Abstract: An electric far-infrared heater has a plate-like porous metallic panel formed by an electroforming process installed in a box-like housing over an electric heating element therein. The panel is heated by the element and has its outer surface covered by a porous ceramic far-infrared emitting layer of Al.sub.2 O.sub.3, TiO.sub.2, Cr.sub.2 O.sub.3, MgO, ZrO.sub.2, SiO.sub.2 or mixtures thereof. A stream of gas supplied to the interior of the housing is heated by the element and passes through the porous panel and far-infrared layer for discharge onto the object being heated.

Abstract: A tunnel-type reflow furnace containing a preliminary heating zone and a main heating zone is disclosed. In the furnace, at least two pairs of infrared heaters are disposed on both the top and bottom of a tunnel providing a pathway for the transfer of an article to be heated, and the infrared heaters are of a gas blowing type. In a preferred embodiment, a gas-blowing nozzle that is freely adjustable in the direction of gas blowing is provided between infrared heaters on both the top and bottom of the tunnel. This furnace allows the heating profile to be easily changed in accordance with a specific use. It is also capable of efficient and uniform heating of a printed circuit board even if it carries many components at high density. As a result, the furnace ensures reliable soldering of the circuit board.

Abstract: An improved semiconductor element-manufacturing method which saves a semiconductor wafer from the occurrence of cracks or damage during the manufacture of a semiconductor element and enables solder layers to be deposited without irregularities in the thickness. The method starts with the step of forming a first metal layer acting as an ohmic electrode on each side of the element regions of a semiconductor wafer in which a plurality of active elements are formed or on the whole surface of each side of the semiconductor wafer. Then a second metal layer which has an anticorrosive property and acts as a brazing material when the semiconductor element is mounted between a pair of electrodes is selectively deposited by electroplating on each of the element areas in the first metal layers.

Abstract: Disclosed is a bismuth-tin-indium alloy consisting essentially of 53 to 76 weight % of bismuth, 22 to 35 weight % of tin and 2 to 12 weight % of indium. This alloy has excellent sealing property and oxidation resistance, and is suitable particularly to the use as a seal material for a rotating plug of a nuclear reactor.

Abstract: Disclosed is a bismuth-tin-indium-lead alloy consisting essentially of 28 to 72 weight % of bismuth, 25 to 52 weight % of tin, 2 to 12 weight % of indium and 1 to 8 weight % of lead. This alloy has excellent sealing property and oxidation resistance, and is suitable particularly to the use as a seal material for a rotating plug of a nuclear reactor.