Abstract: For improvement in heat radiation capability without sacrifice of affinity for a paste, a substrate used for fabrication of a thick film circuit has a multi-level structure having a foundation of an aluminum nitride and a surface film provided on the foundation, and the surface film is formed of an oxygen compound containing silicon atoms.

Abstract: A Cu-Ag alloy brazing filler material with low Ag content that exhibits excellent brazability and has a low vapor pressure is disclosed. The filler material comprises 5 to 35% by weight of Ag, 2.5 to 13% by weight of Si, with the balance being Cu and incidental impurities. The properties of the filler material can be improved further by addition of at least one element selected from the group consisting of Sn, In, Fe, Ni, Co, B and Li.

Abstract: A Cu-Ag alloy brazing material that exhibits excellent cold workability, brazability and has a low vapor pressure is disclosed. The filler material comprises more than 35 to 50% by weight of Ag, 2.2 to 6% by weight of Si, with the balance being Cu and incidental impurities. The properties of the filler material can be improved further by addition of at least one element selected from the group consisting of Sn, In, Fe, Ni, Co, B and Li.

Abstract: There is disclosed a method for manufacturing a stripe-patterned metal plate or composite material. Plural kinds of metal sheet blanks having different colors are placed one upon another to provide a layer structure. The metal sheets of the layer structure are bonded to each other directly and metallurgically in a solid state to provide a layer-structured plate. The layer-structured plate is cut in a direction along a face extending at a predetermined angle to a layer face thereof to provide at least one thin metal plate intermediate. The metal plate intermediate is inserted into a complementary hole formed through a solid package of metal. Then, the package containing the metal plate intermediate is hot rolled into a predetermined length with its width remaining substantially unchanged so that the metal plate intermediate is simultaneously extended at a predetermined reduction rate with its width remaining substantially unchanged.

Abstract: A process for welding a pair of thick copper plates which comprises welding the pair of copper plates with respective edges placed adjacent to each other on a backing support made of carbon at the adjacent edges in an atmosphere of an inert gas by melting a filler metal with the use of a direct current arc generated between the copper plates connected to the negative pole and a positive electrode with an arc voltage V (volt) and a welding current I (ampere) satisfying the conditions:V = 37 - 45 (1)vi>q (2)i.sup.2 /.sqroot.v < f (3)wherein Q and F are respectively determined from the equations:Q = Va Ia (4)F = Ib.sup.2 /.sqroot.Va (5)wherein Ia (ampere) is the minimum current at which a penetration to the underside of the copper plate is obtained and Ib (ampere) is the minimum current at which a blow hole is formed in the weld by the decomposition of the backing support at any voltage Va (volt) within the above stated range (1).