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Showing papers on "Electroplating published in 1987"


Journal ArticleDOI
TL;DR: In this paper, a method was developed to produce composition-modulated alloys by electrodeposition for the copper-nickel couple, where the Salts of the two component metals are dissolved in a common electrolyte and the potential is alternately pulsed for fixed durations between values above and below the reduction potential of the less noble component.
Abstract: A method has been developed to produce composition-modulated alloys by electrodeposition. The method was demonstrated for the copper-nickel couple. Salts of the two component metals are dissolved in a common electrolyte and the potential is alternately pulsed for fixed durations between values above and below the reduction potential of the less noble component. Co-deposition of the nobler metal into the other metal layer is diminished by setting unfavourable diffusion conditions during the more cathodic pulse. Modulation was achieved down to 0.8 nm thick layers. The resulting composition-modulated alloys were analysed by Auger spectroscopy and X-ray diffraction.

140 citations


Journal ArticleDOI
TL;DR: In this article, the operating conditions for zinc and nickel codeposition from chloride baths were studied in order to obtain alloys containing up to 20% nickel. Satisfactory deposits were produced at 50°C using current densities ranging from 5 to 20 mA cm−2 and nickel to zinc ratios ranging from 6.8 to 37.5%.
Abstract: Operating conditions for zinc and nickel codeposition from chloride baths were studied in order to obtain alloys containing up to 20% nickel. Satisfactory deposits were produced at 50°C using current densities ranging from 5 to 20 mA cm−2 and nickel to zinc ratios ranging from 6.8 to 37.5%.

104 citations


Journal ArticleDOI
TL;DR: In this paper, enhanced Raman spectra were detected for CN− absorbed on thin Ni, Co, Cu and Zn layers deposited from cyanide plating baths onto silver substrate electrodes roughened in a preceding controlled oxidation-reduction cycle.

90 citations


Journal ArticleDOI
S. Swathirajan1
TL;DR: In this paper, a model involving the coupling of charge transfer and heterogeneous interaction is proposed to calculate the partial Zn currents during the deposition of the α-phase of Zn + Ni in the absence of mass transfer limitations.

89 citations



Journal ArticleDOI
TL;DR: In this paper, the electrolytic reduction mechanisms of K2SiF6 and K2TiF6 solutions in LiF-KF and LiF NaF KF eutectic mixtures have been studied at temperatures between 550 and 850°C.
Abstract: The electrolytic reduction mechanisms of K2SiF6 and K2TiF6 solutions in LiF-KF and LiF-NaF-KF eutectic mixtures have been studied at temperatures between 550 and 850°C.

70 citations


Journal ArticleDOI
TL;DR: In this paper, the migration and complexation du zinc par les ions chlorure, de la composition du depot electrolytique d'un alliage, are analyzed par un modele de transfert de masse.
Abstract: Analyse par un modele de transfert de masse, incluant la migration et la complexation du zinc par les ions chlorure, de la composition du depot electrolytique d'un alliage. Application au systeme Zinc-Nickel-Chlorure

62 citations


Journal ArticleDOI
TL;DR: The electrolytic treatment of less resistant metals such as iron, copper and nickel with tantalum or niobium has been carried out in K2TaF7-LiF-NaF or K2NbF7 -LiF NaF solutions in the 550 to 1050°C temperature range as discussed by the authors.
Abstract: The electrolytic treatment of less resistant metals such as iron, copper and nickel with tantalum or niobium has been carried out in K2TaF7-LiF-NaF or K2NbF7-LiF-NaF solutions in the 550 to 1050°C temperature range Two kinds of experiments have been used (i) At lower temperatures, electroplating with pure tantalum and niobium on inert cathodes was performed The electrodeposition mechanism of each metal was studied and coherent electroplates were prepared which were tested in electrocatalytic applications (ii) At higher temperatures (850–1050°C), using nickel cathodes, intermetallic compounds were obtained at more positive potentials than that for pure electrodeposition (Ta2Ni, TaNi, TaNi2, TaNi3, NbNi, NbNi3) The electrowinning of stable TaNi3 and NbNi3 layers was carried out by the metalliding process which makes these materials resistant to corrosion in various media Further, a study of the kinetics of growth of the diffusion layer allowed a diffusion parameter to be determined which was in agreement with other results obtained by conventional methods

57 citations


Journal ArticleDOI
TL;DR: In this paper, images of a graphite surface before and after electroplating with gold were obtained without ever removing the sample from the gold-coated solution, and these images suggest a bright future for in situ investigations of processes with scanning tunneling microscopy.

56 citations


Patent
16 Oct 1987
TL;DR: In this article, the optical surfaces of a mold element are formed by intimate contact with suitably contoured or profiled and lapped surfaces of one or more optical mold insert elements.
Abstract: An improved method and apparatus for high-pressure injection or compression molding of optical thermoplastic parts such as lenses or optical disks, wherein the optical surfaces of a molded part are formed by intimate contact with suitably contoured or profiled and lapped surfaces of one or more optical mold insert elements. The optical surface of such mold element is of a different composition metallurgically than is the bulk composition of the rest of the mold element, thus allowing for optimum selection for materials-of-construction parameters (such as heat transfer, load-bearing quality, and ease of fabrication) in the bulk properties of the substrate metal, without necessarily trading off against optimum optical surface characteristics (such as imperviousness to chemical oxidation or attack, resistance to scratching and abrasion, ease of generating optical surface therein). Thus, a one-piece construction (not mechanically joined from separate elements) of a seamless nature, generally consists of at least one layer of relatively thick electroplating (nickel or chromium) onto a beryllium-copper alloy substrate of certain specified mechanical and thermal characteristics. Heat transfer is further improved by means of machined flow channels provided for circulating liquid coolants. A most preferred mold element construction consists of, first, a machined beryllium-copper substrate onto which a thick watts nickel plating was deposited, followed by abrasive lapping to create the specified surface contour to a high level of microstructure perfection and smoothness, onto which a final thin hardcasting of either vacuum-deposited TiN or flash plate of chromium is deposited.

44 citations


Patent
03 Mar 1987
TL;DR: In this article, the use of electrolytic cells comprising an anode and cathode, sulfuric acid, and a chalcogen-containing compound was proposed for depositing metals on or removing metals from substrates.
Abstract: Methods for depositing metals on or removing metals from substrates are provided which involve the use of electrolytic cells comprising an anode and cathode, sulfuric acid, and a chalcogen-containing compound soluble in said bath and having the empirical formula ##STR1## wherein X is a chalcogen, each of R1 and R2 is selected from hydrogen, NR3 R4 and NR5, at least one of R1 and R2 is other than hydrogen, each of R3 and R4 is hydrogen or a monovalent organic radical, and R5 is a divalent organic radical, in which the molar ratio of the chalcogen compound to sulfuric acid is about 1 or more, and the molar ratio of water to the combination of acid and chalcogen compound is about 20 or less. These methods enable the use of higher concentrations of strong acids than would otherwise be possible, minimize hydrogen and/or oxygen evolution at the electrodes with attendant advantages, and are useful for electroplating (including immersion plating), electroforming, electrolytic machining, electropolishing, electrolytic roughening, anodizing and electrowinning among others.

Patent
23 Mar 1987
TL;DR: In this paper, a conductive copper paste composition is adapted to yield a highly conductive film receptive to solders without pretreatment, which can be used in such applications as electrode and throughhole connections, formation of electromagnetic and electrostatic shield layers, and so on in the manufacture and assembly of electronic components and circuits.
Abstract: A conductive copper paste composition is adapted to yield a highly conductive film receptive to solders without pretreatment. This conductive paste comprises a copper metal powder, a resin component including a thermosetting resin, and an assortment of additives. In use, the paste is applied to an insulation substrate to a predetermined circuit pattern and cured in situ. Soldering can then be performed directly on the cured circuit. This contributes not only to the conductivity of the circuit but dispenses with the activation treatment and electroless plating or electroplating that have heretofore been essential prior to soldering. The invention, therefore, results in a substantial curtailment of production process and a proportional economic advantage. In addition, this conductive paste can be used in such applications as electrode and through-hole connections, formation of electromagnetic and electrostatic shield layers, and so on in the manufacture and assembly of electronic components and circuits.

Journal ArticleDOI
TL;DR: An overview of the requirements for the electroplating of refractory metals from molten salts is presented, followed by a discussion of recent electrochemical studies which have been carried out to delineate the solution chemistry of alkali metal halide plating baths.
Abstract: An overview of the requirements for the electroplating of refractory metals from molten salts is presented, followed by a discussion of recent electrochemical studies which have been carried out to delineate the solution chemistry of alkali metal halide plating baths. New results for halide baths involving chromium and molybdenum are presented and considered from the view of both solution chemistry and the electrocrystallization processes of these metals. Advantages and disadvantages of these electrolytes are discussed in the context of plating cell development and pulse modulated plating techniques.

Journal ArticleDOI
TL;DR: The theory of a technique based on the observation of the mixed potential as a function of agitation, concentration of the reducing agent and concentration of metal ions is presented in this article, where it is shown that in electroless copper plating the copper deposition reaction is diffusion-controlled while the formaldehyde decomposition reaction is activation-controlled.
Abstract: Electroless plating reactions are classified according to four overall reaction schemes in which each partial reaction is either under diffusion control or electrochemical control. The theory of a technique based on the observation of the mixed potential as a function of agitation, concentration of the reducing agent and concentration of metal ions is presented. Using this technique it is shown that in electroless copper plating the copper deposition reaction is diffusion-controlled while the formaldehyde decomposition reaction is activation-controlled. Values of the kinetic and mechanistic parameters for the partial reactions obtained by this method and by other electrochemical methods indicate that the two partial reactions are not independent of each other.

Patent
29 Sep 1987
TL;DR: An exterior stainless steel sheet is provided comprising a stainless steel substrate and a coating layer formed on one surface of the steel substrate from Al, Al alloy, Zn or Zn alloy to a thickness of 0.1 to 70 μm as discussed by the authors.
Abstract: An exterior stainless steel sheet is provided comprising a stainless steel substrate and a coating layer formed on one surface of the steel substrate from Al, Al alloy, Zn or Zn alloy to a thickness of 0.1 to 70 μm, preferably 1 to 70 μm. A Zn or Zn-Ni alloy plated stainless steel strip is prepared by degreasing a stainless steel strip, substantially activating the surface of the strip, and electroplating the strip in a zinc or zinc-nickel alloy plating bath at pH 3.5 or lower. During electroplating of one side, the other side of the strip not to be plated is covered with a protective film. A stainless steel sheet comprising a stainless steel substrate and a coating layer formed on one surface of the steel substrate from Zn or Zn alloy to a thickness of 0.1 to 50 μm, preferably 1 to 50 μm is useful in preparing welded pipes.

Patent
16 Jan 1987
TL;DR: In this article, a test element of the sensor is formed of a thick, high resistivity substrate, such as stainless steel, upon which is electroplated a thin test coating of material to be tested in a corrosive environment.
Abstract: A high sensitivity electroplating or corrosion sensor and method for sensing, employing a relatively strong, self-supporting electrically conductive substrate of high resistivity and a test coating that is electroplated directly onto the substrate. For corrosion monitoring, a test element of the sensor is formed of a thick, high resistivity substrate, such as stainless steel, upon which is electroplated a thin test coating of material to be tested in a corrosive environment. For many applications, the ratio of resistivity of the substrate to resistivity of the test coating is substantially equal to the ratio of thickness of the substrate to thickness of the test coating, which ratio may be about 40 to 1. The sensor may be employed in the monitoring of electroplating by immersing the stainless steel substrate in the electrolytic bath with the object to be plated and measuring the decreasing parallel resistance of the substrate and coating that is plated upon the substrate during a plating of the object. To decrease noise due to currents generated in the plating or corrosion sensor by external currents, the power supply is connected to the sensor substrate to cause equal and opposite current components to flow in the substrate.

Journal ArticleDOI
TL;DR: In this article, the relationship between the electrochemical parameters and the resulting structures of chromium electrodeposits obtained by electrolysing chromous chloride (CrCl2) dissolved in the LiCl-KCl eutectic have been established.
Abstract: The relationships between the electrochemical parameters (which can be controlled) and the resulting structures of chromium electrodeposits obtained by electrolysing chromous chloride (CrCl2) dissolved in the LiCl-KCl eutectic have been established. The electrodeposition of chromium under ordinary potentiostatic conditions leads to pure chromium but this is not in a form to provide an adequate protective coating as it is difficult to avoid dendrite formation and low initial coverage together. These limitations can be overcome by the sequential use of a high overpotential pulse to initiate good coverage and continuing electrodeposition at low overpotential to minimize dendrite formation. The structures and morphologies of chromium electroplates were optimized. The good protective coatings that resulted were adherent, coherent and reasonably free of cracks and pores. The macro-and microthrowing powers of the bath were excellent and the high purity of the chromium electroplates led to low (130–280 HV) measured microhardness.

Patent
09 Oct 1987
TL;DR: An apparatus and method for preparing conductive bridges to electrically couple discrete electrical conductors arranged on opposed surfaces of a common substrate is described in this article, where the substrate is exposed to the vacuum source through a plurality of spaced-apart bores of relatively small diameter, with the vacuum diffusion layer in the form of a web of filter paper tracking and moving in synchronism with the substrate.
Abstract: An apparatus and method for preparing conductive bridges to electrically couple discrete electrical conductors arranged on opposed surfaces of a common substrate The method and apparatus utilized includes subjecting the bore or opening in the substrate to the force of vacuum applied through a vacuum diffusion barrier The substrate is exposed to the vacuum source through a plurality of spaced-apart bores of relatively small diameter, with the vacuum diffusion layer being in the form of a web of filter paper tracking and moving in synchronism with the substrate Conventional silk screening techniques are utilized to form the conductors and bridges, with polymer thick conductive fluids being employed as the printing medium Multiple layers of conductors may be formed, with dual-sided circuitry being applied to the substrate The multiple layers are fabricated by initially plating a layer of metal upon the exposed surface of the polymer thick conductive films, and thereafter printing a defined pattern of dielectric upon the electroplated copper Subsequently, a second polymer thick conductive fluid is employed as a printing medium upon the surface of the dielectric, with contact to the copper being available through vias formed in the dielectric layer Following cure of such second layer, the exposed surfaces may be plated with a film of copper, nickel or other suitable metal

Patent
19 Jun 1987
TL;DR: In this paper, a titled alloy for an electrically conductive roll for electroplating is presented, which consists of, by weight, 0.2-3% C, Si, Mn, Ni, Cr, 2-15% W, and 10% Fe as an impurity and the balance Co.
Abstract: PURPOSE:To obtain the titled alloy having superior corrosion and wear resistances and giving a roll from which metal stuck to the surface of the body during plating is easily stripped by adding prescribed amounts of C, Si, Mn, Ni, Cr and W to Co and restricting the amount of Fe as an impurity. CONSTITUTION:This alloy for an electrically conductive roll for electroplating consists of, by weight, 0.2-3% C, <=2% Si, <=2% Mn, <=5% Ni, 20-35% Cr, 2-15% W, <=10% Fe as an impurity and the balance Co. The alloy has superior corrosion and wear resistances in a corrosive environment contg. a plating soln. The alloy is hardly plated and metal for plating has low bonding strength to the alloy. When the alloy is used, the troublesome frequent exchange of a roll and large polishing expenses for regenerating the roll are considerably reduced, stable continuous plating operation is maintained and the quality of a plated product is improved and stabilized.

Patent
16 Dec 1987
TL;DR: In this article, a method and apparatus for improving the integrity of metal plated composites is described, which is achieved by first irradiating a nickel plated substrate, prior to application of a noble metal plating layer, to smooth any surface discontinuities or irregularities.
Abstract: A method and apparatus for improving the integrity of metal plated composites is disclosed. Plating improvements are achieved by first irradiating a nickel plated substrate, prior to application of a noble metal plating layer, to smooth any surface discontinuities or irregularities. Excimer laser pulses, having a duration of less than 100 nanoseconds, are employed to partially liquefy the upper surface of the nickel plating on the substrate. This invention is compatible with conventional plating processes, such as electroplating.

Journal ArticleDOI
Abstract: Crystallographic aspects of the electrodeposition of zinc on low-carbon steel sheets have been examined with particular emphasis on the hetero-epitaxy. The hetero-epitaxial growth of zinc crystals largely depends on the surface condition of the ferrite substrate and occurs even at a current density as high as 2 A cm−2 by reducing the surface oxidation layer. The surface roughness of the substrate induces local disturbance in hetero-epitaxial growth. The orientation relationship between zinc crystals and the ferrite substrate can be interpreted in terms of the minimum misfit atomic arrangements between both phases.

Patent
18 Jun 1987
TL;DR: In this article, the formation of tetravalent tin and stannic oxide sludge is prevented or prevented by using a bath with a soluble divalent tin compound, a soluble alkyl or alkylol sulfonic acid at least one wetting agent, and a hydroxyl phenyl compound reducing agent.
Abstract: Baths and methods for electroplating tin or tin-lead alloys wherein the formation of tetravalent tin and stannic oxide sludge is reduced or prevented. These baths contain a soluble divalent tin compound, a soluble alkyl or alkylol sulfonic acid at least one wetting agent, and a hydroxyl phenyl compound reducing agent. Other compounds may be added to the bath for improving its performance during electroplating.

Patent
03 Mar 1987
TL;DR: In this paper, the empirical formula of the chalcogen compound to sulfuric acid is about 1 or more, and the molar ratio of water to the combination of acid and chalgogen compound is about 20 or less.
Abstract: Electrolytic cells, suitable for depositing a metal on or removing a metal from a substrate, are provided which comprise an anode and cathode, sulfuric acid, an a chalcogen-containing compound soluble in said bath and having the empirical formula ##STR1## wherein X is a chalcogen, each of R1 and R2 is selected from hydrogen, NR3 R4 and NR5, at least one of R1 and R2 is other than hydrogen, each of R3 and R4 is hydrogen or a monovalent organic radical, and R5 is a divalent organic radical, in which the molar ratio of the chalcogen compound to sulfuric acid is about 1 or more, and the molar ratio of water to the combination of acid and chalcogen compound is about 20 or less. These cells enable the use of higher concentrations of sulfuric acid than would otherwise be possible, minimize hydrogen and/or oxygen evolution at the electrodes with attendant advantages, and are useful in a variety of methods such as electroplating (including immersion plating), electroforming, electrolytic machining, electropolishing, electrolytic roughening, anodizing, electrowinning and as storage batteries.

Journal ArticleDOI
TL;DR: In this paper, a multwavelength multicomponent analysis for copper and nickel is explored within the spectral range 230-900 nm in order to enable copper (⩾0.2 g l −1 ) and nickel to be determined simultaneously even at high (20 l − 1 ) or nickel concentrations in industrial electroplating baths.

Journal ArticleDOI
R. J. von Gutfeld1
TL;DR: In this article, a review of laser-enhanced plating and etching with emphasis on the chemical, electrochemical, and thermal mechanisms giving rise to the experimental observations is presented.
Abstract: We review our work on laser-enhanced plating and etching with emphasis on the chemical, electrochemical, and thermal mechanisms giving rise to the experimental observations. The metallurgical properties of the deposits and their applications, particularly in the field of microelectronics, are also discussed. The work on laser-enhanced electroplating and electrodeless plating includes high-speed deposition of copper, gold, and nickel by using the argon-ion laser as the source of localized energy. Deposition rates up to 3 orders of magnitude higher have been observed for laser-irradiated regions compared with nonirradiated ones. Mechanisms responsible for the plating enhancement are (1) enhanced chemical and electrochemical kinetics with increased temperature, (2) shifts in the local rest potential with temperature, and (3) local agitation of the solution as a result of large temperature gradients. Applications of these techniques to circuit design and repair as well as to high-speed plating of precious metals onto electrical contact areas of microelectronic circuits are considered. Experiments on high-speed laser-enhanced etching of several dielectrics are also reviewed. Volume removal rates as high as 106μm3/sec for an alumina/TiC ceramic and 105μm3/sec for 〈111〉 silicon using KOH as the etchant have been obtained.

Patent
21 Jan 1987
TL;DR: By using such processes as depositing, electroplating and metallurgical chemical cladding, etc., three layers-metallic carbide film, alloy surface layer as well as electroplated metal skin, are cladded on the diamond surface as mentioned in this paper.
Abstract: By using such processes as depositing, electroplating and metallurgical chemical cladding, etc., three layers-metallic carbide film, alloy surface layer as well as electroplating metal skin, are cladded on the diamond surface. That overcomes the difficulty that diamond can not adhesive to and be wetted by ordinary low-m.pt. alloys. The metallized diamond can be used and preserved in the same way as ordinary metal powder-granules, so that the lifespan of tool made of this diamond is laygely prolongated.


Patent
16 Jan 1987
TL;DR: In this paper, high strength steel wire for use e.g. in tire reinforcement is treated so as to have a cementite free surface region, which can be achieved by electroplating or other coating methods, or be decarburizing the surface.
Abstract: High strength steel wire for use e.g. in tire reinforcement is treated so as to have a cementite free surface region. This can be achieved by electroplating or other coating methods, or be decarburizing the surface. The wire has increased resistance to hydrogen embrittlement and corrosion fatigue. The wire with its ferrous surface region is then covered with a rubber adherent outer layer of e.g. brass.

Patent
05 Mar 1987
TL;DR: A reactionless thermionic cathode for electronic tubes consists of a metallic or ceramic support and an alloy, preferably an intermetallic compound, containing the actual emission-promoting element, with a metal from the group comprising those of the VIIIth vertical row of the periodic table and rhenium.
Abstract: A reactionless thermionic cathode for electronic tubes consists of a metallic or ceramic support and an alloy, preferably an intermetallic compound, containing the actual emission-promoting element, with a metal from the group comprising those of the VIIIth vertical row of the periodic table and rhenium. The preferred activation substances are platinides of the elements having a low electron work function, predominantly Ba and La. The cathode is manufactured by wet-mechanical, cataphoretic or electroplating application of the activation substance to the support or by infiltration of the porous support having a pore volume of at least 10%. High emission current densities are obtained at relatively low operating temperatures.

Patent
15 Apr 1987
TL;DR: In this paper, the authors describe a process for plating nickel upon a surface of a workpiece made of stainless steel, where the workpiece is immersed in an electrolytic sulfuric acid bath, with the work piece anodically connected.
Abstract: In a process for plating nickel upon a surface of a workpiece made of stainless steel, the workpiece is immersed in an electrolytic sulfuric acid bath, with the workpiece anodically connected. Thus, DC current flows from the workpiece, through the bath, to a separate cathode in the bath. Thereafter, the sulfuric acid is rinsed from the workpiece and the workpiece surface is electroplated with nickel which will strongly adhere to the surface. Finally, the nickel-plated part may be conventionally electroplated with chrome.