A novel spot welding method for steel sheets and an aluminum alloy sheet, includes stacked sheet materials from a pair of opposing electrodes to join the sheet materials by resistance heating. The pair of opposing electrodes are in pressure contact with both outer surfaces of the sheet sets. The sheet sets include at least a first and second steel sheet, and an aluminum alloy sheet stacked in this order. A first energization step forms a molten pool between facing surfaces of the first and second steel sheets without melting the aluminum alloy sheet. A second energization step causes a melting reaction between facing surfaces of the second steel sheet and the aluminum alloy sheet. The first and second steel sheets are joined via a first nugget. The second steel sheet and the aluminum alloy sheet are joined via a second nugget including an intermetallic compound generated by the melting reaction.

A method for the joining of ceramic pieces includes applying a layer of titanium on a first ceramic piece and applying a layer of titanium on a second ceramic piece; applying a layer of nickel on each of the layers of titanium on the first ceramic piece and the second ceramic piece; applying a layer of nickel phosphorous to each of the layers of nickel on the first ceramic piece and the second ceramic piece; assembling the first ceramic piece and the second ceramic piece with the layers of titanium, nickel, and nickel phosphorous therebetween; pressing the layer of nickel phosphorous of the first ceramic piece against the layer of nickel phosphorous of the second ceramic piece; heating the first ceramic piece and the second ceramic piece to a joining temperature in a vacuum; and cooling the first ceramic piece and the second ceramic piece. A hermetic seal is formed between the first ceramic piece and the second ceramic piece.

An aluminum alloy brazing sheet used for brazing in an inert gas atmosphere without using flux includes a core material of aluminum or aluminum alloy, and a brazing material of aluminum alloy including Si of 4.0 mass % to 13.0 mass % and cladding one side surface or both side surfaces of the core material. One or both of the core material and the brazing material includes any one or two or more types of X atoms (X is Mg, Li, Be, Ca, Ce, La, Y, and Zr). The aluminum alloy brazing sheet is a brazing sheet in which oxide particles including the X atoms and having a volume change ratio of 0.99 or lower with respect to an oxide film before brazing heating are formed on a surface thereof, by brazing heating.

An electrostatic chuck includes a ceramic top plate layer made of a beryllium oxide material, a ceramic bottom plate layer made of a beryllium oxide material, a ceramic middle plate layer disposed between the ceramic top plate layer and the ceramic bottom plate layer, an electrode layer disposed between the ceramic top plate layer and the ceramic middle plate layer, and a heater layer disposed between the ceramic middle plate layer and the ceramic bottom plate layer. The electrode layer joins and hermetically seals the ceramic top plate layer to the ceramic middle plate layer, and the heater layer joins and hermetically seals the ceramic middle plate layer to the ceramic bottom plate layer.

An aluminum alloy brazing sheet is formed of a four-layer material formed of a brazing material, an intermediate material, a core material, and a brazing material. The intermediate material comprises Mg of 0.40 to 6.00 mass %, and has a total of contents of Mn, Cr, and Zr being 0.10 mass % or more. The core material comprises Mg of 0.20 to 2.00 mass % and comprises one or two or more of Mn of 1.80 mass % or less, Si of 1.05 mass % or less, Fe of 1.00 mass % or less, Cu of 1.20 mass % or less, Ti of 0.30 mass % or less, Zr of 0.30 mass % or less, and Cr of 0.30 mass % or less. Each of the core material and the intermediate material has a grain size of 20 to 300 μm.

An aluminum brazing sheet for flux-free brazing having a multilayer structure of two or more layers including at least one core material layer and one brazing material layer, wherein the brazing material layer is positioned on one or both sides of the core material layer and on an outermost surface of the brazing sheet. The brazing material layer is made of an Al—Si—Mg—X brazing material containing: in mass%, 0.05 to 2.0% of Mg, and 2.0 to 14.0% of Si, and further containing one or more of 0.01 to 0.3% of Bi, Ga, Sn, In and Pb, a total amount of Bi, Ga, Sn, In and Pb being 0.5% or less. X indicates one or more of Bi, Ga, Sn, In and Pb.

A closed impeller (1) includes an impeller main body (2), which is composed of an aluminum alloy and has blades (22) that protrude from a hub (21). A shroud (3) covers the blades. The blades and the shroud are joined together by brazed joints (4). The shroud (3) is formed from a brazing sheet (30) that comprises a core material (31), which is composed of an aluminum alloy, and a filler material layer (320), which is disposed on an outermost surface (33) of the shroud that opposes or faces the blades when the shroud is brazed to the blades.

An aluminum alloy brazing sheet for a heat exchanger includes a three-layer material in which a brazing material layer, an intermediate layer, and a core material are cladded and stacked, the intermediate layer is formed of an aluminum alloy which can include Mn, Si, Fe, and Cu, with the balance being Al and inevitable impurities, the core material is formed of an aluminum alloy which can include Si, Fe, Cu, and Mn, with the balance being Al and inevitable impurities, and the brazing material layer is formed of an aluminum alloy including Si, with the balance being Al and inevitable impurities.

An aluminum alloy brazing sheet is formed of a four-layer material formed of a brazing material, an intermediate material, a core material, and a. brazing material. The intermediate material comprises Mg of 0.40 to 6.00 mass %, and has a total of contents of Mn, Cr, and Zr being 0.10 mass % or more. The core material comprises Mg of 0.20 to 2.00 mass % and comprises one or two or more of Mn of 1.80 mass % or less, Si of 1.05 mass % or less, Fe of 1.00 mass % or less, Cu of 1.20 mass % or less, Ti of 0.30 mass % or less, Zr of 0.30 mass % or less, and Cr of 0.30 mass % or less. Each of the core material and the intermediate material has a grain size of 20 to 300 μm.

New aluminum alloy brazing sheets are disclosed. The new aluminum alloy brazing sheets may include a core, an interliner layer adjacent the core, and a braze liner adjacent the interliner layer. The interliner layer may include a first aluminum alloy having at least 0.35 wt. % Si and from 0.05 to 2.0 wt. % Mg. The braze liner may include a second aluminum alloy having 0.05 to 2.0 wt. % Mg. The first aluminum alloy and the second aluminum alloy may include an amount of magnesium sufficient to achieve T.sub.solidus(IL)≥5° C. T.sub.liquidus(BL). The new aluminum alloy brazing products may be useful, for instance, in fluxfree brazing.