Abstract: A copper foil for printed circuits including a thermal oxidation-resistant treated layer (e.g., Zn--Ni or Zn--Co alloy plating) formed on the shiny side of the foil and a Cr-base anticorrosive treated layer (e.g., chromate film, mixed film of chromium oxide and zinc and/or zinc oxide, or both) formed further thereon, characterized in that a copper plating layer or an etched surface is provided before forming the thermal oxidation resistant treated layer. The copper plating or etching permits the shiny side to be completely covered with fresh copper or purified to overcome any ununiformity of the chemical activity and/or any lack of smoothness of the entire surface of the shiny side. The evenness of the freshly formed copper surface enhances the homogeneity and completeness of the thermal oxidation-resistant plated layer to be formed subsequently by thermal oxidation resistance treatment, rendering it possible to take the full advantage of the thermal oxidation-resistant treated layer.

Abstract: A method is provided for producing high purity electrolytic copper useful, for example, to make a copper wire for use in sound or image reproducing systems, such as audio, video and television systems, etc. The copper wire consists of high purity copper in which silver and sulfur contents are both not more than 0.5 ppm and preferably has a crystal grain size not less than 0.02 mm and is unidirectionally solidified or is a single crystal. Such a copper wire is manufactured by continuously casting electrodeposited copper which has been obtained by refining by re-electrolysis of electrolytic copper, using a specially arranged casting apparatus having a mold projecting to an electrolytic bath.

Abstract: The present invention relates to a copper wire for use in sound or image reproducing systems, such as audio, video and television systems, etc., and a method for manufacturing the same. The copper wire consists of high purity copper in which silver and sulfur contents are both not more than 0.5 ppm and preferably has a crystal grain size not less than 0.02 mm and is unidirectionally solidified or single crystallized. Such a copper wire is manufactured by continuously casting electrodeposited copper which has been obtained by refining by re-electrolysis of electrolytic copper, using a specially arranged casting apparatus having a mold projecting to an electrolytic bath.

Abstract: Composite powder coated with a noble metal is produced by adding a powder of a metal or alloy baser than the noble metal to a powder of a metallic sulfide, carbon, activated charcoal, metallic carbide, or metallic oxide, and then adding to the resulting mixture a solution containing the noble metal with stirring. The particles of the composite powder are coated with the noble metal that results from a cementation reaction.

Abstract: A multilayer-coated composite powder is produced by a first step of treating a core powder to be coated with first metallic ions and a metallic powder for reducing the first ions and thereby forming a single-layer coated powder, and a second step of treating the single-layer-coated powder with either only second metallic ions other than the first metallic ions or the second ions in the presence of a metallic powder for reducing the second ions. Where necessary, the second step is repeated the number of times required for forming a predetermined number of coating layers.

Abstract: A double-metal-coated metal sulfide powder comprises particles of a metal sulfide, a layer of a platinum group metal coating formed thereon, and an outer coating layer of a metal or alloy which contains at least one of iron, copper, nickel, and cobalt. The powder is obtained by forming a platinum group metal layer on metal sulfide particles by thermal decomposition of a plating composition which includes at least one platinum-metal compound containing a radical selected from the class consisting of NO, NO.sub.2, NO.sub.3, and NOCl and then forming a layer of at least one metal selected from the group consisting of iron, copper, nickel, and cobalt by the cementation reaction.

Abstract: A method for plating a powder with a metal by substitution, which comprises adding a crystalline powder of a metal chloride hydrate after and/or during mixing a powder to be plated and a reducing metal powder, and after the initiation of the reaction, adding water and/or hydrochloric acid.

Abstract: A process for granulating metal sulfide powders comprises the steps of adding a solution of thermosetting resin in a volatile organic solvent, as a binder, to a metal sulfide powder as the starting material, forming the mixture thus obtained into granules by a granulator, drying the granulation product, sieving the dried product for classification and recovering the granules within desired limits of particle size, recycling the fines after the sieve classification, with the addition of only the volatile organic solvent, as the material, and heating the granules within the desired limits of particle size for curing. Coarse particles separated out by the sieve classification are pulverized and recycled as the material, with the addition of only the volatile organic solvent.

Abstract: A method for preparing a raw board for use in printed circuits comprising the steps of first electroplating a foil or sheet of synthesized resins in an electrolytic bath containing copper sulfate, sulfuric acid, chlorine ion and a surface glazing agent including thiourea, and secondly electroplating the foil or sheet completed the above step in a conventional electrolytic bath containing copper sulfate and sulfuric acid. Also, an apparatus therefor is disclosed.

Abstract: Metal sulfide powder coated with copper is produced by mixing powder of a metal and/or an alloy baser than copper with powder of a metal sulfide, and then adding an acidic solution containing copper ions to the resulting mixture with stirring. The metal sulfide particles are coated with metallic copper that results from a cementation reaction. Where the metal sulfide powder contains too coarse or fine particles, it is ground, granulated, and sized before the mixing.