Utilizing Organic Compound-containing Bath Patents (Class 205/290)
  • Patent number: 11905613
    Abstract: The present invention refers to an electroplating bath for depositing chromium which comprises at least one trivalent chromium salt, at least one complexing agent, at least one halogen salt and optionally further additives. Moreover, the invention refers to a process for depositing chromium on a substrate using the mentioned electroplating bath.
    Type: Grant
    Filed: March 4, 2020
    Date of Patent: February 20, 2024
    Assignee: Coventya S.p.a.
    Inventors: Diego Dal Zilio, Gianluigi Schiavon
  • Patent number: 11781232
    Abstract: An aqueous electroplating bath is disclosed. The aqueous trivalent chromium bath comprises:—trivalent chromium cations in an amount of 0.12-0.276 mol/l,—ammonium ions in an amount of 4.0-6.0 mol/l, and—carboxylate ions in an amount of 2.0-7.4 mol/l, and the molar ratio of trivalent chromium cations to the carboxylate ions is 0.016-0.099, and the pH of the aqueous trivalent chromium bath is 2-6.
    Type: Grant
    Filed: April 21, 2021
    Date of Patent: October 10, 2023
    Assignee: Savroc Ltd
    Inventors: Jussi Räisä, Arto Yli-Pentti
  • Patent number: 8372259
    Abstract: A chromium plating bath containing trivalent chromium ions and hexavalent chromium ions is prepared by a method including the steps of: (A) mixing chromic acid and an organic acid in an aqueous solution containing these acids and reducing chromic acid by the organic acid so as to prepare an aqueous solution not containing hexavalent chromium ions; (B) adding a pH adjustor to the aqueous solution not containing hexavalent chromium ions so as to adjust pH to a value of 1 to 4; and (C) further adding chromic acid to the aqueous solution not containing hexavalent chromium ions and having undergone the pH adjustment so as to prepare an aqueous solution containing trivalent chromium ions and hexavalent chromium ions. The chromium plating bath containing both trivalent chromium ions and hexavalent chromium ions can be prepared while easily and assuredly adjusting the contents (content ratio) of trivalent chromium ions and hexavalent chromium ions to predetermined values (a predetermined value).
    Type: Grant
    Filed: November 17, 2009
    Date of Patent: February 12, 2013
    Assignee: C. Uyemura & Co., Ltd.
    Inventors: Toru Murakami, Suhaimi Hamid, Ryo Maeda
  • Patent number: 8282808
    Abstract: The present invention relates to the use of phosphinic acids and/or phosphonic acids and salts thereof, preferably as surface-active compounds, in redox processes, in particular in electroplating technology, particularly preferably in electroplating baths, and to electroplating baths comprising these compounds.
    Type: Grant
    Filed: May 4, 2007
    Date of Patent: October 9, 2012
    Assignee: Merck Patent GmbH
    Inventors: Wolfgang Hierse, Nikolai Ignatyev
  • Patent number: 8273235
    Abstract: An aqueous acidic trivalent chromium electrolyte comprising trivalent chromium ions and a complexing agent for maintaining the trivalent chromium ions in solution is provided in which the aqueous electrolyte comprises additives capable of producing a coating on a substrate having a desired dark hue. The additives typically comprise a dispersion of colloidal silica and an additional additive selected from thiocyanate ions and/or iron ions. The electrolyte is used in a method of producing the desired dark-hued decorative chromium coating on a substrate by electrodeposition.
    Type: Grant
    Filed: November 5, 2010
    Date of Patent: September 25, 2012
    Inventors: Roshan V Chapaneri, Richard G Tooth, Roderick D. Herdman, Stacey L. Handy
  • Patent number: 8187448
    Abstract: An electrodeposited crystalline functional chromium deposit which is nanogranular as deposited, and the deposit may be both TEM and XRD crystalline or may be TEM crystalline and XRD amorphous. In various embodiments, the deposit includes one or any combination of two or more of an alloy of chromium, carbon, nitrogen, oxygen and sulfur; a {111} preferred orientation; an average crystal grain cross-sectional area of less than about 500 nm2; and a lattice parameter of 2.8895+/?0.0025 A. A process and an electrodeposition bath for electrodepositing the nanogranular crystalline functional chromium deposit on a substrate, including providing the electrodeposition bath including trivalent chromium, a source of divalent sulfur, a carboxylic acid, a source of nitrogen and being substantially free of hexavalent chromium; immersing a substrate in the bath; and applying an electrical current to electrodeposit the deposit on the substrate.
    Type: Grant
    Filed: October 2, 2008
    Date of Patent: May 29, 2012
    Assignee: Atotech Deutschland GmbH
    Inventors: Agnes Rousseau, Craig V. Bishop
  • Patent number: 8110087
    Abstract: A method for producing a structured hard chromium layer, during which chromium from an electrolyte is deposited onto a workpiece, which contains: a) a Cr(VI) compound in a quantity corresponding to between 50 and 300 g/l of chromic anhydride; b) 0.5 g/l to 10 g/l sulfuric acid, and; c) 5 g/l to 15 g/l aliphatic sulfonic acid having 1 to 6 carbon atoms. The electrolyte comprises substantially no compounds from the group consisting of ammonium molybdate, alkaline molybdate, alkaline earth molybdate, ammonium vanadate, alkaline vanadate and alkaline earth vanadate, ammonium zirconate, alkaline zirconate and alkaline earth zirconate, and is processed with a cathodic efficiency of 12% or less. A method for producing a coating, to a structured hard chromium layer, a coating and an electrolyte.
    Type: Grant
    Filed: January 5, 2005
    Date of Patent: February 7, 2012
    Assignee: Federal-Mogul Burscheid GmbH
    Inventors: Rudolf Linde, Stefan Dürdoth, Wolfgang Stuckert
  • Publication number: 20110290658
    Abstract: The fluorine surfactant-free, long-term-stable and biodegradable additive for chromium electrolytes lowers the surface tension and hence improves the chromium deposition process, especially in the application for the electrolytical chromium-plating. Preferred additives are CH3(CH2)nSO3H and the salts thereof with n from 10 to 18. These additives are also useful as component in polymer mordants as pretreatments for polymer metallizations.
    Type: Application
    Filed: June 14, 2011
    Publication date: December 1, 2011
    Inventors: Lorenz LÄSER, Matthias Weiss, Frank Honselmann
  • Patent number: 7909978
    Abstract: A method of making an integrated circuit including a composition of matter for electrodepositing of chromium is disclosed. One embodiment provides a bath having a solution of a chromium salt in a substantially anhydrous organic solvent, to uses of certain chromium salts for electrodepositing and to processes for electrodepositing chromium.
    Type: Grant
    Filed: April 19, 2007
    Date of Patent: March 22, 2011
    Assignee: Infineon Technologies AG
    Inventors: Johannes Lodermeyer, Edmund Riedl, Werner Robl
  • Publication number: 20110062030
    Abstract: The electrolyte composition is used in a method of depositing metals, in particular, onto substrates, especially solar cells. The electrolyte composition is particularly suitable for the deposition of metals, in particular silver, onto solar cells. The electrolyte composition is preferably free of cyanides and contains at least one metal, preferably silver, and an iminodisuccinate derivative, preferably a sodium or postassium iminodisuccinate.
    Type: Application
    Filed: September 9, 2010
    Publication date: March 17, 2011
    Inventors: Lothar Lippert, Stefan Dauwe
  • Publication number: 20110065804
    Abstract: Articles having metallic finishes including antimicrobial agents dispersed throughout the finish and methods of electroplating said metallic finishes on a material. The metallic finishes include highly-decorative electroplated finishes for bathroom and kitchen hardware, door hardware, and other highly lustrous products where antimicrobial protection is preferred.
    Type: Application
    Filed: March 25, 2009
    Publication date: March 17, 2011
    Applicants: PAVCO INC., MICROBAN INTERNATIONAL LTD.
    Inventors: Leonard L. Diaddario, Matthew W. Stauffer
  • Patent number: 7699970
    Abstract: A method of producing a structured hard chrome layer is described, wherein chromium is deposited from an electrolyte onto a workpiece, said electrolyte containing: (a) a Cr (VI) compound in an amount corresponding to 50 g/l to 600 g/l of chromic acid anhydride (b) 0.5 g/l to 10 g/l of sulphuric acid; (c) 1 g/l to 20 g/l of aliphatic sulphonic acid, comprising 1 to 6 carbon atoms, and (d) 10 g/l to 200 g/l of at least one compound forming a dense cathode film, said compound being selected from among ammonium molybdate, alkali molybdate and alkaline earth molybdate, ammonium vanadate, alkali vanadate and alkaline earth vanadate, ammonium zirconate, alkali zirconate and alkaline earth zirconate. Further, the application relates to a structured hard chrome layer obtained according to said method and to an electrolyte for carrying out said method.
    Type: Grant
    Filed: September 18, 2003
    Date of Patent: April 20, 2010
    Assignee: Federal-Mogul Burscheid GmbH
    Inventors: Rudolf Linde, Stefan Durdoth
  • Publication number: 20100075174
    Abstract: The invention relates to a method for deposition of chromium layers as hard-chrome plating for protection against wear or corrosion and/or for decorative purposes and also an electroplating bath with which chromium layers of this type can be deposited. The invention also relates to hard-chrome surfaces produced accordingly.
    Type: Application
    Filed: July 31, 2007
    Publication date: March 25, 2010
    Applicant: Fraunhofer-Gesellschaft zur Forderung der angewandten Forschung e.V.
    Inventors: Jens Bohnet, Martin Metzner, Herwig Krassnitzer, Karl Schermanz
  • Publication number: 20090224422
    Abstract: Embodiments of a composite carbon nanotube structure comprising a number of carbon nanotubes disposed in a matrix comprised of a metal or a metal oxide. The composite carbon nanotube structures may be used as a thermal interface device in a packaged integrated circuit device.
    Type: Application
    Filed: January 9, 2009
    Publication date: September 10, 2009
    Inventor: Valery M. Dubin
  • Publication number: 20080187675
    Abstract: Disclosed herein arc novel liposome compositions generally including a foreign inclusion (e.g., diamond) component, and a liposome (e.g., i paucilamellar liposome) component. Also disclosed are methods of using these composition for plating and plate obtained thereby. Novel liposome compositions including components such as diamonds, are also disclosed, which can be used in a variety of applications, such as in abrasive, cosmetic or medical applications.
    Type: Application
    Filed: September 10, 2007
    Publication date: August 7, 2008
    Applicant: Frank C. Scarpa
    Inventors: Frank C. Scarpa, Dennis Johnson
  • Publication number: 20080142372
    Abstract: The fluorine surfactant-free, long-term-stable and biodegradable additive for chromium electrolytes lowers the surface tension and hence improves the chromium deposition process, especially in the application for the electrolytical chromium-plating. Preferred additives are CH3(CH2)nSO3H and the salts thereof with n from 10 to 18. These additives are also useful as component in polymer mordants as pretreatments for polymer metallizations.
    Type: Application
    Filed: September 4, 2007
    Publication date: June 19, 2008
    Inventors: Lorenz Laser, Matthias Weiss, Frank Honselmann
  • Patent number: 6911068
    Abstract: A metal plating bath containing organic compounds that inhibit or retard the consumption of plating bath additives. The additives are chemical compounds that improve the brightness of the plated metal, the physical properties of the plated metal especially with respect to ductility and the micro-throwing power as well as the macro-throwing power of the plating bath. The organic compounds that inhibit or retard the consumption of additives increases the life of the plating bath and improves the efficiency of the plating process. The plating baths containing the organic compounds that inhibit or retard additive consumption can be employed to copper, gold, silver, palladium, platinum, cobalt, cadmium, chromium, bismuth, indium, rhodium, ruthenium, and iridium.
    Type: Grant
    Filed: October 2, 2001
    Date of Patent: June 28, 2005
    Assignee: Shipley Company, L.L.C.
    Inventors: Andrew J. Cobley, Mark J. Kapeckas, Erik Reddington, Wade Sonnenberg, Leon R. Barstad, Thomas Buckley
  • Patent number: 6635166
    Abstract: Inorganic or organic fine particles which are insoluble to water are added to a metal plating bath, by dispersing the fine particles in a watery medium by the help of an azo-surfactant having an aromatic azo compound residue. Electrolysis is then carried out. According to the present invention, the content of the fine particles present in a composite plating film composed of the fine particles and a metal can be increased.
    Type: Grant
    Filed: December 4, 2001
    Date of Patent: October 21, 2003
    Assignee: Japan Science and Technology Corporation
    Inventors: Tetsuo Saji, Kumar Nabeen Shrestha
  • Publication number: 20030085132
    Abstract: A metal plating bath and metal plating process that contains aldehyde compounds that prevent or reduce the consumption of metal plating bath additives. The metal plating baths provide for an efficient plating method because the plating process need not be interrupted to replenish the plating bath with additives. The Metal plating baths may be employed to plate metals such as copper, gold, silver, palladium, cobalt, chromium, cadmium, bismuth, indium, rhodium, iridium, and ruthenium.
    Type: Application
    Filed: October 2, 2001
    Publication date: May 8, 2003
    Applicant: Shipley Company, L.L.C.
    Inventors: Andrew J. Cobley, Mark J. Kapeckas, Erik Reddington, Wade Sonnenberg, Leon R. Barstad, Thomas Buckley
  • Publication number: 20030066756
    Abstract: A metal plating bath and method for plating a metal on a substrate. The metal plating bath contains hydroxylamines that inhibit the consumption of additive bath components to improve the efficiency of metal plating processes. The additive bath components are added to metal plating baths to improve brightness of plated metal as well as the micro-throwing and macro-throwing power of the bath. In addition to brighteners, the additive bath components may include levelers, suppressors, hardeners, and the like. The hydroxylamines that inhibit additive consumption may be employed in metal plating baths for plating copper, gold, silver, platinum, palladium, cobalt, cadmium, nickel, bismuth, indium, tin, rhodium, iridium, ruthenium and alloys thereof.
    Type: Application
    Filed: October 4, 2001
    Publication date: April 10, 2003
    Applicant: Shipley Company, L.L.C.
    Inventors: David R. Gabe, Andrew J. Cobley, Leon R. Barstad, Mark J. Kapeckas, Erik Reddington, Wade Sonnenberg, Thomas Buckley
  • Patent number: 6447666
    Abstract: The present invention relates to a galvanic bath, to a process for the precipitation of chromium onto objects, and to the use of the process for the generation of textured hard-chrome layers on machine components. The galvanic bath contains in aqueous solution at least one compound delivering chromium(VI)-ions, and it comprises a) chromium(VI)-ions in an amount that corresponds to 100 to 600 g/ltr of chromic acid anhydride, b) sulfate ions in the form of sulfuric acid and/or of a soluble salt thereof in a molar concentration ratio of chromium(VI)-ions to sulfate ions (SO4−2) ranging from 90:1 to 120:1, and c) 2-hydroxyethane sulfonate ions in an amount that corresponds to 0.01 to 3.0 g/ltr of the sodium salt.
    Type: Grant
    Filed: March 7, 2001
    Date of Patent: September 10, 2002
    Assignee: MAN Roland Druckmashinen AG
    Inventor: Klaus Szameitat
  • Publication number: 20020014414
    Abstract: The use of alkali metal, alkaline earth metal, ammonium and substituted ammonium salts of alkyl and alkanol sulfonic acids as additives in pure metal and metal alloy sulfate electroplating baths has a number of unexpected benefits including wider useful current density range, improved appearance and in the case of tin improved oxidative stability. The metals and alloys include but are not limited to tin, nickel, copper, chromium, cadmium, iron, rhodium, ruthenium, iron/zinc and tin/zinc.
    Type: Application
    Filed: May 21, 2001
    Publication date: February 7, 2002
    Inventors: Hyman D. Gillman, Brenda Fernandes, Kazimierz Wikiel
  • Patent number: 6329071
    Abstract: Using a chrome plating bath containing organic sulfonic acid, plating is conducted by application of a pulse current to thereby form a crack-free lower chrome layer on a steel substrate. The lower chrome layer has a compressive residual stress of 100 MPa or more and a crystal grain size of from 9 nm to less than 16 nm. Subsequently, by application of a direct current, a cracked upper chrome layer is formed on the lower chrome layer, to thereby obtain a chrome plated part. The lower chrome layer imparts the chrome plated part with heat resistance and corrosion resistance, and the upper chrome layer imparts the chrome plated part with wear resistance and good sliding properties.
    Type: Grant
    Filed: November 2, 1999
    Date of Patent: December 11, 2001
    Assignee: Tokico Ltd.
    Inventors: Yuichi Kobayashi, Junichi Nagasawa, Shoichi Kamiya, Toshiyuki Fukaya, Hiromi Yamauchi, Kazuo Watanabe
  • Publication number: 20010009724
    Abstract: Deposition of metal in a preferred shape, including coatings on parts, or stand-alone materials, and subsequent heat treatment to provide improved mechanical properties. In particular, the method gives products with relatively high yield strength. The products often have relatively high elastic modulus, and are thermally stable, maintaining the high yield strength at temperatures considerably above 25° C. This technique involves depositing a material in the presence of a selected additive, and then subjecting the deposited material to a moderate heat treatment. This moderate heat treatment differs from other commonly employed “stress relief” heat treatments in using lower temperatures and/or shorter times, preferably just enough to reorganize the material to the new, desired form. Coating and heat treating a spring-shaped substrate provides a resilient, conductive contact useful for electronic applications.
    Type: Application
    Filed: January 29, 2001
    Publication date: July 26, 2001
    Inventors: Jimmy Kuo-Wei Chen, Benjamin N. Eldridge, Thomas H. Dozier, Junjye J. Yeh, Gayle J. Herman
  • Patent number: 6228244
    Abstract: C1-C12 Alkanesulfonic or Alkanedisulfonic compounds and Aminoalkanesulfonic acids or salts thereof, are used as additives in chromium plating baths to reduce anodic corrosion, improve the covering and penetrating power of the bath, reduce the surface-tension and give a bright deposit.
    Type: Grant
    Filed: December 18, 1998
    Date of Patent: May 8, 2001
    Assignee: Luigi Stoppani S.p.A.
    Inventors: Frediani Lido, Giovanni Merello
  • Patent number: 6183545
    Abstract: An aqueous solution for the reductive deposition of metals comprising, besides water, (A) a phosphine of the general formula (1)  in which R1, R2, and R3 denote lower alkyl groups, at least one of which being hydroxy-or amino-substituted lower alkyl group, and (B) a soluble compound of a metal or a compound of a metal solubilized through the formation of a soluble complex by said phosphine.
    Type: Grant
    Filed: June 28, 1999
    Date of Patent: February 6, 2001
    Assignee: Daiwa Fine Chemicals Co., Ltd.
    Inventors: Yoshiaki Okuhama, Takao Takeuchi, Masakazu Yoshimoto, Shigeru Takatani, Emiko Tanaka, Masayuki Nishino, Yuji Kato, Yasuhito Kohashi, Kyoko Kuba, Tetsuya Kondo, Keiji Shiomi, Keigo Obata, Mitsuo Komatsu, Hidemi Nawafune
  • Patent number: 5997714
    Abstract: The invention provides a material coated with an organic film which exhibits excellent corrosion resistance and lacquer adhesion. The invention includes an electroconductive substrate coated with an electrolytically polymerized coating film containing chromium. Particularly, a zinc-type plated steel sheet coated with an electrolytically polymerized coating film containing chromium in accordance with the invention is well suited for application in vehicle bodies. The invention further provides a method of making a material coated with an organic film which involves forming organic coating material containing chromium on an electroconductive substrate acting as an electrode by electrolytically polymerizing an organic monomer in an electrolyte solution containing chromium. The method provides a monolithic composite structure comprising chromium compounds and an organic coating film, and avoid the problems associated with passivation after chromium plating of steel.
    Type: Grant
    Filed: October 30, 1996
    Date of Patent: December 7, 1999
    Assignee: Kawasaki Steel Corporation
    Inventors: Kyoko Hamahara, Hisatada Nakakoji, Tomokatsu Katagiri, Shuichi Asahina, Kazuo Mochizuki
  • Patent number: 5453175
    Abstract: The present invention provides an improved method for electroplating chromium, using lead anodes, while achieving the advantages of using methanesulfonic acid without suffering the excessive anode-corrosion characteristics associated with that acid. Accordingly, chromium is electrodeposited from a bath containing chromic acid, sulfate ion and an alkylpolysulfonic acid containing from one to about three carbon atoms. The preferred alkylpolysulfonic acid is methanedisulfonic acid.
    Type: Grant
    Filed: June 30, 1994
    Date of Patent: September 26, 1995
    Assignee: Elf Atochem N. A., Inc.
    Inventor: Kenneth R. Newby
  • Patent number: 5415763
    Abstract: Methods for electrodepositing a chromium coating on a substrate comprising mmersing the substrate in an aqueous electrolyte, and passing a sufficient current through the electrolyte to effect deposition of a chromium coating on the substrate. The aqueous electrolytes comprise from about 0.2 to about 0.6 mol/l of trivalent chromium ions, greater than about 1.4 mol/l of an amidosulfonic acid or a salt thereof, ammonium ions, formic acid or a salt thereof, and water.
    Type: Grant
    Filed: August 18, 1993
    Date of Patent: May 16, 1995
    Assignee: The United States of America as represented by the Secretary of Commerce
    Inventors: Christian E. Johnson, David Lashmore, Elaine Soltani
  • Patent number: 5294326
    Abstract: Functional chromium and chromium-alloy deposits are obtained from an electroplating solution having substantially the composition: 22 g/l Cr.sup.+3 ; 250 g/l KCl; 63 g/l H.sub.3 BO.sub.3 ; 30 g/l HCO.sub.2.sup.= ; 15 g/lKBr; and 120 ppm of a wetting agent. The plating solution provides improved efficiency, stress values and appearance over the prior art, and is tolerant of metallic iron and ionic iron and ammonium.
    Type: Grant
    Filed: October 13, 1992
    Date of Patent: March 15, 1994
    Assignee: Elf Atochem North America, Inc.
    Inventor: George E. Shahin
  • Patent number: 5217599
    Abstract: Disclosed is a method for electroplating a metal sheet adapted for being used in electronic packaging material, such as printed circuit boards. Bismaleimide and its derivative are added into the plated solution so as to form insoluble particles of bismaleimide and its derivatives on the surface of the metal sheet. The resulting metal sheet is particularly adapted for being bonded to a polyimide film for the preparation of, for example, a printed circuit board. Also disclosed is a method of bonding the metal sheet of the present invention to a polyimide substrate. Precursor of polyimide are coated on the surface of the plate metal sheet and then thermal imidizing of the precursors takes place. No additional adhesives are needed for this bonding.
    Type: Grant
    Filed: November 8, 1991
    Date of Patent: June 8, 1993
    Assignee: Industrial Technology Research Institute
    Inventors: Ker-Ming Chen, Syh-Ming Ho, Tsung-Hsiung Wang, Richard P. Cheng, Aina Hung
  • Patent number: 5196109
    Abstract: An improved aqueous acidic trivalent chromium electrolyte and process for increasing the tolerance thereof to the presence of deleterious contaminating metal ions and organic impurities which normally progressively increase during commercial operation of the electrolyte ultimately resulting in chromium electrodeposits which are commercially unsatisfactory due to the presence of streaks, clouds, and hazes in the deposit. The improved composition contains an effective amount of at least one EDTA compound which is effective to mask the adverse effects of such contaminating metal and organic impurities and which also enhances the codeposition of such metal contaminants on the parts being plated thereby reducing, and in some instances, preventing the accumulation of such contaminating metal ions in the electrolyte.
    Type: Grant
    Filed: August 1, 1991
    Date of Patent: March 23, 1993
    Inventor: Geoffrey Scott
  • Patent number: 5196108
    Abstract: A method is shown for constructing portions of a sucker rod pump of the type having a steel plunger with an exterior cylindrical wall and a barrel with a cylindrical bore. A chromium case if formed on the cylindrical bore to a selected depth for receiving the plunger in sliding contact. The chromium case is formed by forming a base electrolyte bath including water, chromic acid, a sulfate component, an alkyl sulphonic acid, and an anion of molybdenum. The bore is then exposed to the aqueous electrolyte bath at a current density and at a plating temperature sufficient to form a chromium deposit of desired thickness on the bore.
    Type: Grant
    Filed: April 24, 1991
    Date of Patent: March 23, 1993
    Assignee: Scot Industries, Inc.
    Inventors: Thomas S. Wilmeth, Jesse L. Eades
  • Patent number: 5176813
    Abstract: The present invention provides a process for electroplating chromium using lead anodes while achieving the advantages of using methanesolfonic acid without suffering the excessive anode-corrosion characteristics associated with that acid. Accordingly, chromium is electrodeposited from a bath containing chromic acid, sulfate and an alkylpolysulfonic acid containing from one to about three carbon atoms. The invention also provides a plating process for chromium electrodeposition, a plating bath for use in the inventive process, and a replenishment composition for existing plating baths.
    Type: Grant
    Filed: November 5, 1990
    Date of Patent: January 5, 1993
    Assignee: Elf Atochem North America, Inc.
    Inventor: Kenneth R. Newby
  • Patent number: RE40386
    Abstract: Using a chrome plating bath containing organic sulfonic acid, plating is conducted by application of a pulse current to thereby form a crack-free lower chrome layer on a steel substrate. The lower chrome layer has a compressive residual stress of 100 MPa or more and a crystal grain size of from 9 nm to less than 16 nm. Subsequently, by application of a direct current, a cracked upper chrome layer is formed on the lower chrome layer, to thereby obtain a chrome plated part. The lower chrome layer imparts the chrome plated part with heat resistance and corrosion resistance, and the upper chrome layer imparts the chrome plated part with wear resistance and good sliding properties.
    Type: Grant
    Filed: March 31, 2003
    Date of Patent: June 17, 2008
    Assignee: Hitachi Ltd.
    Inventors: Yuichi Kobayashi, Junichi Nagasawa, Shoichi Kamiya, Toshiyuki Fukaya, Hiromi Hieno, Kazuo Watanabe