In a copper-ceramic bonded body of the present invention, at a bonding interface of a copper member and a ceramic member, there are formed a nitride compound layer containing one or more nitride forming elements selected from Ti, Nb, Hf, and Zr, and an Ag—Cu eutectic layer, in order from the ceramic member side, the thickness of the nitride compound layer is 0.15 μm or more and 1.0 μm or less, an intermetallic compound phase formed of an intermetallic compound that contains the nitride forming element and Si is present between the copper member and the ceramic member, and Cu and Si are present at the grain boundary of the nitride compound layer.

This patent document relates to systems, structures, devices, and fabrication processes for ceramic matrix composites suitable for use in a nuclear reactor environment and other applications requiring materials that can withstand high temperatures and/or highly corrosive environments. In one exemplary aspect, a method of joining and sealing ceramic structures is disclosed. The method comprises forming a joint of a ceramic structure and an end plug using a sealing material, wherein the end plug has a hole that goes through a top surface and a bottom surface of the end plug; filling the ceramic structure with a desired gas composition through the hole; heating a material into a molten form using a heat source; and directing the material into the hole, wherein the material solidifies to seal the end plug.

A ceramic circuit substrate having high bonding performance and excellent thermal cycling resistance properties, having a circuit pattern provided on a ceramic substrate with a braze material layer interposed therebetween, and a protruding portion formed by the braze material layer protruding from the outer edge of the circuit pattern, wherein: the braze material layer includes Ag, Cu, Ti, and Sn or In; and an Ag-rich phase is formed continuously for 300 m or more, towards the inside, from an outer edge of the protruding portion, along a bonding interface between the ceramic substrate and the circuit pattern, and has a bonding void ratio of 1.0% or less.

A joint structure jointing a ceramic member and a metal member is a joint structure jointing a ceramic member and a metal member that are provided in a device provided on a portion through which gas passes. The joint structure has a joint portion that joints the ceramic member and the metal member. The joint portion includes a glass portion made of a glass and a metal solder portion having higher corrosion resistance with respect to the gas than the glass. An area where the metal solder portion contacts to the gas is larger than an area where the glass portion contacts to the gas.

This patent document relates to systems, structures, devices, and fabrication processes for ceramic matrix composites suitable for use in a nuclear reactor environment and other applications requiring materials that can withstand high temperatures and/or highly corrosive environments. In one exemplary aspect, a method of joining and sealing ceramic structures is disclosed. The method comprises forming a joint of a ceramic structure and an end plug using a sealing material, wherein the end plug has a hole that goes through a top surface and a bottom surface of the end plug; filling the ceramic structure with a desired gas composition through the hole; heating a material into a molten form using a heat source; and directing the material into the hole, wherein the material solidifies to seal the end plug.

In a copper-ceramic bonded body of the present invention, at a bonding interface of a copper member and a ceramic member, there are formed a nitride compound layer containing one or more nitride forming elements selected from Ti, Nb, Hf, and Zr, and an AgCu eutectic layer, in order from the ceramic member side, the thickness of the nitride compound layer is 0.15 m or more and 1.0 m or less, an intermetallic compound phase formed of an intermetallic compound that contains the nitride forming element and Si is present between the copper member and the ceramic member, and Cu and Si are present at the grain boundary of the nitride compound layer.

A method for fabricating assemblies that includes providing a first component that further includes silicon carbide and that has an upper portion and a tapered lower portion; providing a second component that further includes silicon carbide and that has an upper portion that is adapted to receive the tapered lower portion of the first component; providing a predetermined amount of multiphase AlSi braze foil; grinding the AlSi braze foil into a powder; mixing a predetermined amount of braze paste binder with the AlSi powder to form a slurry; uniformly applying the slurry to the tapered lower portion of the first component; uniformly applying the slurry to the upper portion of the second component and inserting the tapered lower portion of the first component into the upper portion of the second component; and heating the applied slurry to a temperature of 725 C. to 1450 C. for a predetermined period of time.

A method for fabricating assemblies that includes providing a first component that further includes silicon carbide and that has an upper portion and a tapered lower portion; providing a second component that further includes silicon carbide and that has an upper portion that is adapted to receive the tapered lower portion of the first component; providing a predetermined amount of multiphase AlSi braze foil; grinding the AlSi braze foil into a powder; mixing a predetermined amount of braze paste binder with the AlSi powder to form a slurry; uniformly applying the slurry to the tapered lower portion of the first component; uniformly applying the slurry to the upper portion of the second component and inserting the tapered lower portion of the first component into the upper portion of the second component; and heating the applied slurry to a temperature of 725 C. to 1450 C. for a predetermined period of time.

A cutting tool includes a supporting body and a cBN or PCD cutting edge tip attached to the supporting body via a 5-150 ?m braze joint. The supporting body is cemented carbide having 3-25 wt % of a metallic binder, optionally up to 25 wt % of carbides or carbonitrides of one or more elements of group 4, 5, or 6, and the rest WC. The metallic binder includes at least 40 wt % Ni, and the braze joint has, in the order from the supporting body, a first layer of TiC situated next thereto, with an average thickness of 10-400 nm, a second layer, with an average thickness of 0.5-8 ?m, having in average at least 5 wt % metallic Ni, in average 25-60 wt % metallic Cu and in average 15-45 wt % metallic Ti, and a third layer, with an average thickness of 4-145 ?m, having metallic Ag and metallic Cu.

A method for fabricating assemblies includes providing first and second components that include ceramic, metal, or composite; positioning a multiphase joining interlayer between the first and second components, wherein the joining interlayer includes a first phase that melts at a first temperature and a second phase interspersed throughout the first phase, and wherein the second phase melts at a second temperature that is lower than the melting temperature of the first phase; and heating the joining interlayer to a temperature in the range of 725 C. to 1450 C. for a predetermined period of time to soften the first phase and melt the second phase, wherein the first phase remains in a solid or a semi-solid state, and wherein the second phase segregates to the boundaries of the first phase and transforms the joining interlayer into a substantially porosity-free adherent material that joins the first component to the second component.