Abstract: An assembly consisting of at least one seal layer and a solid polymer ion exchange layer wherein the seal layer covers essentially only the region of the ion exchange layer which is to be sealed. The seal layer is made of porous polytetrafluoroethylene film having one surface coated and partially impregnated with a solid polymer ion exchange material. The seal layer provides support and masking functions for the solid polymer ion exchange layer during intermediate manufacturing steps, and reinforcement and effective sealing when assembled in an electrochemical apparatus.

Abstract: The present invention relates to a plating bath of the hydrazine type for electroless plating on the surface of a plated substance with iridium. The first plating bath is an electroless plating bath of iridium which contains a hydrazine complex of iridium and has pH of 1-7. The second plating bath is an electroless plating bath of iridium which contains hydrazine hydrate and/or hydrazinium salt, and iridium halide and/or halogenoiridate in the molar ratio of 1-1.0 and has pH of lower than 3. The plating bath of this invention is used, for example, for producing of a junction of a cation exchange membrane and iridium, which is used for a water electrolytic cell of the macromolecule solid electrolyte type.

Abstract: A process for electroless gold plating using plating solution comprizing cyanoaurate, alkaline cyanide, reducing agent, alkaline hydroxide, crystal condition controlling agent and stabilizer characterized in that an aldehyde or a ketone compound is added together with replenished gold salt, and hydrogen peroxide is also added, if necessary.

Abstract: An electroless palladium plating composition which comprises (1) 0.001-0.1 mol/l of a palladium compound, (2) 0.01-1 mol/l of a hypophosphite compound, (3) 0.01-5 mol/l of at least one member selected from the group consisting of ammonia and alkylamine compounds, (4) 0.01-20 mg/l of high-molecular weight polyethyleneimine having molecular weight of 300 to 100000 and (5) 0.01-10 g/l of an aliphatic alkyenylamine, and which is used at a pH in the range of 5-10.

Abstract: A moisture-sensing hygrometric element is provided comprising an electrolytic moisture-sensing mechanism integrally formed on the surface of a porous substrate, the porous substrate being resistant to oxidation and reduction and resistant to acids, wherein the moisture-sensing mechanism comprises a pair of platinum group metal electrodes constituting an anode and a cathode and having a fluororesin-type cation exchange resin membrane layer thereover. The porous substrate may be porous ceramic or a porous fluororesin such as expanded polytetrafluoroethylene. The hygrometric element may have an additional covering layer thereover of porous, expanded polytetrafluoroethylene. Also provided is a method for manufacturing the moisture-sensing hygrometric element.

Abstract: A moisture-sensitive element is produced by applying an ultraviolet-setting alkali-elution type resist ink on a prescribed part of a cation-exchange membrane, curing and drying the applied layer of the resist ink, chemically plating the cation-exchange membrane thereby forming electrode layers thereon, and thereafter removing the resist ink from the cation-exchange membrane.

Abstract: A positive electrode suitable for the electrolysis of water is produced by immersing a nickel electrode in an aqueous solution containing a nickel salt, a rhodium salt, and an alkyl amine borane.

Abstract: Disclosed is a method for the manufacture of an ion-exchange membrane--catalytic metal composite, which comprises treating the surface of an ion-exchange membrane with a low-temperature gas plasma to thereby form micropores on the membrane surface, and with or without subjecting the ion-exchange membrane to a hydrothermal treatment at 100.degree.-200.degree. C., then attaching a catalytic metal onto the ion-exchange membrane.

Abstract: A chemical-resistant diaphragm composed of a fluorine-containing polymer and potassium titanate and a method for the manufacture of said diaphragm by the steps of adding titanium oxide or titanic acid to a fluorine-containing polymer and heating the resultant mixture in the presence of potassium hydroxide.

Abstract: Removal of silver and reduction of COD value in used or exhausted photographic fixing solution are effectively conducted by electrolysis of reversing repeatedly polarity of positive and negative electrodes.

Abstract: An electrode having a lead dioxide coat electrodeposited on a porous ceramic substrate is manufactured by soaking a porous ceramic substrate in an aqueous lead (II) salt solution and thereby allowing lead oxide to be deposited in the porous surface layer and on the surface of the substrate thereafter soaking said porous ceramic substrate in a persulfate solution to cause oxidation of the lead oxide so deposited therein and thereon and effecting electrolysis in an aqueous lead (II) salt solution by using said lead dioxide-coated substrate as the anode and the aqueous solution as the electrolyte and thereby causing lead dioxide to the additionally electrodeposited on said lead dioxide coat.The electrode manufactured as described above excels in corrosion-resisting property and therefore proves quite advantageous as an electrode for use in the electrolysis of aqueous solutions.

Abstract: Single crystals of .beta.-PbO.sub.2 are formed when an intermediate oxide of lead represented by the generic formula, PbO.sub.x wherein x denotes a value falling in the range of 1.4 to 1.7, is heated in an aqueous alkali hydroxide solution under a pressure exerted by use of oxygen or an oxygen-containing gas. The single crystals are in the shape of slender rods, have a black color and have a metallic gloss.