Abstract: A catalyst for an oxygen evolution reaction has a higher and longer-life catalytic activity than that of the conventional and expensive noble metal oxide catalysts, such as RuO2 and IrO2. An A-site ordered perovskite oxide catalyst (such as CaCu3Fe4O12 and CaMn3Mn4O12 etc.) as an oxygen evolution reaction catalyst is excellent in cost effectiveness. The catalyst has a high catalytic activity compared with a noble metal oxide catalyst, and a long repetition use life since it is extremely stable also under the oxidative reaction conditions. Use of the catalyst is expected to the important energy conversion reactions such as a charge reaction of a metal-air battery, an anode oxygen evolution reaction in the case of a direct water decomposition reaction by sunlight, etc.

Abstract: A catalyst for an oxygen evolution reaction has a higher and longer-life catalytic activity than that of the conventional and expensive noble metal oxide catalysts, such as RuO2 and IrO2. An A-site ordered perovskite oxide catalyst (such as CaCu3Fe4O12 and CaMn3Mn4O12 etc.) as an oxygen evolution reaction catalyst is excellent in cost effectiveness. The catalyst has a high catalytic activity compared with a noble metal oxide catalyst, and a long repetition use life since it is extremely stable also under the oxidative reaction conditions. Use of the catalyst is expected to the important energy conversion reactions such as a charge reaction of a metal-air battery, an anode oxygen evolution reaction in the case of a direct water decomposition reaction by sunlight, etc.

Abstract: An inexpensive Cu-diamond based composite material having excellent heat conductivity and heat resistance. Conventionally, an infiltration method does not provide a Cu-diamond based composite material having high heat conductivity; an ultrahigh pressure method is expensive; and electric current pressure sintering provides relatively high heat conductivity, a low cost, but insufficient heat resistance. A Cu-diamond based solid phase sintered body contains 2 vol % or more and 6 vol % or less of Cr, and 30 vol % or more and 80 vol % or less of diamond particles containing 20 vol % or more of a high crystallinity diamond component.

Abstract: In a composite roll for manufacturing heat transfer tubes that has two or more grooving rolls having protrusions where at least one of cross sectional shapes, lead angles relative to a rotation direction and sizes is different, by coaxially combining the rolls to form multiple types of grooves on a surface of metallic strips by pressing against the metallic strips, the composite roll for manufacturing heat transfer tubes of the present invention is characterized in that the two or more grooving rolls are joined in one body in a mutually surface contacting state. It is also preferable that the two or more grooving rolls are joined by diffusion bonding.

Abstract: In a composite roll for manufacturing heat transfer tubes that has two or more grooving rolls having protrusions where at least one of cross sectional shapes, lead angles relative to a rotation direction and sizes is different, by coaxially combining the rolls to form multiple types of grooves on a surface of metallic strips by pressing against the metallic strips, the composite roll for manufacturing heat transfer tubes of the present invention is characterized in that the two or more grooving rolls are joined in one body in a mutually surface contacting state. It is also preferable that the two or more grooving rolls are joined by diffusion bonding.

Abstract: Provided is a heat sink which has excellent processability and is economical, even though it employs diamond, as well as, a process for producing the same. The heat sink is molded using a composition obtained by adding a diamond powder of 0.1 to 100 .mu.m high-purity diamond particles to cemented carbide primarily of WC and a balance of at least one metal selected from Co, Ni and Fe along with impurities. The proportion of the diamond powder admixed relative to the cemented carbide is preferably 5 to 90%, and the diamond heat sink is produced by sintering the particulate mixture of diamond, WC, Co, etc. at a temperature of 1200.degree. to 1500.degree. C. under a pressure of 3 to 6 GPa.

Abstract: This invention relates to a method of producing a corrosion-, heat- and wear-resistant member which comprises packing an atomized powder of a high-carbon high-chromium steel into a capsule, heating the capsule packed with the powder, then extruding the capsule packed with the powder to obtain a stock not containing carbide grains greater than 3 .mu.m, working the stock, polishing a surface of the stock, and evaporating a film of TiC and/or TiN onto the polished surface, and further a corrosion-, heat- and wear-resistant member produced by the method. The corrosion-, heat- and wear-resistant member according to this invention is suitable for being members for tools used under extremely severe conditions, such as various tools for can manufacturing, molding tools for reinforced plastics, etc.

Abstract: A method for manufacturing a diamond tool having a shank, comprising accurately arranging a diamond chip on an upper surface of a base body in such a manner that the cutting edge of the chip projects from the end of the body by a predetermined distance, provisionally securing the chip to the upper surface of the body by means of an adhesive, fitting the body and an insert having an exposed clayish fixture in a U-shaped channel of a lower die to penetrate and position the cutting edge portion of the chip into the fixture of the insert, passing an upper die against the lower die after the fixture is cured, charging a predetermined amount of powder metals into a vertical hole formed in the upper die, pressurizing the powder metals by a press rod which is inserted in the vertical hole while heating the upper and lower dies in order to sinter the powder metals on the upper surface of the body and in the U-shaped channel of the lower die, thereby to rigidly fix the chip to the body, and shaping the body so as to pr

Abstract: If cemented carbide products such as hot rolling-mill rolls, plugs and dies can be made of the powder reclaimed from scrapped cemented carbide products and the virgin powder of cemented carbide, it is possible to obtain cemented carbide products lower in price and capable of meeting the requirements of severe working conditions.