A method including substituting an atmosphere in a space, in which a sliding surface formed of a metal or a ceramic material, and a slid surface are disposed, with a gas atmosphere containing a hydroxyl group-containing compound and at least one of hydrogen and nitrogen, and relatively sliding the sliding surface against the slid surface by a Hertzian contact stress of 1.0 GPa or more in the space under the gas atmosphere containing the hydroxyl group-containing compound at least one of hydrogen and nitrogen. As a result, it is possible to form, on the sliding surface, a low-friction coating that stably exhibits a significantly low friction coefficient, for example, of 10.sup.4 order (less than 0.001).

A low-friction coating includes: an aliphatic hydrocarbon group showing a peak in a region of 2,900 cm.sup.1 to 3000 cm.sup.1 in an infrared absorption spectrum; a carbonyl group showing a peak in a region of 1,650 cm.sup.1 to 1,800 cm.sup.1 in an infrared absorption spectrum; an aromatic component (C.sub.7H.sub.7.sup.+) showing a peak at mass 91.1 in a positive ion spectrum obtained by TOF-SIMS; and a condensed ring based component (C.sub.9H.sub.7.sup.+) showing a peak at mass 115.2 in the positive ion spectrum obtained by TOF-SIMS.

A low-friction coating includes: an aliphatic hydrocarbon group showing a peak in a region of 2,900 cm.sup.1 to 3000 cm.sup.1 in an infrared absorption spectrum; a carbonyl group showing a peak in a region of 1,650 cm.sup.1 to 1,800 cm.sup.1 in an infrared absorption spectrum; an aromatic component (C.sub.7H.sub.7.sup.+) showing a peak at mass 91.1 in a positive ion spectrum obtained by TOF-SIMS; and a condensed ring based component (C.sub.9H.sub.7.sup.+) showing a peak at mass 115.2 in the positive ion spectrum obtained by TOF-SIMS.

A top of rail (TOR) applicator has a bar positioned in a housing and an exit orifice on the upper portion of the bar for delivering a friction control composition to the crown of a railhead. The upper portion of the bar slopes away from the friction control composition exit orifices. The bar may be composed of an elastomer such as polyurethane. Passageway extend from an inlet or entry orifice to the exit orifices. The friction reduction composition is pumped into the entry orifice, through the passageways to the exit orifices and then onto the crown of the railhead. The friction reduction composition may be thixotropic.

A water based dispersion that includes lubricating nanoparticles. The lubricating nanoparticles can be provided by at least one intercalation nanoparticle of a metal chalcogenide in dispersion with the water base. The at least one intercalation nanoparticle may have a geometry that is fullerene-like, tubular-like structure or be substantially spherical or the intercalation nanoparticles may include particles have each of the aforementioned geometries. The intercalation nanoparticle is surface treated with a dispersant that is water soluble and includes a polar functional group.

A top of rail (TOR) applicator has a bar positioned in a housing and an exit orifice on the upper portion of the bar for delivering a friction control composition to the crown of a railhead. The upper portion of the bar slopes away from the friction control composition exit orifice. The bar may be composed of an elastomer such as polyurethane. A passageway may extend from an inlet port to the exit orifice. The friction reduction composition is pumped into the inlet port, through the passageway to the exit orifice and then onto the crown of the railhead. The friction reduction composition may be thixotropic.

A lubricating composition comprising a base oil of lubricating viscosity and one or more lubricant additives, wherein the base oil comprises or consists of a base stock which comprises or consists of at least one isoprenoid compound comprising: (i) one or two oxygen-containing moieties independently selected from ether and ester moieties; (ii) a first acyclic isoprenoid moiety containing 1 to 5 isoprenyl units; and (iii) optionally, a second acyclic isoprenoid moiety containing 1 to 5 isoprenyl units with the proviso that at least one isoprenoid moiety contains 3 to 5 isoprenyl units where the isoprenoid compound contains a single ether moiety.

A lubricating composition comprising a base oil of lubricating viscosity and one or more lubricant additives, wherein the base oil comprises or consists of a base stock which comprises or consists of at least one isoprenoid compound comprising: (i) one or two oxygen-containing moieties independently selected from ether and ester moieties; (ii) a first acyclic isoprenoid moiety containing 1 to 5 isoprenyl units; and (iii) optionally, a second acyclic isoprenoid moiety containing 1 to 5 isoprenyl units with the proviso that at least one isoprenoid moiety contains 3 to 5 isoprenyl units where the isoprenoid compound contains a single ether moiety.

The refrigerator oil of the present invention contains an oxygen-containing base oil and a viscosity index improver, and has a viscosity index (VI) of 200 or more and a volume resistivity of 110.sup.9 m or more.

A grease composition which is excellent in seizure resistance can be provided without deteriorating resistance to stirring in the rolling device, and a rolling device in which the grease composition intervenes to a predetermined portion can be also provided by use of a grease composition comprising a base oil and a thickener, the thickener being a diurea compound obtained by allowing an amine mixture comprising alkylphenylamine, an alkyl group of which has 8 to 16 carbon atoms, and cyclohexylamine, to react with a diisocyanate compound, the amount of cyclohexylamine in the amine mixture being 80% by mole or more and less than 91% by mole, and a worked penetration being 300 to 330.