Abstract: A heat-resistant coated member comprises a substrate composed of a material selected from among molybdenum, tantalum, tungsten, zirconium, aluminum, titanium, carbon, and alloys, oxide ceramics, non-oxide ceramics and carbide materials thereof, which is covered with a layer composed primarily of a rare earth-containing oxide. In addition to heat resistance, the coated member has good corrosion resistance and non-reactivity, making it highly suitable as a part for sintering or heat-treating metals and ceramics in a vacuum, an inert atmosphere or a reducing atmosphere.

Abstract: The invention discloses an efficient method for the formation of a highly corrosion- or etching-resistant thermal spray coating layer of a rare earth oxide or rare earth-based composite oxide by a process of plasma thermal spray method by using a unique thermal spray powder consisting of granules of the oxide. The thermal spray granules are characterized by a specified average particle diameter of 5 to 80 &mgr;m with a specified dispersion index of 0.1 to 0.7 and a specified BET specific surface area of 1 to 5 m2/g as well as a very low content of impurity iron not exceeding 5 ppm by weight as oxide. The flame spat powder used here is characterized by several other granulometric parameters including globular particle configuration, particle diameter D90, bulk density and cumulative pore volume.

Abstract: The invention discloses a method for the preparation of a rare earth hydroxide powder in which, different from the conventional wet-process hydroxide precipitation method in an aqueous solution of a rare earth salt by the addition of an alkali, a powder of a rare earth oxide is brought into contact with a limited amount of water in the form of either liquid or vapor and kept in contact with water at a temperature of 30 to 200° C. The thus prepared rare earth hydroxide powder is characterized by a small crystallite diameter not exceeding 40 nm and outstandingly low contents of impurity chlorine and nitrate ions originating in the starting rare earth salt in the hydroxide prepared by the conventional wet-process method.

Abstract: Composite fine particles each having a nickel base core whose surface is coated with an oxide are effective for improving shrinkage upon firing and metal oxidation during binder burnout. The nickel base core has the formula: Ni(1-a-b)ZaZ′b wherein Z is Ag, Au, Co, Cu, Pd or a mixture of any, Z′ is Li, K, Na, B, P or a mixture of any, 0≦a≦0.4, 0≦b≦0.1 (weight proportion), and a+b>0, and the coating oxide is an oxide of Ag, Ba, Co, Cu, Ni, Sn, Ti, Zr, rare earth elements including Y, Pd or a mixture of any.

Abstract: The invention discloses an efficient method for the formation of a highly corrosion- or etching-resistant thermal spray coating layer of a rare earth oxide or rare earth-based composite oxide by a process of plasma thermal spray method by using a unique thermal spray powder consisting of granules of the oxide. The thermal spray granules are characterized by a specified average particle diameter of 5 to 80 &mgr;m with a specified dispersion index of 0.1 to 0.7 and a specified BET specific surface area of 1 to 5 m2/g as well as a very low content of impurity iron not exceeding 5 ppm by weight as oxide. The flame spat powder used here is characterized by several other granulometric parameters including globular particle configuration, particle diameter D90, bulk density and cumulative pore volume.

Abstract: The invention discloses an efficient method for the formation of a highly corrosion- or etching-resistant thermal spray coating layer of a rare earth oxide or rare earth-based composite oxide by a process of plasma thermal spray method by using a unique thermal spray powder consisting of granules of the oxide. The thermal spray granules are characterized by a specified average particle diameter of 5 to 80 &mgr;m with a specified dispersion index of 0.1 to 0.7 and a specified BET specific surface area of 1 to 5 m2/g as well as a very low content of impurity iron not exceeding 5 ppm by weight as oxide. The flame spat powder used here is characterized by several other granulometric parameters including globular particle configuration, particle diameter D90, bulk density and cumulative pore volume.

Abstract: An object of the present invention is to provide excellent members which have high purity, good thermal shock resistance and high mechanical strength and which are useful, for example, as heat-treating jigs for use in the manufacture of semiconductors and components of etching equipment used in a process for the manufacture of semiconductors or liquid crystal devices. Specifically, the present invention provides a rare earth-containing oxide member comprising a substrate comprising at least one selected from group consisting of C, Si, Al, Ni, Ti, Fe, Mo, Ta and W, or an alloy comprising at least one selected from group consisting of Si, Al, Ni, Ti, Fe, Mo, Ta and W; and a compound oxide laminated to the substrate, the compound oxide comprising a rare earth element (inclusive of Y) and Al and having a composition of 40 to 90 mole % of rare earth oxide and 10 to 60 mole % of Al2O3, based on the total amount of the oxides.

Abstract: A coated member in which a substrate made of Mo, Ta, W, Zr or carbon is coated with a yttrium-containing oxide is sufficiently heat resistant to use as a jig in the sintering or heat treatment of metals or ceramics in vacuum or an inert or reducing atmosphere at a temperature below 1300° C.

Abstract: A heat-resistant coated member comprises a substrate composed of a material selected from among molybdenum, tantalum, tungsten, zirconium, aluminum, titanium, carbon, and alloys, oxide ceramics, non-oxide ceramics and carbide materials thereof, which is covered with a layer composed primarily of a rare earth-containing oxide. In addition to heat resistance, the coated member has good corrosion resistance and non-reactivity, making it highly suitable as a part for sintering or heat-treating metals and ceramics in a vacuum, an inert atmosphere or a reducing atmosphere.

Abstract: Rare earth oxide particles having an average particle diameter of 3-20 &mgr;m, a dispersion index of up to 0.4, and an aspect ratio of up to 2 are suitable for thermal spraying. Despite their high melting point, the rare earth oxide particles of high purity can form an adherent coating by thermal spraying.

Abstract: Composite fine particles each having a nickel base core whose surface is coated with an oxide are effective for improving shrinkage upon firing and metal oxidation during binder burnout. The nickel base core has the formula: Ni(1-a-b)ZaZ′b wherein Z is Ag, Au, Co, Cu, Pd or a mixture of any, Z′ is Li, K, Na, B, P or a mixture of any, 0≦a≦0.4, 0≦b≦0.1 (weight proportion), and a+b>0, and the coating oxide is an oxide of Ag, Ba, Co, Cu, Ni, Sn, Ti, Zr, rare earth elements including Y, Pd or a mixture of any.

Abstract: The invention discloses a method for the preparation of a rare earth hydroxide powder in which, different from the conventional wet-process hydroxide precipitation method in an aqueous solution of a rare earth salt by the addition of an alkali, a powder of a rare earth oxide is brought into contact with a limited amount of water in the form of either liquid or vapor and kept in contact with water at a temperature of 30 to 200° C. The thus prepared rare earth hydroxide powder is characterized by a small crystallite diameter not exceeding 40 nm and outstandingly low contents of impurity chlorine and nitrate ions originating in the starting rare earth salt in the hydroxide prepared by the conventional wet-process method.

Abstract: The invention discloses an efficient method for the formation of a highly corrosion— or etching-resistant thermal spray coating layer of a rare earth oxide or rare earth-based composite oxide by a process of plasma thermal spray method by using a unique thermal spray powder consisting of granules of the oxide. The thermal spray granules are characterized by a specified average particle diameter of 5 to 80 &mgr;m with a specified dispersion index of 0.1 to 0.7 and a specified BET specific surface area of 1 to 5 m2/g as well as a very low content of impurity iron not exceeding 5 ppm by weight as oxide. The flame spat powder used here is characterized by several other granulometric parameters including globular particle configuration, particle diameter D90, bulk density and cumulative pore volume.

Abstract: Disclosed is a corrosion-resistant material capable of withstanding attack of a halogen-containing corrosive gas such as sulfur hexafluoride or a plasma thereof. The corrosion-resistant material is characterized in that at least the surface layer thereof is formed from a sintered body of a composite oxide having a crystalline structure of garnet and having a composition expressed by the formula Ln3Al5O12, in which Ln is a rare earth element or a combination of rare earth elements selected from the group consisting of dysprosium, holmium, erbium, thulium, ytterbium and lutetium, the material having a surface roughness Ra not exceeding 1 &mgr;m and the sintered body having a porosity not exceeding 3%.

Abstract: Proposed is a powder of ytterbium phosphate having a non-stoichiometric phosphorus to ytterbium molar ratio of 1.08 to 2.0 and having a specified average particle diameter and specified diameter of the crystallites forming the particles. The powder is useful as an infrared-absorbing pigment in a printing ink invisible to naked eyes but detectable by an infrared detecting means for printing of stealth bar code patterns. The ytterbium phosphate powder can be prepared in a convenient and inexpensive method utilizing the precipitation reaction by mixing an aqueous phosphoric acid solution and ytterbium salt solution under specified conditions followed by calcination of the precipitates at a specified temperature and pulverization of the calcined precipitates to give the specified average particle diameter.

Abstract: Disclosed are a hydrogen storage alloy which contains carbon in a proportion of from 30 to 500 ppm and is represented by the stoichiometric formula A.sub.x B.sub.5.0, wherein A is La or a mixture of La with at least one rare earth metal other than La, B is at least one metal selected from a group consisting of Al, Co, Cr, Cu, Fe, Mn, Ni, Ti, V, Zn and Zr, and x is a rational number in the range 0.95.ltoreq..times..ltoreq.1.00; and has a texture in which only the intermetallic compound phase named AB.sub.5 phase is present and every other intermetallic compound phase is absent: and a method of producing said alloy and an electrode using the same.