Showing papers on "Sodium hypophosphite published in 1987"

Green Electrochromism in the System of p-Cyanophenylviologen and Potassium Ferrocyanide

Abstract: A high-performance green-electrochromic display has been developed in a system of p-cyanophenylviologen (p-CV) and potassium ferrocyanide in the presence of sodium hypophosphite and potassium chloride. The main difficulty was in the fact that p-CV reacts with potassium ferrocyanide to form a scale-like green precipitate even in the absence of any applied voltage when the concentration of p-CV exeeds only 0.001 M. At this concentration, only a poor write-erase contrast ratio can be obtained. The addition of an excess of potassium chloride, however, dissolves the precipitate, which enabled a concentration as high as 0.035 M to be attained and hence a high contrast ratio. Sodium hypophosphite facilitates the erasing of the reduced p-CV ("green") and thus contributes to a long working lifetime. The electrochromic characteristics obtained are as follows: driving voltage of 0.4–0.9 V, contrast ratio of 50:1 and write-erase cycle of about 3 × 107.

Process for preparing phosphonous acids

Abstract: A process is provided for preparing phosphonous acids of the structure wherein R 1 is lower alkyl or arylalkyl ##STR1## which are useful in preparing phosphinic and phosphonic acid ACE inhibitors, which process includes the steps of treating an olefin of the structure R 1 --CH═CH 2 wherein R 2 is lower alkyl or arylalkyl with a phosphorus-containing reagent such as sodium hypophosphite or hypophosphorous acid in the presence of an organic alcohol solvent such as ethanol or methanol, and a radical initiator such as azobisisobutyronitrile, under acidic conditions, preferably at the reflux temperature of the organic solvent, to form the phosphonous acid without forming the alkyl ester.

Production of metallic fine powder

Abstract: PURPOSE: To produce metallic fine powder having the desired grain size under high yield by further adding metallic ion, reducing agent and pH conditioner after executing reduction reaction by adding reaction initiator to mixed water solution of the metallic ion, reducing agent and complexing agent. CONSTITUTION: The complexing agent water solution (citric acid, etc., about 0.01W1mol./l concn.) adjusted to the prescribed pH, is heated to ≥about 50°C and the metallic salt water solution (Ni, copper, etc.,) and the reducing agent water solution (sodium hypophosphite, etc.,) are added at suitable quantity and further a little quantity of the reaction initiator is added to execute reduction reaction of the metal. At the time of completing the reaction, further as the same way as the above, the metallic salt water solution and the reducing agent water solution are dripped at the fixed dripping speed to continue the reaction and pH in the solution during reaction is adjusted. When the dripping and the reaction complete, the solution is filtrated and after repulping-washing the filtrated residue, it is dried. By this method, the metallic powder having the desirable grain size and extremely stable quality with a little impurity is produced under good productivity. COPYRIGHT: (C)1988,JPO&Japio

Corrosion resistant nickel-zinc-phosphorus coating and method of electroplating said coating

Abstract: Corrosion resistant electrodeposit comprising a solid solution of phosphorus and nickel supersaturated with zinc. The electrodeposit is formed from an electrolyte containing nickel chloride, zinc chloride and sodium hypophosphite having a nickel ion to zinc ion molar ratio between about 7 and about 12 and deposited at current densities greater than about 0.6 A/cm 2 .

Gold-nickel alloy plating solution and plating method

Abstract: PURPOSE:To form Au-Ni alloy plating having an Au content within a wide range by adjusting the pH of an acidic Au-Ni alloy plating soln. and the concns. of Au and Ni in the plating soln. contg. potassium gold cyanide and nickel acetate as principal components and further contg. a pH buffer, a stabilizer and a brightener. CONSTITUTION:Electroplating is carried out with an acidic Au-Ni alloy electroplating soln. of 3-6.5pH contg. 0.1-30g/l (expressed in terms of Au) potassium gold cyanide and 0.1-50g/l (expressed in terms of Ni) nickel acetate in 1/5-1/2 ratio of Au/Ni at 15-80 deg.C and 0.1-10A/dm cathode current density. The plating soln. further contains 10-300g/l alkali acetate such as sodium acetate or potassium acetate as a pH buffer, the proper amount of an alkali hypophosphite such as sodium hypophosphite as a brightener and the proper amount of sodium citrate or the like as a stabilizer. Au-Ni alloy plating having an Au content within a wide range is obtd. by adjusting the pH of the plating soln. and the concns. of Au and Ni in the plating soln.

Method for plating structural member of electrolytic cell

Abstract: PURPOSE:To simply and easily form nickel layers of a uniform thickness by electroless plating on the stainless steel parts of the structural members of an electrolytic cell even when the shapes of the parts are complex, by treating the parts with an acid to activate the surfaces and by carrying out direct electroless nickel plating. CONSTITUTION:The stainless steel parts of the structural members of an electrolytic cell such as the cathode chamber and the base material of the cathode are pretreated by degreasing and blasting. The pretreated parts are treated with an acid such as hydrochloric acid or oxalic acid at about 30-90 deg.C for about 10min-3hr to activate the surfaces. The activated surfaces are directly subjected to electroless nickel plating without carrying out striking or washing. The nickel plating is carried out at about 80-100 deg.C with a plating bath contg. a nickel salt such as nickel chloride, a reducing agent such as sodium hypophosphite, a complexing agent and a pH buffer or further contg. a dispersant such as TiO2. Nickel layers of about 5-200mum thickness are preferably formed by the nickel plating.

Electroless tinning bath

Abstract: PURPOSE:To weaken an attack on copper-based metals, to improve the adhesion of a film formed by tinning and to avoid adverse effects on electronic parts, etc., by using org sulfonic acid and the bivalent tin salt thereof without using mineral acid and by adding sodium hypophosphite and thiourea. CONSTITUTION:An electroless tinning bath is prepd. by using org. sulfonic acid selected among alkanesulfonic acid, alkanolsulfonic acid and arom. sulfonic acid, the bivalent tin salt thereof, sodium hypophosphite and thiourea as essential components and by further adding additives as required. By electroless tinning with the tinning bath, a practically effective tin film can be obtd. The tinning bath hardly attacks copper or copper alloy and can avoid adverse effects such as corrosion and breaking of wiring circuit. A pinhole-free uniform smooth tin film having superior adhesion is formed at a high tinning rate.

Production of composite type magnetic head

Abstract: PURPOSE:To permit the use of Mn-Zn ferrite as a head core material and to improve productivity without generating magnetic deterioration by using a composite film formed by subjecting an Ni alloy to electroless plating then to low-temp heating CONSTITUTION:After a glass substrate is heated to 94 degC, the substrate is immersed into an aq soln consisting of sodium hypophosphite, nickel sulfate and caustic soda at 94 degC so that electroless plating is executed at 04mum deposition rate The compsn of the Ni-P alloy to be plated in this stage is changed by changing the compsn of the plating bath The substrate is thereafter heated at 270-330 degC to obtain the composite film As a result, the Ni-P alloy of 5-8% P concn and 280-320 degC heating conditions enters the range of 700-1,500G Bs and <=50 Oe Hc as the conditions for the composite film and is made usable for the composite type magnetic head

Amorphous Fe-Cr-P electroplating bath

Abstract: A bath for the electrodeposition of corrosion-resistant, amorphous, Fe-Cr-P coatings comprising chromium sulfate, ferric ammonium sulfate, sodium hypophosphite, citrate ion, citric acid, boric acid and sodium, potassium, magnesium or ammonium sulfate to increase the conductivity of the bath.

Magnetic storage body

Abstract: PURPOSE:To improve the squareness ratio among the magnetic characteristics and the SN ratio among the recording and reproducing characteristics by combining a plated magnetic film having small coercive force and a favorable squareness ratio with a plated magnetic film having physical properties desirable for a magnetic storage body CONSTITUTION:A plated film of 100Angstrom thickness is formed on Ni-P film with a plating bath 1 of 90pH at 60 degC The bath 1 gives small coercive force and a favorable squareness ratio and contains 008mol/l cobalt sulfate, 002mol/l nickel sulfate, 02mol/l sodium hypophosphite, 02mol/l sodium tartrate and 02mol/ lboric acid A plated film of 700Angstrom thickness is then formed on said plated film with a plating bath 2 of 90pH at 80 degC The bath 2 contains 008mol/l cobalt sulfate, 002mol/l nickel sulfate, 07mol/l sodium hypophosphite, 02mol/l sodium tartrate, 02mol/l boric acid and 02mol/l ammonium sulfate Solid lines in the figure relate to plated films formed with the plating bath 1 In case of 100Angstrom thickness, the film has 300Oe coercive force (Hc), so a loop is rapidly closed In case of 800Angstrom thickness, considerably improved 640 Oe Hc and 085 squareness ratio are attained

Method for electroforming amorphous cr alloy at high speed

Abstract: PURPOSE:To electroform amorphous Cr alloy foil having extremely high corrosion resistance at a high speed by putting a substrate of an easily strippable material in an aqueous soln. type bath contg. a tervalent chromium salt and a salt of an oxyacid of phosphorus as essential components and by supplying a pulsating current under specified conditions to deposit an amorphous Cr alloy on the substrate. CONSTITUTION:An aqueous soln. type bath contg. a tervalent chromium salt such as CrCl.6H2O and an oxyacid of phosphorus or a salt thereof such as phosphoric acid or sodium hypophosphite as essential components is prepd. A substrate of an easily passivatable material such as stainless steel, an electrically conductive org. resin or an org. resin coated with an electrically conductive or acid-soluble metallic material is put in the bath. A pulsating current ip having a pulse cycle of 0.01-100ms on-off time is then supplied at >1- current density to deposit an amorphous Cr alloy on the substrate. This amorphous Cr alloy having high corrosion resistance is obtd. by stripping from the substrate or the dissolution of the substrate.

Manufacture of sintered magnetic alloy by means of plating treatment

Abstract: PURPOSE:To extremely easily manufacture a uniform alloy, by subjecting a magnetic powder consisting of iron, Ni, and Co to grain-size regulation and then to electroless plating in a plating bath consisting of nickel sulfate, hypophos phite, etc, and by applying compacting and sintering to the above plated mag netic powder CONSTITUTION:The magnetic powder consisting of iron, Ni, and Co is subjected to grain-size regulation and then to electroless plating in an electroless plating bath consisting of nickel sulfate, sodium hypophosphite, sodium succinate, sodium malate, etc, so that a plating layer of the prescribed thickness is provided to the whole surface of the powder The resulting magnetic powder having a plating layer is compacted into the prescribed shape, and the green compact is sintered In this way, alloying diffusion can be sufficiently carried out because an Ni-P alloy is uniformly arranged all over the sintered magnetic alloy and further the contact area between the plating layer and the magnetic powder is increased, so that uniform sintered magnetic alloy can be manufactured extremely easily

Electrolytic coating method with amorphous cr alloy

Abstract: PURPOSE:To coat a substrate with an amorphous Cr alloy having extremely high corrosion resistance at a high speed with satisfactory work efficiency by putting the substrate in an aqueous soln. type bath contg. a tervalent chromium salt and a salt of an oxyacid of phosphorus as essential components and by supplying a pulsating current under specified conditions. CONSTITUTION:An aqueous soln. type bath contg. a tervalent chromium salt such as CrCl.6H2O and an oxyacid of phosphorus or a salt thereof such as phosphoric acid or sodium hypophosphite as essential components is prepd. A substrate is put in the bath and a pulsating current ip having a pulse cycle of 0.01-100ms on-off time is supplied at >1- current density to carry out the electrolytic coating of the substrate with an amorphous Cr alloy. A salt of an iron group metal such as FeSO4 and a metallic salt having a high m.p. such as Na2MoO4.2H2O may be added to the bath.