A glass ball has a density of 2.3 to 3.2 g/cm.sup.3, a Young's modulus of 60 to 150 GPa, and an average coefficient of thermal expansion at 50 to 350 C. being 4010.sup.7 to 12010.sup.7/ C. The glass ball is formed of a glass material including, as represented by mole percentage based on oxides, 30 to 75 mol % of SiO.sub.2, 2 to 30 mol % of Al.sub.2O.sub.3, and 5 to 25 mol % of R.sub.2O, where R is at least one kind selected from Li, Na and K. The glass ball includes a compressive stress layer in a surface thereof.

A sliding member includes a bearing alloy layer, a solid lubricant layer, particles and a covering portion. The solid lubricant layer is provided on a sliding surface side of the bearing alloy layer and is deposited on the bearing alloy layer. The particles form the solid lubricant layer and are made of metal sulfide. The covering portion is provided over outermost surfaces of the particles on the sliding surface side and are made of metal oxide including the same metal element as a metal element constituting the particles.

A sliding member includes a metallic substrate, a porous layer formed on a surface of the metallic substrate, and a sliding layer that covers the porous layer. The porous layer is made of a metal itself or an alloy composition. The sliding layer is made of a lead-free resin composition. The resin composition contains an essential additive, optionally an optional additive, and a fluororesin. The essential additive is any one of a combination of a zinc compound and a carbon fiber, a combination of a zinc compound and an iron oxide, and a combination of a zinc compound, a carbon fiber and an iron oxide. A total content of the essential additive and the optional additive is 10 vol % or more and 35 vol % or less in the resin composition.

A sliding component may include an overlay comprising a polymeric material and a metal oxide. The metal oxide may have a thermal conductivity of greater than about 1.5 Wm.sup.1K.sup.1, and a Mohs hardness of between about 5 and about 7. The sliding component may be a sliding component for an engine, such as a bearing, a bearing shell, a bush, a thrust washer, a journal bearing or the like.

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.

A sliding element for an engine may include a polymer-based overlay layer disposed on a metallic substrate. The polymer-based overlay layer may include a polymer-based matrix and a metal particulate. The metal particulate may be a surface treated metal particulate.

A compressor including a housing, a shaft configured to be rotated relative to the housing to compress a refrigerant, a motor configured to drive the shaft, a lubrication system configured to supply lubricant to the compressor, and a bearing configured to support the shaft. The shaft includes a wear-resistant sleeve-like treatment on at least a portion of an outer surface of the shaft adjacent the bearing. The lubricant is a lubricant blend composition that includes two or more lubricants, the two or more lubricants including a first lubricant and a second lubricant. The first lubricant is present at a higher volume percentage than the second lubricant, and the first lubricant includes a higher viscosity than the second lubricant.

A sliding element with one substrate and at least one layer of a sliding layer material applied to the substrate is described. The sliding layer material can consist of a sliding coating with at least one cross-linkable bonding agent or at least one high-melting thermoplastic material or which consists of a material with a matrix of at least one high-melting thermoplastic material or at least one duroplastic material. This sliding layer material contains Fe.sub.2O.sub.3 with a preferred proportion 0.1 to 15% by volume.

Dynamic pressure bearing (10), including: a green compact (10), as a base material, of raw material powder including metal powder capable of forming an oxide coating; and dynamic pressure generating portions (A1 and A2) formed through die molding on an inner peripheral surface (8a) forming a radial bearing gap with an outer peripheral surface (2a1) of a shaft to be supported, that is, a shaft member (2). An oxide coating (11) is formed between particles of the metal powder by subjecting the green compact (10) to steam treatment, and the dynamic pressure bearing (10) has a radial crushing strength of 150 MPa or more.

A sliding element which has a main body and a layer system which is applied thereto. The layer system has at least a first layer of the thickness s.sub.1, which is applied to the main body, and hard material particles having a mean extent d, which are introduced into the first layer and are therefore at least fixed on the main body. The thickness s.sub.1 of the first layer is such that it amounts to at least 60% and at most 90% of the mean extent d of the hard material particles, and the hard material particles form a surface structuring of the sliding element.