Abstract: A first tungsten-based sintered material of the present invention comprises Ni in a range from 0.2 to 1.5% by mass, Y2O3 in a range from 0.1 to 1% by mass, and optionally, (a) VC in a range from 0.05 to 0.5% by mass and/or (b) Co and/or Fe in a range from 0.01 to 5% by mass, the balance being tungsten (W); W phases are sinter-bonded; Ni phase or Ni—Co/Fe alloy phase which has the largest particle diameter of 5 ?m or less and Y2O3 having the largest particle diameter of 5 ?m or less are distributed at boundaries of the W phases; and the largest particle diameter of the W phase is 30 ?m or less. The first tungsten-based sintered material is preferably used for a hot press mold for optical glass lenses.

Abstract: A first tungsten-based sintered material of the present invention comprises Ni in a range from 0.2 to 1.5% by mass, Y2O3 in a range from 0.1 to 1% by mass, and optionally, (a) VC in a range from 0.05 to 0.5% by mass and/or (b) Co and/or Fe in a range from 0.01 to 5% by mass, the balance being tungsten (W); W phases are sinter-bonded; Ni phase or Ni—Co/Fe alloy phase which has the largest particle diameter of 5 ?m or less and Y2O3 having the largest particle diameter of 5 ?m or less are distributed at boundaries of the W phases; and the largest particle diameter of the W phase is 30 ?m or less. The first tungsten-based sintered material is preferably used for a hot press mold for optical glass lenses.

Abstract: An internal gear oil pump made of Al alloys having less mutual damage property and superior wear resistance is provided. The internal gear oil pump has a casing with a gear compartment, a drive gear, and a driven gear, all of which are the structural members of the internal gear oil pump. The casing is constituted of an Al-alloy casting. The drive gear and the driven gear are constituted of a hot plastic working material of Al—Si alloy powder. The hot plastic working material is constituted of an Al—Si alloy having a structure in which unit crystal phases are dispersed in a base matrix by 10 to 40 area percent. by the structural observation with an optical microscope, the unit. crystal phases being harder than the base matrix. The base matrix is constituted of an Al—Si alloy which contains, on weight basis, 10% to 18% Si, 4% to 8% Fe, 1% to 3% Ni, 1% to 3% Cr, and the balance being Al and incidental impurities.

Abstract: A highly wear-resistant aluminum-based composite alloy has improved wear resistant itself and the wear amount of the opposed Fe-based material is decreased as compared with the conventional wear-resistant aluminum alloys. The inventive composite alloy has a structure that at least either a dispersing phase selected from the group consisting of hard fine particles or a solid-lubricant particles having average diameter of 10 um or less is dispersed in an aluminum-alloy matrix which contains quasi-crystals.

Abstract: A ceramic circuit board with a heat sink which has a long life under heat cycles. First and second aluminum plates are laminated and bonded onto both sides of a ceramic substrate through Al--Si-based brazing solders, respectively. A heat sink formed of an AlSiC-based composite material is laminated and bonded onto a surface of the first aluminum plate. The ceramic substrate is formed of AlN, Si.sub.3 N.sub.4 or Al.sub.2 O.sub.3. An Al alloy in the heat sink has an Al purity of 80-99% by weight, and the first or second aluminum plate has an Al purity not less than 99.98% by weight. The heat sink is laminated and bonded onto the first aluminum plate through the Al alloy in the heat sink.

Abstract: The present invention relates to a Cu-based sintered alloy which has a composition containing: Zn: 10-40%; Al: 0.3%-6% oxygen: 0.03-1%; any one selected, as an additional element from the group including at least one of Fe, Ni and Co: 0.1-5%, Mn: 0.1-5%, Si: 0.1-3%, and at least one of W and Mo: 0.1-3%; and the remainder including Cu and inevitable impurities. The alloy is superior in wear resistance particularly in air at temperatures ranging from the ordinary temperature to 400.degree. C., has high strength and high toughness, and further excels in the uniform temporal change characteristics with associated members, as evaluated by its friction coefficient. The invention relates also to parts for automotive equipment made of this Cu-base sintered alloy, such as synchronizer rings for transmission, valveguides for engines, bearings for turbo-chargers and so forth.