According to one embodiment, when a DSC curve is measured using a differential scanning calorimeter (DSC) for a brazing material for bonding a ceramic substrate and a metal plate, the brazing material has an endothermic peak within a range of not less than 550° C. and not more than 700° C. in a heating process. The brazing material favorably includes Ag, Cu, and Ti. The brazing material favorably has not less than two of the endothermic peaks within a range of not less than 550° C. and not more than 650° C. in the heating process.

A joined material and a method of manufacturing the joined material are provided which enable a metal layer and a carbon material layer to be easily joined to each other while making the thickness of the metal layer larger and which can inhibit failure. A joined material includes a CFC layer (3) and a tungsten layer (4) that are joined to each other. A sintered tungsten carbide layer (5), a mixed layer (6) of SiC and WC, and SiC and WC (7) that have been sintered while intruding into the CFC layer (3), are formed between the CFC layer (3) and the tungsten layer (4), and these layers (3, 4, 5, 6, and 7) are joined to each other by sintering.

A ceramic circuit substrate having a metal plate bonded, by a bonding braze material, to at least one main surface of a ceramic substrate, wherein the bonding braze material contains, as metal components, 0.5 to 4.0 parts by mass of at least one active metal selected from among titanium, zirconium, hafnium, and niobium, with respect to 100 parts by mass, in total, of 93.0 to 99.4 parts by mass of Ag, 0.1 to 5.0 parts by mass of Cu, and 0.5 to 2.0 parts by mass of Sn; and Cu-rich phases in a bonding braze material layer structure between the ceramic substrate and the metal plate have an average size of 3.5 μm or less and a number density of 0.015/μm2 or higher. A method for producing a ceramic circuit substrate includes bonding at a temperature of 855 to 900° C. for a retention time of 10 to 60 minutes.

A bonded substrate includes: a silicon nitride ceramic substrate; a copper plate; and a bonding layer bonding the copper plate to the silicon nitride ceramic substrate, wherein the bonding layer has a first interface in contact with the silicon nitride ceramic substrate and a second interface in contact with the copper plate, and contains a nitride and a silicide of an active metal as at least one metal selected from the group consisting of titanium and zirconium, an atomic fraction of nitrogen of the bonding layer is greatest at the first interface and is smallest at the second interface, and a sum of atomic fractions of the active metal and silicon of the bonding layer is smallest at the first interface and is greatest at the second interface.

A ceramic structure includes a base body, and a thermoelectric device having a part in directly contact with the base body. The base body is a ceramic consisting of aluminum oxide. The thermoelectric device comprises a conductor part that is a sintered body having an alloy of tungsten and rhenium, as a main component, and including nickel oxide, aluminum oxide and silicon dioxide.

A thermoelectric conversion element includes an element body formed of a thermoelectric conversion material of a silicide-based compound, and electrodes each formed on one surface of the element body and the other surface opposite the one surface. The electrodes are formed of a sintered body of a copper silicide, and the electrodes and the element body are directly joined.

According to one embodiment, a method for manufacturing a ceramic circuit board is disclosed. The ceramic circuit board includes a copper plate bonded to at least one surface of a ceramic substrate via a brazing material layer including Ag, Cu, and a reactive metal. The method includes: preparing a ceramic circuit board in which a copper plate is bonded on a ceramic substrate via a brazing material layer, and a portion of the brazing material layer is exposed between a pattern shape of the copper plate; a first chemical polishing process of chemically polishing the portion of the brazing material layer; and a first brazing material etching process of etching the chemically polished portion of the brazing material layer by using an etchant having a pH of 6 or less and including one type or two types selected from hydrogen peroxide and ammonium peroxodisulfate.

A method of forming one or more high temperature co-fired ceramic articles, comprising the steps of:— a) forming a plurality of green compacts, by a process comprising dry pressing a powder comprising ceramic and organic binder to form a green compact; b) disposing a conductor or conductor precursor to at least one surface of at least one of the plurality of green compacts to form at least one patterned green compact; c) assembling the at least one patterned green compact with one or more of the plurality of green compacts or patterned green compacts or both to form a laminated assembly; d) isostatically pressing the laminated assembly to form a pressed laminated assembly; e) firing the pressed laminated assembly at a temperature sufficient to sinter the ceramic layers together.

A substrate includes a ceramic sintered body, a first circuit plate and a second circuit plate. The ceramic sintered body contains Al, Zr, Y and Mg. In the ceramic sintered body, the Mg content in terms of MgO is S1 mass % and the Zr content in terms of ZrO.sub.2 is S2 mass %, a following formula (1) is established. When a thickness of the first circuit plate is T1 mm, a thickness of the second circuit plate is T2 mm, and a thickness of the ceramic sintered body is T3 mm, following formulas (2), (3), and (4) are established. Formula (1): −0.004×S2+0.171<S1<−0.032×S2+1.427; Formula (2): 1.7<(T1+T2)/T3<3.5; Formula (3): T1≥T2; and Formula (4): T3≥0.25.

An aluminum alloy member is made of an aluminum alloy having a Mg concentration set in a range of 0.4 mass % or more and 7.0 mass % or less and a Si concentration set to less than 1 mass %, the aluminum alloy member and a copper member are bonded to each other through solid-phase diffusion, and a compound layer made up of a first intermetallic compound layer that is disposed on the aluminum alloy member side and made of a θ phase of an intermetallic compound of Cu and Al, a second intermetallic compound layer that is disposed on the copper member side and made of a γ.sub.2 phase of an intermetallic compound of Cu and Al, and a Cu—Al—Mg layer provided between the first intermetallic compound layer and the second intermetallic compound layer is provided in a bonding interface between the aluminum alloy member and the copper member.