Abstract: Composite ceramics having a high strength, a high toughness and an excellent abrasion resistance, and a method of producing the same. The composite ceramics comprises 10 to 30 mass % of a zirconia crystal phase containing 9 to 12 mol % of CeO2 and 2.8 to 4.5 mol % of Y2O3; and 70 to 90 mass % of an alumina crystal phase, the zirconia crystal phase having an average crystal particle size of not larger than 1 ?m.

Abstract: Alumina/zirconia ceramics containing Al2O3 in an amount of not less than 65 mass % and ZrO2 in an amount of 4 to 34 mass %, and further containing TiO2, MgO and SiO2. The ceramics effectively suppresses the growth of shape isotropic particles of alumina, suppresses the growth of zirconia particles, and has a high strength and a high hardness. Besides, the ceramics containing SrO features a high fracture toughness.

Abstract: A thermally conductive compound which comprises 15 to 60 volume % of thermoplastic carrier resin consisting of a copolymer of a plasticizer with ethylene or of a polymer of the plasticizer, polyethylene and the copolymer, 40 to 85 volume % of thermally conductive filler particles dispersed in the carrier resin, and 0.5 to 5 weight % (for the filler particles) of a dispersing agent having (a) hydrophilic group(s) and (a) hydrophobic group(s). The thermally conductive compound has a high thermal conductivity and a plasticity in the range of temperatures of −40 to 50° C.

Abstract: An aluminous sintered product comprising 70 to 96% by weight of an alumina component and 4 to 30% by weight of additives, said additives including at least the one selected from oxides of elements of the Group 5a of periodic table and at least the one selected from oxides of metals of the iron family and oxides of manganese, titanium, calcium, magnesium, chromium and silica, and said aluminous sintered product exhibiting a volume resistivity of from 1.times.10.sup.7 to 1.times.10.sup.13 .OMEGA.-cm over a temperature range of from 25.degree. to 75.degree. C. and an absolute value of the temperature coefficient of volume resistivity of not larger than 1.8%/.degree.C. under the application of high voltages.

Abstract: A dielectric ceramic composition having a high dielectric constant and a coefficient of thermal expansion nearly comparable with that of alumina, and a package for packaging semiconductor. The dielectric ceramic composition contains 0.1 to 0.6 parts by weight of manganese reckoned as an oxide per 100 parts by weight of chief components of the formula xTiO.sub.2 .cndot.yMgO.cndot.zSrO or of the formula xTiO.sub.2 .cndot.yMgO.cndot.zCaO wherein x, y and z are numerals that lie within given ranges. The package for packaging semiconductor comprises a package body composed of alumina and having a semiconductor-mounting portion, and a capacitor made up of a dielectric layer and an electrode layer provided on said semiconductor-mounting portion, wherein the dielectric layer is composed of the TiO.sub.2 --MgO--SrO--MnO.sub.2 -type dielectric ceramic or the TiO.sub.2 --MgO--CaO--MnO.sub.2 -type dielectric ceramic.

Abstract: A package for a semiconductor device comprising (i) a high dielectric layer composed of an alumina particles, a high permittivity-imparting agent in particles selected from (a) W or Mo, (b) Re and (c) zirconia and a glass plase comprising alumina and at least one component selected from silica, alkaline earth metal components, and rare earth device components present in their grain boundaries, (ii) a pair of electrode layers comprising as a main component a metal selected from W and Mo provided on both sides of the high dielectric layer, and (iii) insulation layers composed of alumina particles and a glass phase composed of alumina and at least one component selected from silica, alkaline earth metal components and rare earth device components, the insulation layers being provided so as to sandwich the electrode layers and the dielectric layer.