Abstract: A corrosion-resistant article of a magnesium material having the gloss of the metal substrate surface comprises an anodic oxide film formed on the external surface of an article of magnesium or a magnesium alloy, which never changes the gloss of the metal substrate and a colorless or colored transparent electrodeposition coating film on the anodic film. Such an article can be prepared by immersing an article of magnesium or a magnesium alloy in an electrolyte containing a phosphate and an aluminate to thus form an anodic oxide film through anodization of the surface of the article and forming a colorless or colored transparent electrodeposition coating film on the anodic film through electrodeposition coating.

Abstract: Composite nickel fine powder comprises metal nickel fine particles, at least one member attached to the surface of the fine particles and selected from the group consisting of oxides and double oxides containing at least one metal element selected from the group consisting of the Groups 2 to 14 of the Periodic Table and whose atomic number falls within the range of from 12 to 82, and a saturated or unsaturated fatty acid supported on the surface of the nickel fine particles provided thereon with the oxide and/or double oxide attached thereto. The composite nickel fine powder is excellent in resistance to heat shrinkage, has a high tap density, and has characteristic properties suitable for use as a material for making a conductive paste.

Abstract: Nickel powder herein disclosed has an average particle size, as determined by the observation with SEM, of not more than 1 &mgr;m, a particle density of not less than 8.0 g/cm3, and an average diameter of crystallites present in the nickel particles of not more than 550 Å. Moreover, a conductive paste for a multilayer ceramic capacitor comprises the foregoing nickel powder. The nickel powder and the conductive paste containing the same can control heat shrinkage while inhibiting any rapid oxidation and permit the production of a thin, uniform internal electrode for a multilayer ceramic capacitor without being accompanied by any crack formation and delamination during firing.

Abstract: Copper fine powder has an electrical resistance in its powdery state of not more than 1×10−3&OHgr;.cm; a BET specific surface area ranging from 0.15 to 0.3 m2/g; a tap density of not less than 4.5 g/cc; a product of the tap density and the particle size, of not less than 13, the particle size being calculated from the specific surface area and a particle size distribution observed in the microtrack measurement as expressed in terms of D50 and D90 ranging from 4 to 7 &mgr;m and 9 to 11 &mgr;m, respectively; and a weight loss through hydrogen-reduction of not more than 0.30%. The copper fine powder is prepared by adding an alkali hydroxide to an aqueous copper salt solution containing divalent copper ions maintained at not less than 55° C. in an amount of not less than the chemical equivalent to form cupric oxide; then gradually adding a reducing sugar to the reaction system while maintaining the temperature of the system to not less than 55° C.

Abstract: A nickel fine powder includes 0.02 to 1.0% by weight of magnesium and/or 0.02 to 0.1% by weight of calcium dispersed in the nickel. A method for preparing the nickel fine powder includes the steps of forming nickel hydroxide by mixing an aqueous solution containing a magnesium salt and/or a calcium salt and a nickel salt with an aqueous solution of sodium hydroxide and then reducing the hydroxide with a hydrazine reducing agent. The nickel fine powder has thermal shrinkage characteristics very close to those observed for ceramic substrates and is accordingly suitable as a material for producing an internal electrode for laminated ceramic condensers.

Abstract: A method for preparing nickel fine powder is herein disclosed, which comprises the steps of mixing an aqueous sodium hydroxide solution comprising, on the basis of the total weight of the sodium hydroxide present in the aqueous solution, 75 to 85% by weight of liquid caustic soda as specified in JIS K 1203 and 25 to 15% by weight, in total, of at least one of sodium hydroxide as specified in JIS K 8576 and solid caustic soda as specified in JIS K 1202, with an aqueous solution of nickel sulfate to form nickel hydroxide, then reducing the resulting nickel hydroxide with hydrazine and recovering nickel fine powder produced. The nickel fine powder prepared by the method has an average particle size of the primary particles ranging from 0.1 to 0.9 .mu.m, a D.sub.90 value of not more than 2.1 .mu.m and a tap density of not less than 3.5 g/cc.

Abstract: Herein disclosed is 6 indium tin oxide (ITO) fine powder whose crystal form is a corundum type one and which has a true specific gravity of not less than 6.5 g/cc, a green density of not less than 3.0 g/cc, and a Seebeck coefficient of less than 30 .mu.V/cc at ordinary temperature and less than 80 .mu.V/cc after heating at 200.degree. C. The ITO fine powder can be prepared by a method which comprises the steps of neutralizing an aqueous solution containing an indium salt and a tin salt with ammonia to thus control the pH of the reaction solution to the range of from 6.8 to 7.5; separating the resulting neutralized precipitates through filtration; drying and washing the precipitates; calcining the precipitates in the air at a temperature ranging from 550 to 700.degree. C.; and then reducing-burning at a temperature ranging from 350 to 450.degree. C. in a reducing atmosphere.

Abstract: Herein disclosed is a filter medium for molten metals which consists of a sintered body of a mixture comprising 100 parts by weight of at least one refractory grain selected from the group consisting of alumina particles and Al.sub.2 O.sub.3.MgO spinel crystal particles; and 5 to 25 parts by weight of an inorganic binder which comprises 60 to 90% by weight of Al.sub.2 O.sub.3.MgO spinel crystal powder, 5 to 12% by weight of B.sub.2 O.sub.3, and not more than 30% by weight of at least one oxide selected from the group consisting of Al.sub.2 O.sub.3, MgO and TiO.sub.2. The filter medium is used for filtering off solid impurities mixed in molten metals, in particular, molten aluminums.

Abstract: A silver sol comprises silver particles having a particle size ranging from 1 to 100 nm and a silver solid content ranging from 1 to 80% by weight. The silver sol can be prepared by a method comprising the steps of reacting a solution of a silver compound with a reducing agent at a temperature ranging from 5 to 50.degree. C. and a stirring speed falling within the range of from 1,000 to 10,000 rpm to form silver fine particles; recovering the resulting silver fine particles using a centrifugal separator; and then dispersing the silver fine particles in a medium to give a silver sol having a silver solid content ranging from 1 to 80% by weight. The silver sol or a coating material obtained by diluting the sol to a desired silver solid content and, if desired, adding a binder permits the formation of a transparent conductive film on, for instance, a cathode-ray tube while reducing the production cost.

Abstract: A fine particulate polishing agent comprises fine particles of a solid solution composed of single-crystal ceric oxide and silicon dioxide and fine particles of silicon dioxide. A slurry polishing agent comprising the fine particulate polishing agent can be prepared by a method which comprises the steps of mixing, with stirring, single-crystal ceric oxide fine particles, silica sol and a liquid; drying the mixture; subjecting the dried particulate material to a thermal treatment at a high temperature and then cooling the solid solution powder formed by the thermal treatment and composed of single crystal ceric oxide and silicon dioxide; again mixing the powder with silica sol and a liquid; and then subjecting the mixture to deagglomeration using a wet pulverizing mill to give a slurry.

Abstract: A zinc oxide fine particle-adhered composite material consists essentially of a substrate and zinc oxide fine particles adhered thereto. The composite material is characterized in that the zinc oxide fine particles deposited, from an aqueous medium, on the surface of the substrate are firmly adhered to the surface without using any binder and the zinc oxide fine particles are substantially exposed on the surface. The composite material is prepared by, for instance, a method which comprises the step of coming an aqueous suspension of zinc oxide fine particle in contact with a substrate to thus deposit the zinc oxide fine particles on the surface of the substrate. The composite material allows for the zinc oxide particles to sufficiently show their antibacterial, deodorizing, UV absorbing, photocatalytic, stain-proofing and purifying activities without any delay.

Abstract: Cerium oxide ultrafine particles consist essentially of cerium oxide single crystal grains having a grain size ranging from 10 to 80 nm and the cerium oxide ultrafine particles can be prepared by a method which comprises the steps of mixing, with stirring, an aqueous solution of cerous nitrate with a base in such a mixing ratio that the pH value of the mixture ranges from 5 to 10, then rapidly heating the resulting mixture up to a temperature of 70 to 100.degree. C. and maturing the mixture at that temperature. The cerium oxide ultrafine particles not only have an average particle size ranging from 10 to 80 nm, but also are uniform in the particle size and in the shape.

Abstract: A ceramic filter for filtering molten metals includes aggregate particles consisting of fused alumina and/or sintered alumina, and a binder material, wherein the binder is present in an amount of 10 to 22 parts, by weight, per 100 parts of the aggregate particles. The binder material consists of 15 to 25%, by weight, of Al.sub.2 O.sub.3, 35 to 52% of B.sub.2 O.sub.3, not less than 7% and less than 15% of Sio.sub.2, and the balance of MgO. The ceramic filter may be prepared by kneading 100 parts of aggregate particles consisting essentially of either or both of fused alumina and sintered alumina, 10 to 22 parts of the foregoing binder material, an appropriate amount of an organic binder and an appropriate amount of water; molding the resulting mixture; drying the molded mixture; and then firing the same at a temperature ranging from 1150 to 1300.degree. C.

Abstract: A process for producing spherical metal particles comprises the step of spraying a molten metal in a chamber filled with a refrigerant gas through a centrifugal atomizer, wherein the refrigerant gas is a composition comprising nitrogen and oxygen gases or nitrogen gas and air and the concentration of the oxygen ranges from 3 to 600 ppm on the basis of the weight of the composition. The production process of the present invention permits mass-production of fluent, spherical metal particles having a smooth surface, in low cost and excellent in dispersibility in a dispersing medium, which is required when the particles are used as a component for pastes or paint and varnishes, while using a small-sized chamber.

Abstract: A fine particulate polishing agent is based on cerium oxide and silicon oxide; a slurry polishing agent comprises the foregoing fine particulate polishing agent which can be prepared by a method which comprises the steps of mixing, with stirring, cerium oxide fine particles, silica sol and a liquid; drying the mixture; mixing the material with a liquid; and then subjecting the mixture to deagglomeration using a wet pulverizing mill to give a slurry. Preferably, the dried particulate material is subjected to a thermal treatment at a high temperature of 150.degree. to 1200.degree. C., preferably 800.degree. to 900.degree. C., thereby to produce a solid solution of cerium oxide and silicon oxide. The slurry polishing agent can ensure the achievement of surface roughness comparable to or superior to that achieved by the colloidal silica polishing agents and a high polishing rate at least comparable to that achieved by the conventional cerium oxide polishing agents.

Abstract: A printed circuit inner-layer copper foil having inverted tear drop-shaped fine nodules formed on both surfaces of a copper foil each having surface roughness Rz=1 to 3 .mu.m, the nodules having a length of 0.6 to 1.0 .mu.m and a maximum diameter of 0.2 to 0.8 .mu.m, and a process for producing said inner-layer copper foil.

Abstract: A process for surface-treating copper products, for example, a copper foil to be used for a copper-clad laminate, the resulting surface-treated copper product having a superior bond strength to a base material, resistant to etching solution, acids, etc., is provided, which process comprises electrically depositing a binary alloy consisting of 95 to 20% by weight of zinc and 5 to 80% by weight of nickel, on the surface of a copper product to form a coating layer, followed by laminating the resulting copper product onto a base material under heating and pressure, said binary alloy being converted during the lamination into a ternary alloy of zinc, nickel and copper constituting a boundary layer having a superior bond strength between the copper product and the base material.

Abstract: An active material for the positive electrode of a lead-accumulator and a lead-accumulator utilizing the active material are provided, the active material consisting of lead oxide as the principal component and at least one component selected from the group consisting of bismuth, bismuth compounds, thallium and thallium compounds as an additive which is effective to improve the energy utilization and the lifetime of the accumulator.

Abstract: An automatic working method of castings which comprises the steps of operating a die-casting machine to produce castings; operating a press to trim the castings; operating an industrial robot for carrying the castings from the die-casting machine to the press; operating an incasing device for successively supplying empty boxes to receive the castings; detecting the position of a casting set in the press; removing the casting from the press, in case the casting is improperly set; counting a number of castings delivered to the incasing device, and where the counted number is found to be smaller than a prescribed value, causing a deficient number of castings to be supplied to the incasing device; examining the operation of the machines undertaking the respective steps by a checking device attached to said machines; and, in case the operation of any of the machines is found to be defective, stopping said faulty machine.