Abstract: Disclosed is a method of treating an electroless nickel plating bath mainly containing a water-soluble nickel salt, a complexing agent for complexing the nickel salt, and sodium hypophosphite as a reducing agent for reducing the nickel salt, including the steps of:repeatedly regenerating and reusing the electroless nickel plating bath in which a phosphite is accumulated by adding nickel sulfate to the plating bath to produce and precipitate nickel phosphite and separating the nickel phosphite from the plating bath; and adding sulfuric acid or a mixture of sulfuric acid and sodium sulfate to the nickel phosphite separated from the plating bath to convert the nickel phosphite into nickel sulfate and phosphorous acid or NaH.sub.2 PO.sub.3, and recovering the nickel sulfate.

Abstract: To an electroless gold plating bath comprising a water-soluble gold compound, a complexing agent, and a reducing agent is added a small amount of polyvinyl pyrrodidone. The bath allows a satisfactory gold plating film to be formed on metal portions on a non-conductive substrate without plating spread.

Abstract: Valuable substances are recovered from a spent electroless nickel plating solution containing a water-soluble nickel salt, organic complexing agent, hypophosphite, phosphite, and alkali metal ion by adding oxalic acid to the plating solution for causing a nickel ion to precipitate as nickel oxalate for removal and recovery; optionally adding a sulfide to the plating solution for causing a heavy metal ion to precipitate as a heavy metal sulfide for removal; adding a mineral acid and calcium oxide, calcium hydroxide, calcium carbonate, calcium sulfate, calcium chloride or a calcium salt of organic acid to the plating solution from which the nickel ion has been removed; firing solids of the solution in air for converting the alkali metal ion into an alkali metal salt of mineral acid, converting phosphorus into hydroxyapatite, and pyrolyzing off the organic material; and pouring a solid mixture of the alkali metal salt of mineral acid and hydroxyapatite into water for dissolving the alkali metal salt of mineral a

Abstract: A workpiece is buffed to a scratch-free mirror finish by contacting the workpiece against a buff while rotating the buff at about 100 to 1,000 rpm and feeding a buffing compound to the buff. The buffing compound is a slurry containing 3 to 20 wt % of abrasive grains with a mean grain size of up to 2 .mu.m in an aqueous fatty acid soap solution.

Abstract: Metal is deposited on a three-dimensional network plastic substrate having internal open cells by a gas phase plating technique to form a metal layer covering all three-dimensional network lattice surface to form a support. An active material is carried on the support to form an electrode. The electrode is improved in active material-support adhesion, allows the amounts of conductive agent and binder to be reduced, and provides a cell with improved performance. It is especially useful in a secondary lithium cell.

Abstract: A process and apparatus for monitoring the etching ability of an etchant by accurately measuring the etching rate with a relatively simple arrangement. A process and apparatus for monitoring the etching rate is determined by channeling the etchant from an etching tank to a reaction column, subjecting a specimen of the same material as a metal part to be etched in practice to etching with the etchant in the reaction column, collecting hydrogen gas generated during etching of the specimen, measuring the time taken until a predetermined quantity of hydrogen gas is generated, and computing the etching rate from the measured time.

Abstract: To a neutral electroless gold plating bath comprising a gold sulfite, a sulfite, and a reducing agent, there are added an organic phosphonic acid or a salt thereof and an optional stabilizer in the form of a non-ionic surfactant or non-ionic polymer. A gold plating film having an aesthetic lemon yellow color tone and susceptible to bonding deposits on an article from the bath without attacking the base material of the article and without plating spread.

Abstract: An electroless copper plating bath comprises a water soluble copper salt, a complexing agent, and a reducing agent consisting of phosphorous acid or a phosphite. As compared with conventional acidic bath using hypophosphorous acid, the bath is less expensive while depositing a uniform copper film at equivalent efficiency.

Abstract: In electroless or electric tin, lead or tin-lead alloy plating solution which may contain copper, the concentration of a metal ion component selected from divalent tin ion, lead ion, and copper ion is quantitatively determined by taking a sample from the solution, adding a chemical agent, for example, an oxidizing agent to the sample, thereby causing the selected metal ion to develop its color, measuring the absorbance of the sample due to the metal ion by colorimetry, and determining the concentration from the absorbance. A choice of chemical agent depends on a particular metal ion on analysis. When the solution contains more than one metal ion, correction is made by repeating the process using another chemical agent.

Abstract: A tin or tin-lead alloy electroless plating bath comprising (A) a stannous salt or a mixture of a stannous salt and a lead salt, (B) an acid, (C) thiourea or a thiourea derivative, and (D) a reducing agent is improved by adding (E) a nonionic surfactant and optionally, (F) a cationic surfactant, a nitrogenous heterocyclic compound or a derivative thereof, or alternatively by adding (G) an ammonium or quaternary ammonium ion. From the bath, uniform films of fine grains will chemically deposit on fine pitch printed wiring boards intended for SMT.

Abstract: A composite deposit in which insoluble particles are co-deposited and dispersed in a metal matrix is formed on an article by dipping the article in a metal plating solution having insoluble particles dispersed therein and effecting an electroplating or chemical plating process. By adjusting the specific surface area of insoluble particles to be dispersed in the metal plating solution, the amount of insoluble particles co-deposited in the composite deposit can be controlled. Better results are obtained with insoluble particles having a specific surface area of 10 m.sup.2 /g or less.

Abstract: For replenishing a metal ion to a plating bath, a soluble electrode of the same type of metal as in the bath and a counter electrode of a metal material having a nobler standard electrode potential than the soluble electrode are immersed in the bath. Electricity is conducted between the soluble electrode and the counter electrode, thereby dissolving the soluble electrode to replenish an ion of the metal of the soluble electrode to the bath. The potential of the counter electrode is measured using a reference electrode of the same metal as the soluble electrode. The quantity of electricity is controlled such that the measured potential may not be negative with respect to the reference electrode, thereby preventing deposition of the dissolving metal ion on the counter electrode while ensuring a high rate of metal ion dissolution.

Abstract: A composite film consisting of particles of fibers dispersed in a metal matrix and formed by electroless deposition can be improved in appearance and particle or fiber content by adding a water-soluble amine or ammonium salt to the electroless plating bath. Preferably the bath contains a water-soluble nickel or cobalt salt, a hypophosphite reducing agent, a chelating agent for chelating the nickel or cobalt ion, a surface active agent, water-insoluble particles or fibers typically of polytetrafluoroethylene, and the water-soluble amine or ammonium salt.

Abstract: A composite plating apparatus includes a plating tank for receiving therein a composite plating solution containing water-insoluble particles or fibers and a reservoir disposed adjacent the plating tank through an overflow weir, preferably in a common housing, the plating solution flowing into the reservoir in an overflow manner. A pump is disposed within the reservoir having a suction port for drawing the solution in the reservoir and a discharge port for pumping the solution. A conduit connected to the pump discharge port extends therefrom over the bottom of the plating tank through the overflow weir and includes a plurality of orifices. The plating solution is circulated by causing the solution to flow over the weir from the plating tank to the reservoir, pumping the solution to the conduit, and injecting the solution into the tank through the orifices to uniformly agitate the solution.

Abstract: The concentration of a plating solution in which a workpiece is plated is automatically controlled within a permissible range by replenishing a consumable ingredient to the plating solution in an amount corresponding to the amount of consumption estimated from the surface area of the workpiece for a given plating solution composition under given plating conditions. By measuring the concentration of the consumable ingredient in the plating solution, the replenishment of consumable ingredient is interrupted for a predetermined time or the amount of the consumable ingredient replenished is reduced when the measured concentration is above the permissible range, or the amount of consumable ingredient replenished is increased or a necessary amount of the consumable ingredient is additionally supplied to the plating solution separately from the normal replenishment of consumable ingredient when the measured concentration is below the permissible range.

Abstract: A bath for electrodepositing tin, lead or an alloy thereof, containing a tin and/or lead ion and a sulfate ion becomes stable at pH 1 or higher when a condensed phosphate ion is added thereto. The bath is effective for depositing tin-lead alloy films on sealing glass-metal integrated articles.

Abstract: The concentration of a plating solution in which a workpiece is plated is automatically controlled within a permissible range of replenishing a consumable ingredient to the plating solution in an amount corresponding to the amount of consumption estimated from the surface area of the workpiece for a given plating solution composition under given plating conditions. By measuring the concentration of the consumable ingredient in the plating solution, the replenishment of consumable ingredient is interrupted for a predetermined time or the amount of the consumable ingredient replenished is reduced when the measured concentration is above the permissible range, or the amount of consumable ingredient replenished is increased or a necessary amount of the consumable ingredient is additionally supplied to the plating solution separately from the normal replenishment of consumable ingredient when the measured concentration is below the permissible range.

Abstract: An entrance chamber is provided adjacent a plating chamber at a substantially same level as the plating chamber. A carrier is provided for supporting a jig for hanging a workpiece and for conveying the jig between the entrance chamber and the plating chamber. A conveying device is provided in the plating chamber for conveying the jig between the carrier and a plating tank in the plating chamber for performing the plating of the workpiece.

Abstract: A rocket engine combustion chamber is defined by a generally cylindrical member comprising a metal matrix and heat insulating particles wherein the particles are distributed in the matrix such that the amount of particles gradually decreases in a radial direction from the inner surface to the outer surface of the member. Such a member is manufactured by controlled composite electroplating.

Abstract: A composition comprising succinimide and/or phthalimide and an alkali metal hydroxide is effective for electrolytically stripping silver. Unnecessary silver coating portions can be electrolytically stripped from a silver-plated article by immersing the article in a solution of the stripping composition, and applying voltage to effect electrolytic stripping.