Showing papers on "Sodium hypophosphite published in 1967"

Nickel coated flake pigments and methods for their preparation

Abstract: 1,272,011. Nacreous pigments. E. I. DU PONT DE NEMOURS & CO. 20 May, 1969 No. 25710/69. Heading C4A. [Also in. Division C7] Pigments having a metallic sheen comprise glass or mica flakes coated with metallic nickel and further coated with nickel oxide or hydrous titania. The pigments are obtained by pretreating the glass or mica flakes with stannous and palladium chlorides, depositing a coating of nickel thereon by treating the flakes with a nickel -salt solution containing sodium hypophosphite reducing agent, at a pH below 7 and a temperature of at least 55‹ C., and then either subjecting the coated flakes to a controlled oxidation to give a nickel oxide surface coating, or depositing a layer of hydrous titania by hydrolysis of a titanium salt, and heating the coated pigment to 200-350‹ C.

Method of chemical nickeling and cadmium chemical plating of metallic and nonmetallic substrates

Abstract: A METHOD OF APPLYING SMOOTH NICKEL OR CADIUM COATINGS TO METALLIC OR NONMETALLIC (E.G., FABRIC) SUBSTRATES IN WHICH THE DEGREASED AND DEOXIDIZED SUBSTRATE SURFACE IS TREATED WITH AN AQUEOUS SOLUTION OF A CADMIUM OR NICKEL SALT (E.G., THE METAL SULFATE OR CHLORIDE) AND SODIUM HYPOPHOSPHITE WHEREBY, AFTER THE ADDITION TO THE CHEMICAL-PLATING BATH OF AN ORGANIC ACID (PREFERABLY FORMIC ACID), THE BATH IS RAISED FROM ITS PH OF ABOUT 2 WITH A BASIC COMPOUND (E.G., NH4OH) TO APPROXIMATE NEUTRALITY (PH OF ABOUT 6.5 TO 9) AND IS STABILIZED THEREAFTER BY A COMPLEX FORMER OF THE ETHYLENEDIAMINETETRAACETIC ACID (EDTA FAMILY).

Improvements in or relating to cutting instruments

Abstract: Electroless plating High carbon steel strip is coated with nickel-phosphorus after the following cleaning operations; degreasing is trichlorethylene, cathodic cleaning in an aqueous alkali cleaner, the solids content of which comprises 85% trisodium phosphate, 10% sodium metasilicate and 5% wetting agent; washing and dipping in 10% aqueous hydro-chloric acid solution. The strip is immersed in a plating solution comprising:- .nickel chloride.30 gm./litre .sodium hypophosphite.10 gm./litre .sodium acetate.5 gm./litre .sodium citrate.21.75 gm./litre .sodium thiosulphate.0.006 gm./litre The solution is maintained at 90 DEG -95 DEG C. and the nickel content of the solution kept approximately constant by adding nickel chloride, sodium hypophosphite and sodium acetate. A deposit 0.002" thick is obtained after 5 hours immersion. Electrolytic plating Steel strip is cleaned as in the previous example, except that ultrasonic degreasing in perchloroethylene is used. The strip is immersed in an aqueous plating solution comprising:- .nickel sulphate.160 mg./litre .nickel chloride.46 gm./litre .phosphoric acid.50 gm./litre .phosphorous acid.22 gm./litre The solution is maintained at 70 DEG -80 DEG C, the anodes being of nickel and the current density being 20-40 amps./dm2. In less than 1 hour a deposit 0.002" thick is obtained. A coating of cobalt-phosphorus is obtained in an aqueous plating solution comprising:- .cobalt chloride.180 gm./litre .phosphoric acid.50 gm./litre .phosphorous acid.40 gm./litre The strip is connected as the cathode and cobalt anodes are used. The solution is maintained at 70 DEG C., the current density is 30 amps./dm2 and in less than an hour a deposit 0.002" thick is obtained.

Room temperature electroless nickel plating bath

Abstract: A PROCESS FOR DEPOSITING NICKEL ONTO A SUBSTRATE FROM A ROOM TEMPERATURE ELECTROLESS PLATING BATH; THE BATH INITIALLY INCLUDES (I) A NICKEL SALT, (II) SODIUM HYPOPHOSPHITE, (III) SODIUM PYROPHOSPHATE, AND (IV) AMMONIUM HYDROXIDE. THE CONCENTRATION OF AMMONIUM HYDROXIDE IS CHOSEN SO AS TO ADJUST THE PH OF THE BATH TO AN INITIAL VALUE (BETWEEN 9.0 AND 11.5) CORRESPONDING TO THE DESIRED PLATING RATE. A STRONG BASE SUCH AS SODIUM HYDROXIDE IS THEN ADDED TO INCREASE THE PH OF THE BATH ABOVE THE INITIAL VALUE WITHOUT SUBSTANTIALLY AFFECTING THE PLATING RATE. IN USE, THE PH OF THE BATH DECREASES, BUT THE PLATING RATE REMAINS RELATIVELY UNAFFECTED SO LONG AS THE PH DOES NOT DROP BELOW THE INITIAL VALUE SET BY THE AMMONIUM HYDROXIDE. THIS PERMITS WIDER TOLERANCES IN PH CONTROL OF THE BATH AND ALLEVIATES THE NEED FOR ADDING AN ACCURATELY CONTROLLED AMOUNT OF HYDROXYL ION WHEN THE BATH IS REGENERATED.

Improvements in plating conducting areas on insulating surfaces

Abstract: In order to electroplate or galvanically plate isolated conductive areas 3 of a printed circuit formed by photo-etching a copper-clad phenolformaldehyde laminate 1, the areas 3 are interconnected by electroless deposition. After the plating step, the bridges are removed using a solvent for the resist. Alternatively, the areas to be made conductive and the resist bridges are simultaneously first electroless-coated, then plated. In an example, the bridges are formed of shellac in butyl alcohol with glycerol, a catalyst for the electroless step, comprising palladium chloride dissolved in conc. HCl, being added. Nickel is electroless-deposited in a bath comprising Nickel acetate (21 g/l), Sodium hypophosphite (24 g/l), Sodium lactate (20 g/l), acetic acid (10 ml/l); then a layer of gold may be added in an electroless-plating bath comprising Ammonium chloride (75 g/l), Sodium nitrate (50 g/l), Sodium hypophosphite (10 g/l), Potassium gold cyanide (2 g/l). The conductive areas and bridges are then electroplated with gold, after which the plated shellac bridges are removed by rubbing or brushing with methylated spirit. In another example, the bridges are formed from gum sandarac dissolved in methylated spirit, the palladium chloride catalyst solution being painted on subsequently. Ethyl alcohol is used to remove the bridges. Other resist gums mentioned include copal and kauri, and cobalt may replace nickel in the first electroless-plating step.

Improvements relating to plating processes

Abstract: In an electroless process for depositing e.g. Ni-P, Co-P or Cu on a substrate of e.g. glass ceramic, N, Mo, Si or Ge in which the substrate is pretreated with a solution of palladium chloride, the substrate is first etched in a solution of hydrofluoric acid in an organic solvent e.g. acetone. The etching may take place simultaneously with the palladium chloride treatment. In an example a plating solution comprises (g./1.) sodium pyrophosphate 50, Nickel sulphate 25, sodium hypophosphite 25, and ammonium hydroxide to bring the pH to 10 to 11.

Determination of aluminium in steel

Abstract: Aluminium in steel has been gravimetrically determined as phosphate after precipitation at a controlled pH of 3.7–3.9. Iron has been complexed with thioglycollic acid and ammonium thiocyanate. Titanium and zirconium, if present, are removed from the acidic solution with sodium hypophosphite and bromine water. Copper group elements, if present, are removed by passing hydrogen sulphide through the solution. Chromium, vanadium, manganese, nickel and cobalt do not interfere.