.

An insulated bearing includes an outer ring, an inner ring, and a plurality of rolling elements. At least one of the outer ring and an inner ring is made of metal, the plurality of rolling elements are provided between the outer ring and the inner ring, so as to be freely rolled, and at least one of the outer ring and an inner ring is coated with an insulating layer. The insulating layer is formed of a mixture in which silicon carbide and/or aluminum nitride as an additive are/is dispersed in aluminum oxide as a base matrix. The content of the additive is 1 to 40 mass % with respect to the total amount of the mixture.

A method of providing electrical discharge machining protection for a bearing is provided. The method includes (a) providing a bearing ring, (b) ionizing pure aluminum and depositing a pure aluminum layer on at least a portion of the bearing ring, (c) immersing the bearing ring in acid to convert the pure aluminum layer to an aluminum oxide layer, and (d) immersing the bearing ring in deionized water to seal the aluminum oxide layer.

A rolling-element bearing includes a first ring element, a second ring element, a plurality of rolling elements rotatably disposed between the first ring element and the second ring element, and an electrically insulating layer on a surface of the first ring element. The electrically insulating layer is a ceramic layer containing a mixture of aluminum oxide (Al.sub.2O.sub.3) and titanium oxide, and the insulating layer includes titanium compounds that contain reduced titanium oxide (TiO.sub.x) and/or metallic titanium (Ti), and the insulating layer further includes a cured synthetic resin sealer.

An insulated bearing assembly for coupling a shaft with an outer member includes an inner race disposed upon the shaft and an outer race disposed about the inner race and having an outer circumferential surface and axial ends. An annular insulator is formed of an electrically insulative and thermally conductive material and is coupled with either the outer race or the inner race such that the insulator is generally disposed between the outer race and the outer member or between the inner race and the shaft. A polymeric member has an annular portion(s) disposed against one of the two axial ends of the coupled outer race or inner race and an axial portion(s) extending from the annular portion and coupled with the insulator member so as to retain the insulator member coupled with the outer race or the inner race when the bearing assembly is separate from the outer member.

A bearing component, such as a bearing roller or a bearing ring, has an exterior surface and includes at least one interior region made of a recycled material which region is spaced from and does not form any part of the exterior surface. The recycled material and the unrecycled material may each include silicon nitride and/or sialon and/or silicon carbide and/or a ceramic material. Also a method of forming the component.

A composite ring includes a first region including a first polymeric material; a second region including a second polymeric material; and an interfacial region defining a compositional gradient between the first region and the second region; wherein a wear resistance of the first region is different from a wear resistance of the second region. A composite bearing includes a first layer including a first polymeric material and a first filler; a second layer disposed on the first layer, the second layer including a second polymeric material and a second filler; and an interfacial region defining a compositional gradient between the first layer and the second layer, wherein a wear resistance of the first layer is greater than a wear resistance of the second layer, and wherein a mechanical strength of the second layer is greater than a mechanical strength of the first layer.

A ceramic ball material according to an embodiment including: a spherical portion; and a band-shaped portion formed over a circumference of a surface of the spherical portion. The ceramic ball material has a ratio Rtb/Rts of 1.0 or more, where Rtb denotes a maximum cross-sectional height of a roughness profile on an outer peripheral surface of the band-shaped portion; and Rts denotes a maximum cross-sectional height of roughness on an outer peripheral surface of the spherical portion.