EP4051829A1 - Verfahren zur dekorativen plattierung mit sulfatbasiertem, ammoniumfreiem trivalentem chrom - Google Patents

Verfahren zur dekorativen plattierung mit sulfatbasiertem, ammoniumfreiem trivalentem chrom

Info

Publication number
EP4051829A1
EP4051829A1 EP20796851.2A EP20796851A EP4051829A1 EP 4051829 A1 EP4051829 A1 EP 4051829A1 EP 20796851 A EP20796851 A EP 20796851A EP 4051829 A1 EP4051829 A1 EP 4051829A1
Authority
EP
European Patent Office
Prior art keywords
bath
ions
acid
chromium
group
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
EP20796851.2A
Other languages
English (en)
French (fr)
Inventor
Diego DAL ZILIO
Andrea Martin
Sandrine Dalbin
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.)
Coventya Srl
Original Assignee
Coventya SpA
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
Priority claimed from EP20154909.4A external-priority patent/EP3859053A1/de
Application filed by Coventya SpA filed Critical Coventya SpA
Publication of EP4051829A1 publication Critical patent/EP4051829A1/de
Pending legal-status Critical Current

Links

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
    • C25D17/00Constructional parts, or assemblies thereof, of cells for electrolytic coating
    • C25D17/10Electrodes, e.g. composition, counter electrode
    • 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
    • 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
    • C25D3/56Electroplating: Baths therefor from solutions of alloys
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/627Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25DPROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D9/00Electrolytic coating other than with metals
    • C25D9/04Electrolytic coating other than with metals with inorganic materials
    • C25D9/08Electrolytic coating other than with metals with inorganic materials by cathodic processes

Definitions

  • the present invention refers to an electroplating bath for electroplating a chro- mium or chromium alloy layer, the bath comprising trivalent chromium ions, organic carboxylic acid, sulfate ions, sodium conductive ions, and additives in the form of inorganic sulfur compound and boric acid as well as a process using such an electroplating bath.
  • Chrome deposits from trivalent chrome electrolytes are widely used in the in- dustry due to their unique properties they allow substrates to work longer and under tougher conditions that they would normally survive in.
  • Decorative chrome plating is designed to be aesthetically pleasing and durable. Thicknesses range from 0.05 to 0.5 ⁇ m, however they are usually between 0.13 and 0.25 ⁇ m. Decorative chrome plating is also very corrosion resistant and is often used on car parts, tools and kitchen utensils.
  • hexavalent chrome deposits were featuring a blue-white appearance that is distinguishing from the trivalent chrome deposits. This colour is still very appreciated by customers that are used to hexavalent chrome products.
  • JP2009035806 describes a trivalent chromium plating bath and a method for producing a chromium plating.
  • This plating bath contains (1) complex solution of trivalent chromium obtained by maintaining under heating at least 1 type of component chosen from group which consists of aqueous solution aliphatic car- boxylic acid and its salt, and aqueous solution containing trivalent chrome com- pound, (2) conductive salt (3) buffer for pH, and (4) at least 1 type of sulfur- containing compound chosen from the group having an S02 group.
  • the draw- back of such a plating solution is the use of a sulfur-containing organic com- pound instead of inorganic one and they do not use iron in the plating bath.
  • JP2010189673 describes novel trivalent chromium plating bath capable of forming a trivalent chromium plating film having better corrosion resistance as compared with the prior art.
  • a trivalent chromium plating bath comprising an aqueous solution containing a water-soluble trivalent chromium compound, a conductive salt, a pH buffer, a sulfur-containing compound and an aminocar- boxylic acid.
  • the drawback of such a plating bath is the lack of sodium and iron ions in the plating bath which will not get the desired color.
  • WO2019117178 describes a trivalent chromium plating solution containing: a trivalent chromium compound; a complexing agent; potassium sulfate and am- monium sulfate as conductive salts; a pH buffer; and a sulfur-containing organic compound.
  • the trivalent chromium plating solution is practical and has a high plating deposition rate.
  • the drawback of such a plating solution is the use of a sulfur-containing organic compound instead of inorganic one and they do not use iron in the plating bath.
  • EP2411567 describes a chromium electroplating solution comprising a chro- mium electroplating solution comprising: (1) a water soluble trivalent chro- mium salt; (2) at least one complexant for trivalent chromium ions; (3) a source of hydrogen ions sufficient to create a pH of from 2.8-4.2; (4) a pH buffering compound; and (5) a sulfur-containing organic compound.
  • the chromium elec- troplating solution is usable in a method for producing an adherent metallic coating on a decorative article, such coating having enhanced resistance to cor- rosion in environments containing calcium chloride.
  • the drawback of such a solution is the use of a sulfur-containing organic compound instead of inorganic one and the absence of iron ions in the solution.
  • an electroplating bath for depositing a chromium or chromium alloy layer which comprises a) at least one source of trivalent chromium ions, b) at least one source of sulfate ions, c) at least one organic acid as a complexing agent, d) sodium saccharin, e) at least one polyalkylene glycol, f) sodium vinyl sulfonate, g) at least one inorganic sulfur compound, h) at least one pH buffer, and, optionally, i) at least one source of ferric or ferrous ions.
  • the sulfate based trivalent chromium ions bath allows to obtain a whiter colour of the plating opposed to chloride based bath that get a darker plating with a higher carbon percentage.
  • the choice of the sodium is preferred to increase the whiteness of the plat- ing.
  • the use of ferric or ferrous ions also increase the corrosion resistance per- mitting to pass the PV1073 A test.
  • the combination of ferric, sodium and sulfate ions permit to obtain a blue and white colour close to those from hexavalent chrome deposits.
  • an inorganic sulfur such as an oxyacid anion containing sulfur having the valence lower than 6 is preferred.
  • the at least one organic acid is selected from the group of dicarboxylic acids, preferably selected from the group consisting of malic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, and mixtures thereof.
  • malic acid preferably selected from the group consisting of malic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, and mixtures thereof.
  • succinic acid preferably selected from the group consisting of malic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, and mixtures thereof.
  • succinic acid preferably selected from the group consisting of malic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, and mixtures thereof.
  • adipic acid preferably selected from the group consisting of malic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, and mixtures thereof.
  • malic acid
  • the concentration of the at least one organic acid is from 5 to 40 g/L, preferably from 10 to 30 g/L, more preferably from 15 to 25 g/L.
  • the concentration of the at least one trivalent chro- mium ion is from 5 to 25 g/L, preferably from 8 to 20 g/L.
  • the concentration of the sulfate ions from at least one source of sulfate ions is from 150 to 300 g/L, preferably from 180 to 280 g/L, more preferably from 200 to 250 g/L.
  • the source of trivalent chromium ions is chro- mium(lll) sulphate in acidic or basic form.
  • the at least one inorganic sulfur compound is selected from the group of oxyacid anions comprising sulfur having a valence lower than 6, preferably selected from the group consisting of:
  • the concentration of the at least one inorganic sul- fur compound is from 5 to 500 mg/L, preferably from 10 to 200 mg/L.
  • the electroplating bath can comprise at least one source of ferric or ferrous ions.
  • concentration of the ferric or ferrous ions from at least one source of ferric or ferrous ions is preferably from 20 to 200 mg/L, more preferably from 30 to 150 mg/L, and even more preferably from 40 to 100 mg/L.
  • the concentration of the at least one pH buffer is in a range from 50 to 120 g/L, preferably from 60 to 110 g/L, more preferably from 80 to 100 g/L.
  • a pH buffer it is preferred to use at least one of the group boric acid, citric acid, succinic acid, lactic acid, tartaric acid, and mixtures thereof. Particular pre- ferred is the use of boric acid as pH buffer.
  • the pH of the bath is preferably in the range from 1 to 5, more preferably from 2 to 4, and even more preferably from 3.1 to 3.9.
  • the concentration of the sodium vinyl sulfonate is preferably from 0.1 to 5 g/L, more preferably from 0.2 to 3 g/L.
  • the bath is (substantially) free of at least one of chloride ions, ammonium ions, amino carboxylic acid ions and hexavalent chromium ions. In particular, it is preferred that some or all of these ions are absent.
  • the concentration of sodium saccharin is from 0.1 to 10 g/L, and more preferably from 1 to 5 g/L.
  • the at least one polyalkylene glycol has a molecular weight of lower than 2000 g/mol and is preferably selected from the group consisting of:
  • the advantage of having at least one polyalkylene glycol, especially at least one polyalkylene glycol with a molecular weight of lower than 2000 g/mol, in the bath is that thicknesses of the deposits which are obtainable with the bath are higher than with baths that do not contain said polyalkylene glycol.
  • the concentration of the at least one polyalkylene glycol is from 1 to 15 g/L, preferably from 5 to 10 g/L.
  • a preferred embodiment of the electroplating bath for depositing a chromium or chromium alloy layer comprises: a) 5 to 25 g/L of trivalent chromium ions from at least one source of chro- mium ions, b) 150 to 300 g/L of sulfate ions from at least one source of sulfate ions, c) 5 to 40 g/L of at least one organic acid as a complexing agent, d) 0.1 to 10 g/L of sodium saccharin, e) 1 to 15 g/L of at least one polyalkylene glycol, f) 0.1 to 5 g/L of sodium vinyl sulfonate, g) 5 to 500 mg/L of at least one inorganic sulfur compound, h) 50 to 120 g/L of at least one pH buffer, and, optionally, i) 20 to 200 mg/L of ferric or ferrous ions from at least one source of fer- ric or ferrous ions.
  • a method for preparing an electroplated product by electroplating a substrate comprising the following steps:
  • A) providing an electroplating bath comprising : a) at least one source of trivalent chromium ions, b) at least one source of sulfate ions, c) at least one organic acid as a complexing agent, d) sodium saccharin, e) at least one polyalkylene glycol, f) sodium vinyl sulfonate, g) at least one inorganic sulfur compound, h) at least one pH buffer, and, optionally, i) at least one source of ferric or ferrous ions;
  • the cathode current density is in a range from B to 14 A/dm 2 , preferably from 5 to 10, and/or the anode current density is in a range from 4 to 12 A/dm 2 , preferably from 5 to 10 A/dm 2 .
  • the anodes consist of a mixed metal oxide, preferably a mixed metal oxide selected from the group consisting of mixed metal oxides of at least two of platinum, ruthenium, iridium and tantalum, more preferably mixed metal oxides of iridium and tantalum.
  • the deposition rate during step C) is from 0.01 to 0.5 ⁇ m/min, preferably from 0.02 to 0.3 ⁇ m/min, and more preferably from 0.03 to 0.2 ⁇ m/min.
  • step C) is conducted at a temperature from 35 to 60°C, pref- erably from 40 to 58°C, more preferably from 45 to 55°C.
  • the alloy obtainable from this method com- prises or consists of carbon, sulphur, oxygen, chrome and, optionally, iron.
  • the alloy has a colour measured by L, a, b values from 80 to 86, -0.8 to 0, -1.5 to 1.0.
  • the L, a, b values are from 80 to 86, -0.8 to 0, -0.8 to 1.
  • the L, a, b values are from 83 to 85, -0.7 to -0.4, -0.5 to 0.2.
  • the percentage of carbon in the alloy is preferably from 1 to 5 atomic % (at%), more preferably from 2 to 4 at%.
  • the alloy preferably comprises from 0,5 to 4 at%, more preferably from 1 to 3 at% sulfur.
  • the alloy preferably comprises from 1 to 5 at%, preferably from 2 to 4 at% of oxygen.
  • the alloy preferably comprises from 0 to 12 at% of iron.
  • the percentage of iron in the alloy is from 3 to 12 at%, preferably from 5 to 10 at%.
  • the alloy preferably com- prises from 74 to 94.5 at%, more preferably from 79 to 90 at%, chrome.
  • the atomic % (at%) of the alloy can be determined by optical emission spectroscopy (OES).
  • Fig.l shows the chromium coverage on a Hull cell panel with the three points (HCD, MCD, LCD) used for the examples.
  • the panels were evaluated: the thickness of Chromium using the X-Ray method EN ISO 3497 in three points 1cm from the left edge define as HCD (High Current Density), 5 cm from the left edge define as MCD (Medium Current Density), 7 cm from the left edge defined as LCD (Low Current Density).
  • the colour at the point defined as MCD was measured by a Colorimeter KONICA MINOLTA CM2600 defining the colour as CIELAB (L, a, b).
  • Chromium deposit coverage measuring the mm from the left edge to the maximum coverage of the deposit to the right.
  • Chromium deposit was tested to the PV1073 A that is an auto- motive standard used to evaluate the corrosion performance of Chromium de- posit to the Calcium Chloride.
  • the present invention refers to the alloy carried out with the example n°6 char- acterized in that the alloy composition contains 5-10 at % of Fe, 1-3 at % of S, 2-4 at % of C, 2-4 at % of O, remaining at % Cr (up to 100 at %) and reaching a comparable color to the reference example and a good deposition rate, with the features of claim 1 and the method for preparing an electroplated product by using the electroplating bath with the features of claim 10.
  • the bath did not contain Methyl Polyethylen Glycol (Mw 500).
  • Mw 500 Methyl Polyethylen Glycol
  • the disadvantage of omitting said compound in the bath is that the ob- tained thickness at HCD is much lower than with the bath according to the in- vention (bath n°6).
  • the oxyacid sul- phuranion anion of sodium dithionite
  • alone is not able to increase the com- pliance regarding the color, the coverage and the PV 1073A.
  • the bath did not contain an oxyacid sulphur anion, i.e. did not contain sodium dithionite in the present case.
  • the disadvantage of omitting said compound in the bath is that the thicknesses at HCD, MCD and LCD are much lower than with the bath according to the invention (bath n°6). Color, coverage and PV 1073A are complying.
  • the example n°6b shows a similar results to the n°6 but with the better colour performance. In particular the b value reaches a very close value to the refer- ence CrVI, wherein the efficiency is just a little bit, i.e. not significantly, reduced.

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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)
  • Inorganic Chemistry (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
  • Electroplating Methods And Accessories (AREA)
EP20796851.2A 2019-10-31 2020-10-30 Verfahren zur dekorativen plattierung mit sulfatbasiertem, ammoniumfreiem trivalentem chrom Pending EP4051829A1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP19206651 2019-10-31
EP20154909.4A EP3859053A1 (de) 2020-01-31 2020-01-31 Verfahren zur dekorativen plattierung mit sulfatbasiertem, ammoniumfreiem trivalentem chrom
PCT/EP2020/080584 WO2021084103A1 (en) 2019-10-31 2020-10-30 Sulfate based, ammonium free trivalent chromium decorative plating process

Publications (1)

Publication Number Publication Date
EP4051829A1 true EP4051829A1 (de) 2022-09-07

Family

ID=73013463

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20796851.2A Pending EP4051829A1 (de) 2019-10-31 2020-10-30 Verfahren zur dekorativen plattierung mit sulfatbasiertem, ammoniumfreiem trivalentem chrom

Country Status (8)

Country Link
US (1) US20220403538A1 (de)
EP (1) EP4051829A1 (de)
JP (1) JP7342253B2 (de)
KR (1) KR20220119012A (de)
CN (1) CN114729463A (de)
CA (1) CA3155524C (de)
MX (1) MX2022004290A (de)
WO (1) WO2021084103A1 (de)

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2109817B (en) * 1981-11-18 1985-07-03 Ibm Electrodeposition of chromium
GB8503019D0 (en) * 1985-02-06 1985-03-06 Canning W Materials Ltd Electroplating
US5196109A (en) * 1991-08-01 1993-03-23 Geoffrey Scott Trivalent chromium electrolytes and plating processes employing same
KR100572486B1 (ko) * 2003-11-29 2006-04-19 테크앤라이프 주식회사 3가 크롬도금액 조성물과 그 제조방법
WO2006043507A1 (ja) * 2004-10-18 2006-04-27 Yamaha Hatsudoki Kabushiki Kaisha エンジン用部品
KR100858711B1 (ko) * 2007-03-30 2008-09-17 한국기계연구원 3가크롬 도금액
JP5322083B2 (ja) 2007-07-12 2013-10-23 奥野製薬工業株式会社 3価クロムめっき浴及びその製造方法
JP5652585B2 (ja) 2009-02-16 2015-01-14 奥野製薬工業株式会社 3価クロムめっき浴
US9765437B2 (en) 2009-03-24 2017-09-19 Roderick D. Herdman Chromium alloy coating with enhanced resistance to corrosion in calcium chloride environments
CN105671599A (zh) * 2016-04-11 2016-06-15 济南德锡科技有限公司 一种硫酸盐三价铬电镀液及其制备方法
CN106086949B (zh) * 2016-08-26 2019-01-18 武汉迪赛环保新材料股份有限公司 一种三价铬电镀液及电镀方法
EP3299497A1 (de) * 2016-09-27 2018-03-28 ATOTECH Deutschland GmbH Verfahren zur behandlung einer chromoberfläche
JP6951465B2 (ja) 2017-12-13 2021-10-20 株式会社Jcu 3価クロムメッキ液およびこれを用いたクロムメッキ方法
WO2020009096A1 (ja) * 2018-07-03 2020-01-09 株式会社Jcu 3価クロムメッキ液およびこれを用いたクロムメッキ方法

Also Published As

Publication number Publication date
KR20220119012A (ko) 2022-08-26
JP7342253B2 (ja) 2023-09-11
WO2021084103A1 (en) 2021-05-06
CA3155524A1 (en) 2021-05-06
MX2022004290A (es) 2022-05-10
CN114729463A (zh) 2022-07-08
JP2022551461A (ja) 2022-12-09
CA3155524C (en) 2024-02-27
US20220403538A1 (en) 2022-12-22

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