EP4379095A1 - Dreiwertiges weisses chromplattierungsbad und dreiwertiges weisses chromplattierungsverfahren für ein zu plattierungsendes objekt damit - Google Patents

Dreiwertiges weisses chromplattierungsbad und dreiwertiges weisses chromplattierungsverfahren für ein zu plattierungsendes objekt damit Download PDF

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Publication number
EP4379095A1
EP4379095A1 EP22849467.0A EP22849467A EP4379095A1 EP 4379095 A1 EP4379095 A1 EP 4379095A1 EP 22849467 A EP22849467 A EP 22849467A EP 4379095 A1 EP4379095 A1 EP 4379095A1
Authority
EP
European Patent Office
Prior art keywords
trivalent chromium
plating bath
sub
chromium plating
white
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22849467.0A
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English (en)
French (fr)
Inventor
Madoka NAKAGAMI
Shun TSUJINO
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JCU Corp
Original Assignee
JCU Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by JCU Corp filed Critical JCU Corp
Publication of EP4379095A1 publication Critical patent/EP4379095A1/de
Pending legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00Electroplating: Baths therefor
    • C25D3/02Electroplating: Baths therefor from solutions
    • C25D3/04Electroplating: Baths therefor from solutions of chromium
    • C25D3/06Electroplating: Baths therefor from solutions of chromium from solutions of trivalent chromium
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00Electroplating: Baths therefor
    • C25D3/02Electroplating: Baths therefor from solutions
    • C25D3/04Electroplating: Baths therefor from solutions of chromium
    • C25D3/10Electroplating: Baths therefor from solutions of chromium characterised by the organic bath constituents used

Definitions

  • the present invention relates to a white trivalent chromium plating bath and a white trivalent chromium plating method for an object to be plated using the same.
  • Chromium plating is used as a coating film for decoration because it has a silver-white appearance.
  • Hexavalent chromium has been used for the chromium plating, but in recent years, since this hexavalent chromium affects the environment, its use has been restricted, and there has been a shift to a technique using trivalent chromium.
  • a chromium electroplating solution containing a water-soluble trivalent chromium salt, a complexing agent for trivalent chromium ions such as malic acid, a pH buffering compound, a sulfur-containing organic compound such as thiourea, and a water-soluble compound such as saccharin and having a pH of 2.8 to 4.2 is known (PTL 1).
  • the present applicant has developed a practical trivalent chromium plating bath in which the plating deposition rate is high (PTL 2: a trivalent chromium plating bath including a trivalent chromium compound, a complexing agent, potassium sulfate and ammonium sulfate as conductive salts, a pH buffering agent, and a sulfur-containing organic compound, in which a carboxylic acid having two or more hydroxy groups and two or more carboxy groups or a salt thereof is used as the complexing agent, and saccharin or a salt thereof and a sulfur-containing organic compound having an allyl group are used in combination as the sulfur-containing organic compounds), and an object of the present invention is to develop a plating technique, in which the composition is simpler than the trivalent chromium plating bath, and with which an appearance also suitable for decorative applications is obtained.
  • PTL 2 a trivalent chromium plating bath including a trivalent chromium compound, a complexing agent, potassium sulfate and
  • the present inventors conducted intensive studies to achieve the above-mentioned object, and as a result, they found that the above-mentioned object can be achieved by incorporating a sulfur-containing organic compound having a specific structure in a white trivalent chromium plating bath, and thus completed the invention.
  • the invention is directed to a white trivalent chromium plating method for an object to be plated, the method including electroplating the object to be plated in the white trivalent chromium plating bath.
  • the invention is directed to a method for improving a deposition rate of white trivalent chromium plating, the method including incorporating a sulfur-containing organic compound represented by the general formula (I) in a white trivalent chromium plating bath containing a trivalent chromium compound, a complexing agent, a sulfate serving as a conductive salt, and a pH buffering agent.
  • a sulfur-containing organic compound represented by the general formula (I) in a white trivalent chromium plating bath containing a trivalent chromium compound, a complexing agent, a sulfate serving as a conductive salt, and a pH buffering agent.
  • white trivalent chromium plating bath of the invention enables white trivalent chromium plating with a color tone and a deposition rate equivalent to those of hexavalent chromium plating.
  • the white trivalent chromium plating bath of the invention contains a trivalent chromium compound, a complexing agent, a sulfate as a conductive salt, a pH buffering agent, and a sulfur-containing organic compound.
  • sulfur-containing organic compound represented by the general formula (I) include thiazolidine, rhodanine, thiazolidin-2-one, 3-methylthiazolidine-2-thione, 4-thioxo-1,3-thiazolidin-2-one, 2-mercaptothiazoline (also known as 2-thiazoline-2-thiol), 2,4-thiazolidinedione, 3-methyl-1,3-thiazolane-2,4-dione, 3-aminorhodanine, 3-methylrhodanine, 3-ethylrhodanine, 3-allylrhodanine, rhodanine-3-acetic acid, and rhodanine-3-propionic acid, and among these, rhodanine, 2,4-thiazolidinedione, 3-aminorhodanine, and 3-ethylrhodanine are preferred.
  • these sulfur-containing organic compounds one type can be used, or two or more types can be used in combination.
  • the content of the sulfur-containing organic compound represented by the general formula (I) or the like in the plating bath of the invention is not particularly limited, but is, for example, 1 to 500 mg/L, and preferably 5 to 100 mg/L.
  • the trivalent chromium compound used in the plating bath of the invention is not particularly limited, but is, for example, basic chromium sulfate, chromium sulfate, chromium chloride, chromium sulfamate, or chromium acetate, and is preferably basic chromium sulfate or chromium sulfate.
  • these trivalent chromium compounds one type can be used, or two or more types can be used in combination.
  • the content of the trivalent chromium compound in the plating bath of the invention is not particularly limited, but is, for example, 1 to 25 g/L, and preferably 1 to 15 g/L in terms of metallic chromium.
  • the complexing agent used in the plating bath of the invention is not particularly limited, and examples thereof include dicarboxylic acids such as malic acid and tartaric acid, and salts of dicarboxylic acids such as sodium malate, sodium tartrate, and diammonium tartrate, and malic acid or diammonium tartrate is preferred. Among these complexing agents, one type can be used, or two or more types can be used in combination.
  • the content of the complexing agent in the plating bath of the invention is not particularly limited, but is, for example, 1 to 90 g/L, and preferably 2 to 50 g/L.
  • the conductive salt used in the plating bath of the invention is a sulfate such as potassium sulfate, ammonium sulfate, or sodium sulfate.
  • a sulfate such as potassium sulfate, ammonium sulfate, or sodium sulfate.
  • potassium sulfate is preferred.
  • these sulfates one type can be used, or two or more types can be used in combination.
  • the content of the sulfate in the plating bath of the invention is not particularly limited, but is, for example, 100 to 300 g/L, and preferably 120 to 240 g/L.
  • the pH buffering agent used in the plating bath of the invention is not particularly limited, and examples thereof include boric acid, sodium borate, potassium borate, phosphoric acid, and dipotassium hydrogen phosphate, and among these, boric acid and sodium borate are preferred. Among these pH buffering agents, one type can be used, or two or more types can be used in combination.
  • the content of the pH buffering agent in the plating bath of the invention is not particularly limited, but is, for example, 30 to 150 g/L, and preferably 50 to 110 g/L.
  • saccharin or a salt thereof in order to stabilize the deposition of chromium.
  • the saccharin or a salt thereof include saccharin and sodium saccharinate.
  • saccharin or a salt thereof one type can be used, or two or more types can be used in combination.
  • the content of saccharin or a salt thereof in the plating bath of the invention is not particularly limited, but is, for example, 0.5 to 10 g/L, and preferably 2 to 8 g/L. Naturally, the content of saccharin in the plating bath of the invention is not included in the content of the sulfur-containing organic compound represented by the general formula (I) or the like.
  • the plating bath of the invention in a preferred aspect may be, for example, a plating bath containing the above-mentioned components, but it goes without saying that it may be a plating bath containing only the above-mentioned components (a plating bath composed of the above-mentioned components).
  • the plating bath of the invention may further contain a polymer compound such as polyethylene glycol, ascorbic acid, sodium ascorbate, hydrogen peroxide, a surfactant, chloral hydrate, iminodiacetic acid, or the like as long as the effects of the invention are not impaired.
  • a polymer compound such as polyethylene glycol, ascorbic acid, sodium ascorbate, hydrogen peroxide, a surfactant, chloral hydrate, iminodiacetic acid, or the like as long as the effects of the invention are not impaired.
  • the pH of the plating bath of the invention is not particularly limited as long as it is acidic, and is preferably, for example, 2 to 4.5, and more preferably 3 to 4.5.
  • the method for preparing the plating bath of the invention is not particularly limited, and the plating bath can be prepared, for example, by adding and mixing a trivalent chromium compound, a complexing agent, a sulfate serving as a conductive salt, a pH buffering agent, and a sulfur-containing organic compound (saccharin or a salt thereof if necessary) in water at 50 to 60°C, and finally adjusting the pH with sulfuric acid, aqueous ammonia, or the like if necessary.
  • the plating bath of the invention enables white trivalent chromium plating on an object to be plated by electroplating the object to be plated in the plating bath of the invention in the same manner as in a conventional chromium plating bath.
  • Electroplating conditions are not particularly limited, but for example, electroplating may be performed at a bath temperature of 30 to 60°C using carbon or iridium oxide as an anode at a cathode current density of 2 to 20 A/dm 2 for 1 to 15 minutes.
  • Examples of the object to be plated that can be electroplated include metals such as iron, stainless steel, and brass, and resins such as ABS and PC/ABS.
  • the object to be plated may be subjected to a treatment such as copper plating or nickel plating in advance before being plated in the plating bath of the invention.
  • the deposition rate is 0.03 to 0.17 um/min, preferably 0.04 to 0.13 um/min, which is equal to or higher than the deposition rate when conventional hexavalent chromium plating is performed.
  • the deposition rate of white trivalent chromium plating can be improved by incorporating the sulfur-containing organic compound represented by the general formula (I) or the like in a white trivalent chromium plating bath containing a trivalent chromium compound, a complexing agent, a sulfate as a conductive salt, and a pH buffering agent.
  • a chromium-plated product thus obtained is white, and has an L* value of 80 or more, preferably 82 or more, more preferably 83 or more, and particularly preferably 83 to 84, as measured using a color difference meter, and the color tone is equivalent to that of hexavalent chromium plating.
  • the white chromium-plated product can be used for the same applications as conventional hexavalent chromium-plated products, but is particularly suitable for products for decorative applications such as cars, motorcycles, and metal fittings.
  • a trivalent chromium plating bath was prepared by dissolving the components shown in Table 1 in water and adjusting the pH with aqueous ammonia.
  • a Hull cell test was performed on the trivalent chromium plating bath using a nickel-plated brass plate. The Hull cell test conditions are as follows: current: 5 A; and plating time: 3 minutes. After plating, the film thickness of the brass plate was measured with X-ray fluorescence at a point where the current density is 10 A/dm 2 , and the deposition rate was calculated. Further, the appearance after plating was evaluated based on an L* value, an a* value, and a b* value obtained using a color difference meter (manufactured by Konica Minolta, Inc.).
  • the plating bath of the invention can be used for various applications in the same manner as white plating using hexavalent chromium.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
EP22849467.0A 2021-07-28 2022-07-26 Dreiwertiges weisses chromplattierungsbad und dreiwertiges weisses chromplattierungsverfahren für ein zu plattierungsendes objekt damit Pending EP4379095A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021122970A JP2023018744A (ja) 2021-07-28 2021-07-28 白色3価クロムめっき浴およびこれを利用した被めっき物への白色3価クロムめっき方法
PCT/JP2022/028711 WO2023008406A1 (ja) 2021-07-28 2022-07-26 白色3価クロムめっき浴およびこれを利用した被めっき物への白色3価クロムめっき方法

Publications (1)

Publication Number Publication Date
EP4379095A1 true EP4379095A1 (de) 2024-06-05

Family

ID=85087641

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22849467.0A Pending EP4379095A1 (de) 2021-07-28 2022-07-26 Dreiwertiges weisses chromplattierungsbad und dreiwertiges weisses chromplattierungsverfahren für ein zu plattierungsendes objekt damit

Country Status (4)

Country Link
EP (1) EP4379095A1 (de)
JP (1) JP2023018744A (de)
CN (1) CN117642528A (de)
WO (1) WO2023008406A1 (de)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2093861B (en) * 1981-02-09 1984-08-22 Canning Materials W Ltd Bath for electrodeposition of chromium
PL2217745T3 (pl) * 2007-10-02 2014-11-28 Atotech Deutschland Gmbh Krystaliczna powłoka ze stopu chromowego
US9765437B2 (en) * 2009-03-24 2017-09-19 Roderick D. Herdman Chromium alloy coating with enhanced resistance to corrosion in calcium chloride environments
BR122019020336B1 (pt) * 2011-05-03 2020-08-11 Atotech Deutschland Gmbh Banho de galvanização e método eletrodeposição de uma camada de cromo escuro em uma peça de trabalho
US11047064B2 (en) * 2013-01-10 2021-06-29 Coventya, Inc. Apparatus and method to maintaining trivalent chromium bath plating
EP3147388A1 (de) * 2015-09-25 2017-03-29 Enthone, Incorporated Flexible farbeinstellung für dunkle cr(iii)-plattierungen
EP3725920A4 (de) * 2017-12-13 2021-04-21 JCU Corporation Dreiwertige chrombeschichtungslösung und verfahren zum verchromen unter verwendung derselben
EP3819404A4 (de) * 2018-07-03 2022-02-09 JCU Corporation Dreiwertige chromplattierungslösung und chrombeschichtungsverfahren damit

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JP2023018744A (ja) 2023-02-09
CN117642528A (zh) 2024-03-01
WO2023008406A1 (ja) 2023-02-02

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