Abstract: A cubic boron nitride sintered material comprising cubic boron nitride grains, a binder phase, and a void, in which a percentage of the cubic boron nitride grains based on the total of the cubic boron nitride grains and the binder phase is 40 vol % to 70 vol %, a percentage of the binder phase based on the total of the cubic boron nitride grains and the binder phase is 30 vol % to 60 vol %, the binder phase includes 10 vol % to 100 vol % of aluminum oxide grains, an average grain size of the aluminum oxide grains is 50 to 250 nm, the cubic boron nitride sintered material comprises 0.001 vol % to 0.100 vol % of one or more first voids, and at least one portion of each of the first voids is in contact with the aluminum oxide grains.

Abstract: A lubricant and combination lubricant and refrigerant composition for use in a refrigerating machine in which a substitute freon refrigerant, which lubricant contains a polymer of a fumaric ester or a fumaric ester and a copolymerizable alkylene, and optionally contains an organic carboxylic ester or a polyalkylene glycol with a kinematic viscosity of 2 to 30 cSt. The lubricant is compatible with substitute freon refrigerants such as hydrogen-containing halogenated hydrocarbons, particularly R 134a, in a wide temperature range, has a high viscosity index, is thermally and chemically stable, and has an excellent lubricity.

Abstract: A fluid composition for use in fluid couplings has the superior anti-gelling properties of an organopolysiloxane base oil, is low in changes in viscosity and changes in torque, is stable and has extremely high durability, and is especially useful because of its viscosity as a fluid for "fan" couplings. The fluid composition according to the invention is provided, by adding at least one type of ferrocene derivative, in a weight ratio wherein the atomic iron content is 10 ppm to 5,000 ppm, selected from the group consisting of the compounds represented by the general formula (1) and the general formula (2) for an organopolysiloxane base oil having a viscosity of 50 mm.sup.2 /s to 20,000 mm.sup.2 /s at 25.degree. C. The compounds of general formula (1) may be represented by the following formula: ##STR1## wherein R.sub.1 and R.sub.2 are identical or different, and are each independently selected from the group consisting of C.sub.2-25 alkyl, alkenyl, cyclo-alkyl, and cyclo-alkenyl. Additionally, one of R.sub.

Abstract: The invention provides a fluid composition for a fluid coupling, which is excellent in viscosity stability and torque stability, and comprises a polyorganosiloxane base oil having a viscosity of 3,000-500,000 mm.sup.2 /sec at 25.degree. C. and at least one 5-membered heterocyclic compound incorporated in a proportion of 0.01-3.0 wt. % based on the total weight of the composition, said 5-membered heterocyclic compound being selected from the group consisting of thiadiazole derivatives and thiazole derivatives, both, having at least one monovalent group represented by the formula --S.sub.x --R.sup.6 in which R.sup.6 is a saturated or unsaturated monovalent group or atom composed of at least one atom selected from a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom and a sulfur atom, and x is a number of 1 or greater.

Abstract: The invention concerns a lubricating oil composition in which a lubricating oil base contains 0.1% by weight to 20% by weight of an aromatic glycidyl carboxylate having the following general formula (1): ##STR1## wherein R is a C.sub.6-14 aryl or alkylaryl group, and n represents an integer of 1 or 2, and/or 0.05% by weight to 10% by weight of a phosphonate type additive having the following general formula (2): ##STR2## where R.sub.1 or R.sub.2 is selected from the group consisting of alkyl, aralkyl, aryl and hydroxyalkyl groups that may or may not have a substitute, and two R.sub.2 groups may be identical with or different from each other, and which is excellent in stability to hydrolysis, heat and oxidation as well as in lubricating properties, and so provides a particularly excellent refrigerating oil composition.

Abstract: The invention concerns a lubricating oil composition in which a lubricating oil base contains 0.1% by weight to 20% by weight of an aromatic glycidyl carboxylate having the following general formula (1): ##STR1## wherein R is a C.sub.6-14 aryl or alkylaryl group, and n represents an integer of 1 or 2, and/or 0.05% by weight to 10% by weight of a phosphonate type additive having the following general formula (2): ##STR2## where R.sub.1 or R.sub.2 is selected from the group consisting of alkyl, aralkyl, aryl and hydroxyalkyl groups that may or may not have a substitute, and two R.sub.2 groups may be identical with or different from each other, and which is excellent in stability to hydrolysis, heat and oxidation as well as in lubricating properties, and so provides a particularly excellent refrigerating oil composition.