US3311548A - Electrodeposition of chromium - Google Patents
Electrodeposition of chromium Download PDFInfo
- Publication number
- US3311548A US3311548A US346095A US34609564A US3311548A US 3311548 A US3311548 A US 3311548A US 346095 A US346095 A US 346095A US 34609564 A US34609564 A US 34609564A US 3311548 A US3311548 A US 3311548A
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- United States
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- acid
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- chromium
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- sulfate
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/04—Electroplating: Baths therefor from solutions of chromium
- C25D3/10—Electroplating: Baths therefor from solutions of chromium characterised by the organic bath constituents used
Definitions
- This invention relates to improvements in the electrodeposition of chromium from aqueous acidic hexavalent chromium solutions. More particularly, it relates to the electrodeposition of chromium plate of improved covering power, which is accomplished by the use of certain aliphatic dicarboxylic acids as additives to acidic hexavalent chromium electroplating baths.
- the standard or conventional chromium bath employing only the sulfate anion as catalyst and used for plating on nickel, ferrous surfaces, yellow brass, or copper has been the 100 to 1 ratio of .chromic acid anhydride (CrO to sulfate ion.
- CrO to sulfate ion the 100 to 1 ratio of .chromic acid anhydride
- a 200 gram/liter chromic acid bath 2 grams per liter of sulfate ion would be used, and in a 400 grams/liter chromic acid bath, 4 grams/liter of sulfate ion would be used.
- the poorer will be the chromium coverage. If the sulfate ion is increased much beyond the 100 to 1 ratio, for example, to to 1 ratio of chromic acid to sulfate, then the chromium coverage gets poorer and poorer and finally with a large excess of sulfate ion no chromium plate is obtained, and merely trivalent chromium is formed at the cathode.
- the Formula A dicarboxylic acids without the sulfate anion do not make possible the electrodeposition of chromium from pure chromic acid solutions. However, in conjunction with small concentrations of sulfate anion they act as uncritical activators, that is, the sulfate anion is needed but only in optimum concentration for its catalytic effect and not for any special activating effect.
- carboxylic acids in acidic hexavalent chromium plating solutions, however, such carboxylic acids as acetic acid (or acetates) strongly attack the lead and lead alloy anodes that are used in chromic acid plating baths, and these anodes during use are corroded away at a rapid rate. This is also true for chloro acetic acids and trifiuoro acetic acid. Du Rose in US.
- the corrosive attack on the lead and lead alloy anodes by the Formula A dicarboxylic acids is no greater than that which occurs in the widely used chromium plating baths employing sulfate plus fluosilicate catalyst ions.
- Acetic acid, and the mono-, diand trichloroacetic acids and trifluoroacetic acids used in the same concentrations in the chromium plating bath as the Formula A dicarboxylic acids attack the lead and lead alloy anodes at least five times faster.
- Dicarboxylic acids such as tartaric, and phthalic acids are rapidly oxidized away by the chromic acid bath chromium ions formed at the cathode during the electrodeposition of the chromium metal. If most of this trivallent chromium is not re-oxidized, the chromium bath will become almost inoperative.
- the powerful oxidizing agent, lead dioxide forms on the anodes during electrolysis, and this oxidizing agent re-oxidizes the trivalent chromium to the hexavalent form.
- the acidic hexavalent chromium plating baths may be made up from straight chromic acid anhydride or chromic acid, and from mixtures with dichromates, chromates and polychromates. It is generally preferred to use straight chromic acid or chromic acid anhydride.
- the source of the sulfate ion may he sulfuric acid or one of its soluble salts, or from strontium sulfate in saturation concentrations, with or without added strontium ions from another source such as strontium chromate or dichromate or carbonate.
- baths of this invention may be modified by adding small concentrations of fluoride, fluosilicate, fluoborate, fluotitanate, fiuoaluminate or iluozirconate ions, or boric acid or saturated concentrations of thorium fluoride, thorium fluoborate or fiuozirconate, uranium tetrafluoborate, uranium tetrafluozirconate.
- organic activators such as, for example, trifluoromethyl sulfonic acid, or 2-hydroperfluoroethyl-l-phosphonic acid (HCF CF PO(OH) can be used together with the formula A dicarboxylic acids.
- ratios of chromic acid to sulfate of about 100 to 1 or 90 to 1 very little of these activators is needed but then the chromium coverage is not as great as when the ratio of chromic acid is about 300 to l or 200 to l, or 150 to 1.
- EXAMPLE I 200-400 grams/liter CrO 1-1.5 grams/liter S anion 3-8 grams/liter of succinic, adipic, or azelaic acid or sebacic acid 0-3 grams/liter perfluoro p-ethyl cyclohexyl sulfonic acid Temp. 40-55 C. (105-130 F.)
- EXAMPLE II 300-400 grams/liter CrO Saturation concentrations of SrSO (excess present) 0-50 grams/liter of strontium chromate 2-10 grams/liter of succinic, adipic, glutaric, or azelaic acid 0-30 grams/liter boric acid 0-5 grams/liter perfluoro p-ethyl cyclohexyl sulfonic acid (Instead of the strontium salts above, sulfuric acid or other source of sulfate anion can be used to give about 300 to 1 to about 140 to 1 ratio of chromic acid to sulfate.)
- EXAMPLE III 300-400 grams/liter CrO Saturation concentration of SrSO (excess present) Saturation concentration of ThF (excess present) Boric acid grams/liter to saturation 1-8 grams/liter of succinic, adipic, glutaric, azelaic or sebacic acid 0-5 grams/liter perfluoro p-ethyl cyclohexyl sulfonic acid
- EXAMPLE 1v 300-400 grams/ liter CrO Saturation concentration of SrSO (excess present) Saturation concentration of ThF; (excess present) 'Boric acid 10 grams/liter to saturation 1-8 grams/liter of adipic, glutaric, azelaic and sebacic acids, especially the last two are less soluble than succinic acid and appear to be more stable in the chromium plating bath.
- a method of electrodepositing chromium which comprises electrolyzing an aqueous acidic hexavalent chromium plating solution containing a ratio of CrO to sulfate ion greater than about 150 to 1 and less than about 400 to 1 and containing therein dissolved about 0.1 gram/liter to about 20 grams/ liter of a dicarboxylic acid characterized 'by the following formula HOOC- (CH -COOH said said said
- - dicarboxylic acid is adipic acid.
- dicarboxylic acid is azelaic acid.
- dicarboxylic acid is sebacic acid.
- said chromium plating solution is chromic acid in a concentration of about to about 500 grams/liter.
- a bath for the electrodeposition of chromium comprising an aqueous acidic hexavalent chromium plating solution containing a ratio of CrO to sulfate ion greater than about to 1 and less than about 400 to 1 and containing dissolved therein about 0.1 gram/liter to about 20 grams/liter of a dicarboxylic acid characterized by the following formula where x is an integer from 1 to 8 inclusive.
- a bath in accordance with claim 9 wherein said hexavalent chromium plating solution is chromic acid in a concentration of about 100 to about 500 grams/liter.
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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)
Description
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US346095A US3311548A (en) | 1964-02-20 | 1964-02-20 | Electrodeposition of chromium |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US346095A US3311548A (en) | 1964-02-20 | 1964-02-20 | Electrodeposition of chromium |
Publications (1)
Publication Number | Publication Date |
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US3311548A true US3311548A (en) | 1967-03-28 |
Family
ID=23357925
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US346095A Expired - Lifetime US3311548A (en) | 1964-02-20 | 1964-02-20 | Electrodeposition of chromium |
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Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3418221A (en) * | 1966-03-16 | 1968-12-24 | Corillium Corp | Chromium plating process |
US3475294A (en) * | 1964-10-08 | 1969-10-28 | M & T Chemicals Inc | Method of electroplating chromium and compositions therefor |
US3491566A (en) * | 1967-11-01 | 1970-01-27 | Carpenter L E Co | Method and apparatus for surface treatment of workpiece |
FR2043658A1 (en) * | 1969-05-26 | 1971-02-19 | M & T Chemicals Inc | |
US3627650A (en) * | 1969-07-15 | 1971-12-14 | Atomic Energy Commission | Method for producing a chromium-tungsten coating on tungsten for protection against oxidation at elevated temperatures |
US3725214A (en) * | 1971-02-19 | 1973-04-03 | Du Pont | Chromium plating medium for a portable plating device |
US4174265A (en) * | 1975-11-11 | 1979-11-13 | Tomoya Minegishi | Black chromium electroplating process |
US4588481A (en) * | 1985-03-26 | 1986-05-13 | M&T Chemicals Inc. | Chromium plating bath for producing non-iridescent, adherent, bright chromium deposits at high efficiencies and substantially free of cathodic low current density etching |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2063197A (en) * | 1933-08-30 | 1936-12-08 | Schneidewind Richard | Method of chromium plating |
US2517441A (en) * | 1945-07-09 | 1950-08-01 | Ductile Chrome Process Co | Electrodeposition of chromium |
US2640022A (en) * | 1950-11-07 | 1953-05-26 | United Chromium Inc | Composition, bath, and process for chromium plating |
US3129149A (en) * | 1961-05-08 | 1964-04-14 | M & T Chemicals Inc | Chromium plating process |
-
1964
- 1964-02-20 US US346095A patent/US3311548A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2063197A (en) * | 1933-08-30 | 1936-12-08 | Schneidewind Richard | Method of chromium plating |
US2517441A (en) * | 1945-07-09 | 1950-08-01 | Ductile Chrome Process Co | Electrodeposition of chromium |
US2640022A (en) * | 1950-11-07 | 1953-05-26 | United Chromium Inc | Composition, bath, and process for chromium plating |
US3129149A (en) * | 1961-05-08 | 1964-04-14 | M & T Chemicals Inc | Chromium plating process |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3475294A (en) * | 1964-10-08 | 1969-10-28 | M & T Chemicals Inc | Method of electroplating chromium and compositions therefor |
US3418221A (en) * | 1966-03-16 | 1968-12-24 | Corillium Corp | Chromium plating process |
US3491566A (en) * | 1967-11-01 | 1970-01-27 | Carpenter L E Co | Method and apparatus for surface treatment of workpiece |
FR2043658A1 (en) * | 1969-05-26 | 1971-02-19 | M & T Chemicals Inc | |
US3627650A (en) * | 1969-07-15 | 1971-12-14 | Atomic Energy Commission | Method for producing a chromium-tungsten coating on tungsten for protection against oxidation at elevated temperatures |
US3725214A (en) * | 1971-02-19 | 1973-04-03 | Du Pont | Chromium plating medium for a portable plating device |
US4174265A (en) * | 1975-11-11 | 1979-11-13 | Tomoya Minegishi | Black chromium electroplating process |
US4588481A (en) * | 1985-03-26 | 1986-05-13 | M&T Chemicals Inc. | Chromium plating bath for producing non-iridescent, adherent, bright chromium deposits at high efficiencies and substantially free of cathodic low current density etching |
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Legal Events
Date | Code | Title | Description |
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AS | Assignment |
Owner name: HOOKER CHEMICALS & PLASTICS CORP. Free format text: MERGER;ASSIGNOR:OXY METAL INDUSTRIES CORPORATION;REEL/FRAME:004075/0885 Effective date: 19801222 |
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AS | Assignment |
Owner name: OCCIDENTAL CHEMICAL CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:HOOKER CHEMICAS & PLASTICS CORP.;REEL/FRAME:004126/0054 Effective date: 19820330 |
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Owner name: OMI INTERNATIONAL CORPORATION, 21441 HOOVER ROAD, Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:OCCIDENTAL CHEMICAL CORPORATION;REEL/FRAME:004190/0827 Effective date: 19830915 |
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AS | Assignment |
Owner name: MANUFACTURERS HANOVER TRUST COMPANY, A CORP OF NY Free format text: SECURITY INTEREST;ASSIGNOR:INTERNATIONAL CORPORATION, A CORP OF DE;REEL/FRAME:004201/0733 Effective date: 19830930 |