Showing papers on "Sodium hypophosphite published in 1997"

Electroless plating of metallic features on nonmetallic or semiconductor layer without extraneous plating

Abstract: In the manufacture of a microelectronic component having metallic features on a polyimide layer, the metallic features being spaced from one another by gaps, at least some of which gaps have widths in a range from about one micron to about 500 microns, corrosion protection is provided by plating those features by electroless deposition of a nickel-phosphorus alloy forming a layer having a thickness in a range from about 200 Å to about 3000 Å, at a rate of about 100 Å per minute, in an aqueous plating bath comprising nickel sulfate hexahydrate in an amount of about 5.5 grams per liter, sodium hypophosphite in an amount of about six grams per liter, boric acid in an amount of about 30 grams per liter, sodium citrate in an amount of about 45 grams per liter, lead acetate in an amount of about one part per million by weight of lead, and a surfactant in an amount of about 0.1 grams per liter. The bath has a temperature of about 72° C. and a pH of about 8.1. The gaps having widths of at least one micron remain essentially free of extraneous plating.

Deposition of high wear resistance of Ni‐composite coatings

Abstract: Electrodeposited Ni‐P composite coatings incorporating a variety of inorganic particles were obtained from Watt’s nickel bath containing sodium hypophosphite The mechanism of co‐deposition of various particles (SiC, Al2O3, quartz and sand) was studied in view of the electro‐kinetic charge characterizing the solid particles Means to improve the mobility of the particles in the plating solution were investigated using sodium oleate as surface active agent The purpose was to increase particle content in the coating to attain high hardness values Special attention was given to the deposition process using SiC particles The surface morphology, hardness and wear resistance of the composite coatings were determined Hardness values were maximized by simple heat treatment in air atmosphere which led to the precipitation of the hard Ni3P phase Sound, coherent and high wear resistance coatings could be produced

Electrochemical characterization of Fe-Ni-P alloy electrodeposition

Abstract: In this study we have investigated the electrodeposition of amorphous iron–nickel–phosphorus alloys from a sulfate electrolyte. Fe-Ni alloys are known to exhibit an ’anomalous‘ type of plating behaviour in which deposition of the less noble metal is favoured. We have found that the codeposition of phosphorus from hypophosphite in the electrolyte led to a reversal to a ’normal‘ behaviour. This reversal was due both to the suppression of iron and enhancement of nickel partial currents. The overall deposition process is dominated by the hydrogen evolution reaction. This is exacerbated by the low pH needed to codeposit sufficient phosphorus to achieve an amorphous structure.

Method for solid phase polymerization

Abstract: An improved method for increasing the relative viscosity and molecular weight of a polyamide polymer (such as nylon 6,6, nylon 6, and the like) while in the solid state involving the use of a phosphorus-containing catalyst (such as 2(2'-pyrydyl)ethyl phosphonic acid, sodium hypophosphite, tolyl phosphinate and manganese hypophosphite or the like) in combination with an oxygen free gas characterized by a low dew point (typically below 30 °C and preferably below -30 °C). Operational and commercial advantages are derived from the combination of using simultaneously a phosphorus-containing catalyst and the recycle of very low dew point drying gas at lower operating temperatures than previously employed in conducting solid phase polymerization of polyamide polymer. Such a process is of particular value during the production of terpolyamide and multipolyamide polymer intended for use in colored nylon fiber manufacture.

Characterisation of Ni–P electroless deposits with moderate phosphorus content

Abstract: The influence of the phosphorus content on hardness, structure, and morphology of electro less Ni–P deposits on an AISI 1020 steel substrate was investigated. The deposits were prepared from acidic plating solutions based on nickel chloride, as the source of nickel cations, and sodium hypophosphite, as the reducing agent. Coatings with an average of 4·68 and 6·65 wt-%P were obtained, which were analysed using glow discharge optical emission spectroscopy. Variation of phosphorus content with coating thickness was observed when the pH of the solution was not controlled rigorously. The coated samples were annealed at 170°C for 1 h in order to eliminate hydrogen, then post-treated for 25 h at 260°C or 1h at 400°C. X-ray diffraction studies indicated that the as deposited coatings presented a microcrystalline/amorphous or an amorphous structure depending on the phosphorus content. After both heat treatments, a strong (111) preferred orientation was found and coarsening of the grain sizes occurred with ...

Effect of Catalysts on the Thermal Characteristics of Cotton Citric Acid DP Finishes

Abstract: Citric acid-based durable press finishes catalyzed with various levels of sodium hypophosphite, sodium phosphate, or sodium phosphite have been studied systematically. Thermal characteristics are compared, beginning with visual examination of the thermograms and quantitation of multiple parameters primarily from thermogravimetric analyses, and combinations of parameters are examined in three-dimensional graphs. Such combinations are successfully used to distinguish between finishes and assess finish levels. Comparisons of samples from this series with those of previous studies show that each sample is unique. Finish identification depends critically on the catalyst used, and therefore these citric acid finishes can be recognized as different from finishes based on 1,3-dimethylol 4,5-dihydroxyethyleneurea (dmdheu) and magnesium chloride/citric acid catalyst. Successful identification of specimens using only thermoanalytical techniques is an indication that quality control in textile mills is feasible with these procedures.

Method of treating electroless plating bath

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 2 PO 3 , and recovering the nickel sulfate. According to this method, it is possible to simply, positively and inexpensively separate phosphite ions, without inclusion of any impurity, from an aged electroless plating bath in which phosphite ions are accumulated in a large amount, and to simply recover nickel sulfate from the nickel phosphite thus separated from the plating bath and effectively use the nickel sulfate as a reactive medium for removing a plating bath component or phosphite ions.

Method for nickel plating onto aluminum electrode

Abstract: PROBLEM TO BE SOLVED: To obtain a method for electroless nickel plating onto an aluminum electrode required for formation of a highly reliable electrode. SOLUTION: Nucleus is formed of a deposit 14 of palladium on an aluminum electrode 12 using an activation liquid and a reducing agent, i.e., sodium hypophosphite, is dissolved into pure water. While conditioning the pH in the range of 9.0-12.0 using a sodium hydroxide solution, water is added to produce a solution 15 having total volume of 1000mL. The aluminum electrode 12 of semiconductor element is immersed into the solution 15 and then plated using an oxidation-reduction electroless plating liquid of 80-90 deg.C having pH in the range of 5.0-6.8 thus depositing nickel 16 containing phosphorus on all aluminum electrode 12 of semiconductor element.

Electroless composite plating treatment of metallic material

Abstract: PURPOSE: To provide the treatment by which a mold material can freely be selected from metallic materials having excellent workability and the durability of a mold after forming can be secured through performing the treatment for enhancing durability of the mold based on physical and chemical considerations and accordingly, the working period for forming the mold can also be shortened. CONSTITUTION: In this treatment, a metallic material to be heated is placed in a dual electroless plating tank and at the same time, an electroless composite plating bath is supplied to the plating tank. At this time, desirably, the plating tank is heated with steam so that the treating temp. becomes equal to 92 deg.C of the plating bath temp. and also the plating bath is supplied while stirring it. As the electroless composite plating bath, a bath obtained by using an Ni-P electroless plating bath as its base and adding ceramics or the like to this Ni-P electroless plating bath is employed to subject the metallic material to composite plating treatment with e.g. Ni-P-SiC. In this experiment, sodium hypophosphite (NaH2 PO2 .H2 O) is used as a component of the electroless composite plating bath.

High-effective sewage purifying agent

Abstract: A high-effective sewage decontaminant uses several chemical raw materials, such as sodium hypophosphite, sodium phosphate, trisodium phosphate, iron trichloride, calcium oxide emulsion, aluminium potassium sulphate, hydrochloric acid and sulphuric acid, through crushing, dissolving, mixing, stirring, settling, filtering and packaging to obtain the product. Four kinds of different components are developed to suit different waste waters and may be separately used for such cases as paper mill waste water, radioactire element chemical works waste water, general plant waste water and different raw-waters, and the water quality after treatment can reach the discharging stardard stipulated by the state environmental protection sector. Its advantages are high-effect, quickness, cheapness and easyapplication.

Electroless Ni-Fe Alloy Depositions Using DMAB and NaPH2O2 as a Reducing Agent

Abstract: Electroless Fe-Ni alloy (20Fe-80Ni permalloy) deposition has been studied in two types of solution containing either sodium hypophosphite (NaPH2O2) or dimethylamine borane (DMAB) as a reducing agent and trisodium citrate as a complexing agent. The partial current densities of Ni and Fe in the alloys electrodeposited at constant potentials showed that less noble Fe exhibited strongly induced codeposition. The alloy deposition rate was obtained both by the superposition of anodic and cathodic partial polarization curves in each solution of 02 for the FN ratio (Fe2+/(Fe2++Ni2+)) and by Tafel extrapolation in the total polarization curves of the complete electroless plating solution. The deposition rate determined by the weight gain in the DMAB plating bath was consistent with those obtained by electrochemical polarization measurements.The effect of pH and the metallic ion concentration ratio, i e, the FN ratio, of NaPH2O2 and DMAB plating bath on the Fe content in alloys and the deposition rate was examined. The optimum condition for obtaining the alloy in the DMAB plating bath was determined to be pH 95-10 at an FN ratio of 03.The Fe content of NaPH2O2 plating bath was about 10% at an FN ratio of 02-06, which is low compared to the monotonically increased 45% at an FN ratio of 08 of DMAB plating bath. These results suggest that the phosphorous element in the reducing agent retards Fe deposition.The X-ray diffraction patterns of the deposits maintained -10V for 1h exhibited three distinct 111, 200, and 220 peaks. The electroless plating deposit showed the preferred orientation of the 111 peak accompanying a broadening peak.

Study of the role of sodium hypophosphite in electroless nickel bath solution

Abstract: Cyclic voltametric investigations have been made to understand the electrochemical behaviour of sodium hypophosphite in electroless plating bath solution. The possible reaction steps at the anode and cathode have been identified. An ECE type of mechanism appears to be operative in the overall reaction during electroless plating. Both organic and inorganic species in the bath solution influence the voltammetric pattern of the hypophosphite. Temperature enhances the peak currents and changes the reaction mechanism. The oxidation potentials of the reaction steps vary with temperature and also the presence of organic components in the both solution.

Modeling of nickel surface state in electrocatalytic hypophosphite oxidation according to on-line electrochemical mass spectrometry studies

Abstract: Computer simulation of possible distributions of H ad and D ad atoms developed on nickel surface as a result of partial reactions of anodic hypophosphite oxidation and cathodic proton (deuteron) discharge from water respectively was used for modeling of the catalyst surface state according to on-line electrochemical mass spectrometry data. The simpliest lattice-gas model gives a probable qualitative description of the catalyst surface state and allows the genesis of electrocatalytic properties of nickel with the electrode potential to be followed. Location of anodic and cathodic half-reactions at special types of sites was evidenced, leading to formation of non-equilibrium H 2 , HD and D 2 mixtures with the lower HD content than that predicted theoretically.

Method for producing electro-conductive fibers

Abstract: Disclosed is a method for fabricating an electro-conductive fiber, which comprises the steps of treating a basic fiber composed of filaments of polyester or acrylic series with 2 to 3 gr of sodium hydroxide and non-ionic surfactant at a temperature of 30 to 40 DEG C for about five minutes, washing sufficiently the treated fiber in a hot bath of 60 to 70 DEG C, etching the washed fiber with a liquid solution mixed with hydrochloric acid of 50 ml and nitric acid of 10 ml at room temperature for about thirty minutes, immersing the etched fiber in a liquid solution mixed with palladium chloride of 2 gr and tin chloride of 2 gr added with hydrochloric acid (HCl) at a temperature of 20 to 50 DEG C for about ten minutes after washing, washing to remove the tin from the fiber, and immersing the fiber in a liquid solution of sodium hydroxide of 50 gr at room temperature to remove residual tin, immersing the fiber in a liquid solution mixed with cupric sulfate of 20 gr, sodium hydroxide of 40 gr and rosolic salt of 160 gr added with 37 % formalin at a temperature of 40 to 50 DEG C for 10 to 15 minutes, and immersing the fiber in a liquid solution mixed with sulfate nickel of 20 gr, citric acid of 15 gr and sodium hypophosphite of 30 gr at a temperature of 30 to 40 DEG C for about ten minutes (nickel formed with a thickness of about 0,2 mu m). In this way, the traditional fiber is coated with a very thin film of electrical conductivity, which is formed around the fiber nucleus of non-electrical conductivity, so that the fiber has electrical conductivity without losing the desired physical properties of the traditional fiber.

Simulation of electroless plating of nickel with sodium hypophosphite

Abstract: The quantitative relationship between the rate of electroless plating and the solution composition was studied for the first time using a combined regression equation. A model is proposed accounting for the contribution of each component of a multicomponent system and their interaction and describing quantitatively the course of the reaction.