Abstract: A GaAs single crystal substrate and an epitaxial wafer using the same suppress the generation of slips during growth of the epitaxial layer, and improve the breakdown withstanding characteristic of devices fabricated on such substrates. The GaAs single crystal substrate has a mean dislocation density in plane of at most 2×104 cm−2, a carbon concentration of 2.5 to 20.0×1015 cm−3, a boron concentration of 2.0 to 20.0×1016 cm−3, an impurity concentration other than carbon and boron of at most 1×1017 cm−3, an EL2 concentration of 5.0 to 10.0×1015 cm−3, resistivity of 1.0 to 5.0×108 &OHgr;·cm and a mean residual strain measured by photoelastic analysis of at most 1.0×10−5.

Abstract: A selectively case hardened steel article by low temperature carburization includes a body made of a chromium bearing nickel or ferrous based alloy (for example, stainless steel), a first portion of the body having a first hardness characteristic, and a second portion of the body having a second hardness characteristic; the second portion being less than the entire body and substantially free of carbides. One method for selective case hardening by low temperature carburization includes the steps of applying a carbon blocking mask over surface areas of the article that are not going to be carburized; activating those surface areas that are to be carburized; diffusing carbon into the activated surface areas at a temperature below which carbides readily form; and removing the carbon blocking mask.

Abstract: A joining alloy of the invention is based on Co, Ni, or their alloy, and contains 1.0 to 2.3% by mass of C and 15.5 to 34.7% by mass of W. Using HIP, the joining alloy in the form of a casting or powders is integrated with a WC--Co or WC--Ni type cemented carbide via diffusion joining. Using HIP, it is also possible to obtain a composite material having an integral structure in which a cemented carbide and the joining alloy, and the joining alloy and steel are joined together via diffusion joining. The joining alloy may additionally contain up to 30% by mass of Fe, up to 3% by mass of Si and up to 3% by mass of Mn as well as up to 10% by mass of at least one selected from Cr, Mo, V, Nb, Ti, Zr, and Ta. It is thus possible to obtain a joining alloy having an improved joining strength without producing a brittle phase therein even upon joined to the WC--Co or WC--Ni type cemented carbide, and its composite material.

Abstract: In accordance with the present invention, lithium secondary batteries excellent in charge/discharge characteristics, in particular in charge/discharge capacity and initial efficiency, and high in safety can be provided.

Abstract: A vapor deposition material which is a molded body composed of powdery zirconia and a stabilizer, the molded body having a fine structure constituted of a mixture of granules of zirconia particles and non-granulated particles; granules of particle diameter ranging from 20 to 300 .mu.m constitute 20 to 90% of the molded body; the granules of the zirconia particles containing substantially no stabilizer, and being constituted of crystals of a monoclinic phase and a cubic phase with a ratio of the monoclinic phase of 70% or higher; and the particles constituting the granules having an average particle diameter from 0.5 to 15 .mu.m. A process for vapor deposition which employs the above vapor deposition material, and further a member is provided of a base article coated directly, or with interposition of a third film, with a thin zirconia film.

Abstract: Electroceramic component having a component body (10), connection metallization coatings (2, 3) and also a protective encapsulation (15 to 18) made of two different materials on in each case two mutually opposite areas of the component body (10) which are free from the connection metallization coatings (2, 3).

Abstract: This invention is a plated steel sheet formed by laminating an iron oxide layer and a plated layer on a steel matrix in this order, in which excellent plating adhesion property can uniformly be given to a full surface of the steel sheet by disposing a connection portion made from a metallic iron or an iron alloy connecting the steel matrix to the plated layer in the iron oxide layer. Particularly, it can provide means for easily forming a plated layer having an excellent adhesion property through hot dipping can be given to steel sheets being difficult to conduct the hot dipping such as high-strength steel sheet, stainless steel sheet and the like.