A circuit board includes a metal circuit plate, a metallic heat diffusing plate disposed below the metal circuit plate and having an upper surface and a lower surface, a metallic heat dissipating plate below the heat diffusing plate, an insulating substrate disposed between the metal circuit plate and the heat diffusing plate, and an insulating substrate disposed between the heat diffusing plate and the heat dissipating plate. A grain diameter of metal grains contained in the heat diffusing plate decreases from each of the upper surface and the lower surface of the heat diffusing plate toward a center portion of the heat diffusing plate in a thickness direction.

Methods of forming a metallic-ceramic brazed joint are disclosed herein. The method of forming the brazed joint includes deoxidizing the surface of metallic components, assembling the joint, heating the joint to fuse the joint components, and cooling the joint. In certain embodiments, the brazed joint includes a conformal layer. In further embodiments, the brazed joint has features in order to reduce stress concentrations within the joint.

A bonded body according to an embodiment includes a ceramic substrate, a copper plate, and a bonding layer that is located on at least one surface of the ceramic substrate and bonds the ceramic substrate and the copper plate. The bonding layer includes titanium. The bonding layer includes first and second regions; the first region includes a layer including titanium as a major component; the layer is formed at an interface of the bonding layer with the ceramic substrate; and the second region is positioned between the first region and the copper plate. The bonded body has a ratio M1/M2 of a titanium concentration M1 at % in the first region and a titanium concentration M2 at % in the second region that is not less than 0.1 and not more than 5 when the Ti concentrations are measured by EDX respectively in measurement regions in the first and second regions.

Disclosed are a multi-layer composite ceramic plate and a manufacturing method thereof. The composite ceramic plate includes at least one basic sandwich structure. The manufacturing method includes: preparing a sheet-like green body with ceramic powders; pre-sintering the green body at a pre-sintering temperature lower than the sintering temperature to obtain a pre-sintered ceramic member with certain strength; forming a metal electrode layer on an upper surface of the pre-sintered ceramic member; placing the pre-sintered ceramic member in a mold, with the upper surface coated with the metal electrode layer facing upwards; providing a ceramic precursor layer on the upper surface of the pre-sintered ceramic member; carrying out hot-pressing sintering in the axial direction of the pre-sintered ceramic member at the sintering temperature to form an integral structure, wherein by the hot-pressing sintering, a second ceramic layer is formed by the pre-sintered ceramic member, a first ceramic layer is formed by the ceramic precursor layer, and the metal electrode layer is located between the first ceramic layer and the second ceramic layer to from a basic sandwich structure together with the first ceramic layer and the second ceramic layer.

A bonded assembly according to the present embodiment, includes a metal plate and a ceramic substrate bonded to each other through a bonding layer containing Ag. In the bonded assembly, in a measurement region that is formed in a cross section formed by a thickness direction of the bonding layer and an orthogonal direction thereto, and that has a size of a length in the thickness direction of the bonding layer×a length of 200 μm in the orthogonal direction, a Ag-rich region having a Ag concentration of 60 at % or more has an area ratio of 70% or less to a Ag-poor region having a Ag concentration of 50 at % or less.

A method for manufacturing a power module substrate includes a first lamination step of laminating a ceramic substrate and a copper sheet through an active metal material and a filler metal having a melting point of 660° C. or lower on one surface side of the ceramic substrate; a second lamination step of laminating the ceramic substrate and an aluminum sheet through a bonding material on the other surface side of the ceramic substrate; and a heating treatment step of heating the ceramic substrate, the copper sheet, and the aluminum sheet laminated together, and the ceramic substrate and the copper sheet, and the ceramic sheet and the aluminum sheet are bonded at the same time.

The invention relates to a process for producing a metal-ceramic substrate (1), comprising: —providing a ceramic element (10), a metal ply (40) and at least one metal layer (30), —forming an ensemble (18) of the ceramic element (10), the metal ply (40) and the at least one metal layer (30), —forming a gas-tight container (30) surrounding the ceramic element (10), wherein the at least one metal layer (30) is arranged between the ceramic element (10) and the metal ply (40) in the container, and—forming the metal-ceramic substrate (1) by hot isostatic pressing.

The disclosure provides seals for devices that operate at elevated temperatures and have reactive metal vapors, such as lithium, sodium or magnesium. In some examples, such devices include energy storage devices that may be used within an electrical power grid or as part of a standalone system. The energy storage devices may be charged from an electricity production source for later discharge, such as when there is a demand for electrical energy consumption.

A bonded body of the present invention includes a ceramic member formed of ceramics and a Cu member formed of Cu or a Cu alloy. In a bonding layer formed between the ceramic member and the Cu member, an area ratio of a Cu.sub.3P phase in a region extending by up to 50 μm toward the Cu member side from a bonding surface of the ceramic member is equal to or lower than 15%.

A bonded body of the present invention includes a ceramic member formed of ceramics and a Cu member formed of Cu or a Cu alloy. In a bonding layer formed between the ceramic member and the Cu member, an area ratio of a Cu.sub.3P phase in a region extending by up to 50 μm toward the Cu member side from a bonding surface of the ceramic member is equal to or lower than 15%.