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US3006823A - Plating bath and process - Google Patents

Plating bath and process Download PDF

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Publication number
US3006823A
US3006823A US844876A US84487659A US3006823A US 3006823 A US3006823 A US 3006823A US 844876 A US844876 A US 844876A US 84487659 A US84487659 A US 84487659A US 3006823 A US3006823 A US 3006823A
Authority
US
United States
Prior art keywords
bath
chromium
plating
acid
gram
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.)
Expired - Lifetime
Application number
US844876A
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English (en)
Inventor
Alden J Deyrup
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.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
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 to DENDAT1247803D priority Critical patent/DE1247803C2/de
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Priority to US844876A priority patent/US3006823A/en
Priority to US47139A priority patent/US3021267A/en
Priority to FR840489A priority patent/FR1275069A/fr
Priority to DEP36210A priority patent/DE1245678B/de
Priority to GB34491/60A priority patent/GB965684A/en
Priority to GB44440/63A priority patent/GB965685A/en
Priority to DEP36209A priority patent/DE1245677B/de
Priority to DEP25807A priority patent/DE1247803B/de
Application granted granted Critical
Publication of US3006823A publication Critical patent/US3006823A/en
Priority to US388755A priority patent/US3203876A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D1/00—Electroforming
    • C25D1/04—Wires; Strips; Foils
    • 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 chromium plating, and more particularly it relates to chromium plating from a new and improved electrolytic plating bath.
  • the present commercial chromium plating processes are based on the electrolysis of chromium trioxide, CrO (chromic acid) solutions containing small amounts of a catalyst, e.g., sulfates, fluorides or the like.
  • a catalyst e.g., sulfates, fluorides or the like.
  • the current density and temperature during plating must be closely controlled. Even when closely controlling the current density, temperature and chromic acid-catalyst ratio, the throwing power of the plating bath is very low as compared to other metal plating processes. Because of poor throwing power, it is necessary to provide anodes conforming to the shape of the object to be plated.
  • the current eificiency of the commercial plating baths is usually no greater than 812% and under the most optimum conditions only to Also, objectionably large volumes of oxygen and hydrogen are given ofi during plating as a result of which a highly noxious and corrosive spray of chromic acid is always present over the plating bath during the plating operation. Again, large amounts of chromic acid are lost by drag-out and spray due to the necessity of employing rather highly concentrated amounts of chromic acid in commercial baths.
  • Another object is to provide a new and improved plating process in which chromium is plated from a plating bath containing chromium in trivalent form and which will exhibit good current efiiciency and throwing power and will produce excellent bright chromium plate.
  • the above objects may be accomplished, in general, by preparing an electrolytic aqueous chromium plating bath comprising chromic carboxylate, a carboxylic acid and boric acid.
  • the chromic carboxylate and the carboxylic acid, and possibly other bath constitutents appear to be present, to a considerable extent, in the form of a combined complex chemical structure in which chromium has the valence of three.
  • the bath should have a pH value between 1.5 and 3.0.
  • a chromium plating bath and process is described and claimed in which the aqueous electrolytic chromium plating bath comprises a chromic carboxylate, sodium carboxylate, a carboxylic acid, sodium fluoride and boric acid, and in which the pH is between 3.5 and 4.5.
  • the bath of this invention (litters from the Berzins bath only in the preferred exclusion of a fluoride, the presence of little or no alkali carboxylate, and a different pH, it appears that the complex compounds present in the two baths differ greatly from each other. This is evidenced by the fact that the pH Value of 3.5 to 4.5 of the Berzins bath will produce exceedingly poor or no plating whatever if employed in this bath and vice versa if the pH value of 1.5 to 3.0 of this bath is employed in the Berzins bath no useful plating can be accomplished. Moreover, the bath of this invention excels outstandingly the Berzins bath in the working range which can be attained with good current efliciency.
  • the electrolytic plating bath of this invention may be operated electrolytically at room temperature or temperatures as high as 65 C. to deposit bright, continuous, highly corrosion-resistant chromium plate.
  • the metallic surface to be plated is first thoroughly cleaned in accordance with cleaning procedures well established in the art.
  • the metallic surface to be plated for example, copper, copper alloys, bronze, brass or nickel surface is smooth and polished so as to produce a bright chromium plated finish.
  • the metallic object to be plated is suspended as the cathode in the aforesaid electrolytic bath and spaced fairly evenly from an inert anode, such as a carbon, graphite, platinum or platinized titanium anode.
  • the plating may be carried out by passing an electric current of 25 to 200 amperes per square foot between said cathode and anode.
  • the plating baths of this invention are greatly superior to commercial hexavalent chromium plating baths in current efiiciency, throwing power and plating range. These terms are, for convenience, defined as follows:
  • Current efiiciency is generally defined as the ratio of weight of metal actually deposited by a given current for a given time to that which would have been deposited if electro-reduction of the desired metal were eflicient. The latter is calculated from Faradays law, which says that 96,500 coulombs (ampere-seconds) is required to electrodeposit one gram equivalent of metal, if no side-reactions occur such as liberation of hydrogen. Current efliciency is commonly expressed as percent. It is important to note that current eiiiciencies as thus calculated are not directly comparable between VI, III, and l'I-valent chromium.
  • Throwing power is a term used in the plating industry to signify the degree to which plating occurs in recesses or on surfaces which are remote from the anode as compared with plating on flat surfaces or those near of each specific bath the plating is burned or discolored, matt, spongy, or otherwise defective. Between these limits, which I will call threshold current density and ceiliug'current density, good plating occurs. It is evident that if this range is very narrow, the system will have poor throwing power. This is a present handicap in commercial chromium plating. 'It is also evident that'if this range is very broad and the ceiling current density occurs at very heavy currents, then plating can be very rapid, even if current efficiency is only moderately good.
  • Chromic carboxylate of the bath may be the chromic salt of a carboxylic acid, for example, the chromic salt of glycolic,'lactic, formic or oxalic acids or mixtures thereof.
  • the preferred chromic carboxylates are chromic salts of alpha-hydroxy carboxylic acids for example, glycolic and lactic acids, the cromic glycolate having given the best results.
  • These carboxylates may be added to the platingbath as such or they may be formed in the bath by dissolving chromic hydroxide or carbonate or even metallic chromium in the carboxylic acid and the pH adjustedwith sodium hydroxide or carbonate.
  • a convenient way of preparing the chromic carboxylates is based on the reduction of chromic acid (CrO with the carboxylic acid, for example, glycolic acid, in accordance with the equation:
  • the glycolic to chromic ion ratio is maintained between 1.1 to 1 and 2.1 to 1.
  • the threshold current density increases undesirably.
  • Large amounts of unionized glycolic acid or other acids (even at unchanged pH) undesirably raise the threshold current density. I believe this is caused by a competing useless reaction jat'the cathode which liberates hydrogen from the unionized acid.
  • the excess glycolic acid (over a ratio of 1 glycolic to l chromium) should be small. If maximum current efliciency is desired, this ratio may be somewhat increased in therange specified. -Some satisfactory plates have been obtained when the carboxylic acid is formic or oxalic, or mixtures of these with glycolic acid. The properties of these plating systems are inferior to those containing only glycolic acid, either in current efliciency or plating range or brilliance of plate.
  • the concentration of chromium in the plating bath is suitably 0.5, 1, or 1.5 moles per liter. Results do not depend very critically on concentration.
  • the concentration of carboxylic acid is specified by this and the ratio .cited above.
  • the bath of the present process contains smaller amounts.
  • free glycolate ion cannot exceed 0.04 mole per liter, as calculated from the dissociation constant of glycolic acid at 25 C.:
  • the boric acid may be added as borax, boron oxide, or boric acid. Without the presence of boric acid, bright chromium plating can be obtained only within an impractically narrow range of current densities. Boric acid expands this range tremendously. It is preferred to use it at as high a concentration as possible within the limit 01 solubility; that is, about one mole per liter.
  • the plating bath of this invention needs the addition of an alkali metal salt of a strong acid.
  • the water solution of the chromium complex formed in this bath has a .very low electric conductivity.
  • the alkali metal salt of a strong acid is necessary to furnish the conductivity required for practical electroplating.
  • the cation of the aforesaid salt can be sodium or potassium, the latter being preferred for higher conductivity.
  • the strong acid anions should be anions that are not reduced at the cathode during the electroplating operation.
  • some of the above-mentioned anions cause problems at the anode.
  • chloride ions liberate noxious chlorine at the anode, or in the case of perchlorate ions, the chromium complex may be oxidized electrically at the anode to hexavalent chromium which is detrimental to plating performance.
  • These difliculties may be partly avoided by placing the anode in a separate compartment with aporous diaphragm to limit mixing of the solution from the anode and cathode regions. These difliculties may be completely avoided by isolating the anode within a cation-permeable membrane.
  • the above-named constituents of the electrolytic plating bath of this invention are preferably present in certain proportions. In 1000 grams of plating solution, it is preferred that the several constituents be present in about the following number of gram-moles depending, of course, upon the particular compounds used, it being understood that the constituents may be present as complex chemical combinations, and reference to amounts of the following specific compounds is to be regarded from a standpoint of equivalence
  • the chromium plating bath of this invention is maintained at a pH between 1.5-3.0 and preferably between 2.0-2.7. If the pH is reduced, the threshold curient density increases. This may be undesirable if carried too far. However, plating efficiency and plating range generally increase somewhat. If pH is raised, the reverse efiects occur. There is no single pH at which all plating may be carried out at best results; however, in general, when the pH reaches 3.5 nearly all plating ceases.
  • acids having a dissociation constant of between about and 10* and their salts other than the carboxylic acids specified in amounts to be present at a ratio to chromic ion of 0.7 to 1 to 3 to 1, or preferably 1.1 to l to 2.1 to 1.
  • Such acids and salts appear to raise the threshold current density at which the bath may be used to obtain bright plates.
  • one mole of chromic acid may, for example, be reacted with 1.6 moles of glycolic acid.
  • 0.5 mole of glycolic acid is needed, 1.0 mole is present to form the desired complex and 0:1 mole for excess.
  • the chromic acid may not all be reduced, and the residue may be detrimental for further work.
  • the chromic acid, dissolved in water should be cautiously added to the glycolic acid dissolved in water at 90-100 C. When all added, the solution should be boiled for one hour to complete the reaction. It is very undesirable to reverse the order of addition, because then the reaction mixture sets to a gel before all the glycolic acid is added.
  • the product of the reaction is a deep green solution which evaporates to a non-crystalline green glassy ma terial.
  • This material appears to be a basic chromium glycolate complex containing one gram mole of glycolic acid per gram atom of chromium, together with about 0.1 mole of free glycolic acid.
  • chromium glycolate complex prepared as above, commercial chemicals are used to make up the rest of the bath. After mixing these, the solution is heated to boiling and then cooled to equilibrate the various chromium complexes that may be present in the bath.
  • Brass plated with I acquired a bright chromium plate the current density range from 25 to over 200 amp/sq. ft. In the upper end of this range the plate appeared a little hazy. Plating efiiciency at amp./ sq. ft, as calculated from weight gain, was about 10% (as good as 20% with a hexavalent chromium bath).
  • Brass plated with II developed a bright chromium plate within the current density range from 25 to over 200 amp/sq. ft, with only a trace of haze at the upper end of the range. Plating efficiency at 100 amp/sq. it. was about 7%.
  • the octyl alcohol is added to improve smoothness and prevent pitting.
  • Nickel plated with this solution developed an extremely bright chromium plate from 18 to over 200 amp/sq. ft. There was no trace of haze.
  • Plating solutions of this type commonly yielded 10 to 17% current eificiency at 100- 200 amp/sq. ft.
  • Example IV Sodium perchlorate, NaClO 2.0 Trivalent chromium, Cr+++ 1.0 Glycolic acid, CH OH-COOH 1.2 Boric acid, H BO 1.0 Octyl alcohol 0.01
  • Brass plated with the above electrolyte acquired a very bright chromium plate with a current density of from 36 to over amperes per square foot.
  • Example VI [Gram moles per liter of solution] Sodium sulfate, Na SO 1.0 Boric acid, H BO 0.7 Trivalent chromium, Cr 1.0 Sodium binoxalate, NaHC O 1.0 Ox-a lic acid, H C O 1.0
  • Brass plated with 'this electrolyte acquired a smooth chromium plate over the current density range of 50 to over, 120 amperes per square root; Thecolor was not as amps/sq; at 20 C. to 65 C(with a cathodic current efliciency of to 25% based on trivalent chromium. Based'on hexavalent chromium; these current efiic'iencim are-1'0 to 50%.) Any pitting of chromium plate may be'eliminated'by the addition of a small amount of a higher alcohol having 5 to 12 carbon atoms, for example, n-octyl alcohol.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
  • Laminated Bodies (AREA)
  • Electroplating Methods And Accessories (AREA)
US844876A 1959-10-07 1959-10-07 Plating bath and process Expired - Lifetime US3006823A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
DENDAT1247803D DE1247803C2 (de) 1959-10-07 Verfahren zur herstellung von selbsttragenden metallverbundfalmen durch galvaniscles abscheiden
US844876A US3006823A (en) 1959-10-07 1959-10-07 Plating bath and process
US47139A US3021267A (en) 1959-10-07 1960-08-03 Plating bath and process
FR840489A FR1275069A (fr) 1959-10-07 1960-10-06 Procédés électrolytiques de chromage brillant et produits en résultant
DEP36210A DE1245678B (de) 1959-10-07 1960-10-07 Waessriges galvanisches Chrombad und Verfahren zum galvanischen Abscheiden von Glanzchromueberzuegen
GB34491/60A GB965684A (en) 1959-10-07 1960-10-07 Improvements in or relating to laminated or coated chromium films
GB44440/63A GB965685A (en) 1959-10-07 1960-10-07 Improvements in or relating to electrolytic plating
DEP36209A DE1245677B (de) 1959-10-07 1960-10-07 Waessriges galvanisches Chrombad und Verfahren zum galvanischen Abscheiden von Glanzchromueberzuegen
DEP25807A DE1247803B (de) 1959-10-07 1960-10-07 Selbsttragender Verbundfilm und Verfahren zur galvansichen Herstellung desselben
US388755A US3203876A (en) 1959-10-07 1964-08-11 Process for preparing chromium film products

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US84487759A 1959-10-07 1959-10-07
US84487559A 1959-10-07 1959-10-07
US84490659A 1959-10-07 1959-10-07
US844876A US3006823A (en) 1959-10-07 1959-10-07 Plating bath and process
US3395160A 1960-06-06 1960-06-06
US47139A US3021267A (en) 1959-10-07 1960-08-03 Plating bath and process

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US3006823A true US3006823A (en) 1961-10-31

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US844876A Expired - Lifetime US3006823A (en) 1959-10-07 1959-10-07 Plating bath and process
US47139A Expired - Lifetime US3021267A (en) 1959-10-07 1960-08-03 Plating bath and process
US388755A Expired - Lifetime US3203876A (en) 1959-10-07 1964-08-11 Process for preparing chromium film products

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US47139A Expired - Lifetime US3021267A (en) 1959-10-07 1960-08-03 Plating bath and process
US388755A Expired - Lifetime US3203876A (en) 1959-10-07 1964-08-11 Process for preparing chromium film products

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US (3) US3006823A (de)
DE (4) DE1245677B (de)
FR (1) FR1275069A (de)
GB (2) GB965685A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3706636A (en) * 1971-02-19 1972-12-19 Du Pont Preparing plating bath containing chromic compound
US3725214A (en) * 1971-02-19 1973-04-03 Du Pont Chromium plating medium for a portable plating device
US3869488A (en) * 1971-02-19 1975-03-04 Du Pont Werner chromium complexes and methods for their preparation
US4053374A (en) * 1975-08-27 1977-10-11 Albright & Wilson Limited Chromium electroplating baths
WO2015134690A1 (en) * 2014-03-07 2015-09-11 Macdermid Acumen, Inc. Passivation of micro-discontinuous chromium deposited from a trivalent electrolyte
US20200308723A1 (en) * 2014-01-24 2020-10-01 Coventya S.P.A. Electroplating bath containing trivalent chromium and process for depositing chromium

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL6800734A (de) * 1967-01-18 1968-07-19
BE788117A (fr) * 1971-08-30 1973-02-28 Perstorp Ab Procede de production d'elements pour circuits imprimes
USRE29820E (en) * 1971-08-30 1978-10-31 Perstorp, Ab Method for the production of material for printed circuits
US3816142A (en) * 1972-05-08 1974-06-11 K Lindemann Electroless chromium plating process and composition
US4376161A (en) * 1981-07-27 1983-03-08 Dynamics Research Corporation Encoder disc and method of manufacture
EP2138607A1 (de) * 2008-06-24 2009-12-30 Nederlandse Organisatie voor toegepast- natuurwetenschappelijk onderzoek TNO Verfahren zur Herstellung eines flexiblen Substrats mit einer Folie aus transparentem leitfähigem Oxid

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB292094A (en) * 1928-03-26 1929-08-08 Ternstedt Mfg Co Improvements in chromium plating
US1922853A (en) * 1927-12-01 1933-08-15 United Chromium Inc Process for the electrolytic deposition of chromium
US2748069A (en) * 1948-03-20 1956-05-29 Iexi Jean Jacques Georges Trivalent chromium plating solution

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2105440A (en) * 1938-01-11 Manufacture of metal coated paper
US198209A (en) * 1877-12-18 Improvement in the manufacture of metallic leaf
US1844751A (en) * 1925-08-12 1932-02-09 United Chromium Inc Process of electrodepositing chromium
US1731415A (en) * 1927-02-23 1929-10-15 William F Grupe Production of electrolytically-deposited gold in film or leaf form
FR661182A (fr) * 1928-01-12 1929-07-22 L Orfevrerie D Ercuis Soc Nouv Perfectionnements apportés au chromage des corps conducteurs
DE642665C (de) * 1934-05-05 1937-03-12 Heinrich Hampel Dr Verfahren zur fortlaufenden elektrolytischen Herstellung von Metallbaendern
GB456749A (en) * 1934-05-14 1936-11-13 Peerless Gold Leaf Company Ltd Improvements in or relating to the manufacture of free gold leaf
US2133685A (en) * 1935-03-11 1938-10-18 Frank R Coughlin Method of removing metallic plating from a carrier band
US2203253A (en) * 1936-09-26 1940-06-04 Western Electric Co Electroplating process
US2517441A (en) * 1945-07-09 1950-08-01 Ductile Chrome Process Co Electrodeposition of chromium
NL132271C (de) * 1961-07-25

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1922853A (en) * 1927-12-01 1933-08-15 United Chromium Inc Process for the electrolytic deposition of chromium
GB292094A (en) * 1928-03-26 1929-08-08 Ternstedt Mfg Co Improvements in chromium plating
US2748069A (en) * 1948-03-20 1956-05-29 Iexi Jean Jacques Georges Trivalent chromium plating solution

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3706636A (en) * 1971-02-19 1972-12-19 Du Pont Preparing plating bath containing chromic compound
US3725214A (en) * 1971-02-19 1973-04-03 Du Pont Chromium plating medium for a portable plating device
US3869488A (en) * 1971-02-19 1975-03-04 Du Pont Werner chromium complexes and methods for their preparation
US4053374A (en) * 1975-08-27 1977-10-11 Albright & Wilson Limited Chromium electroplating baths
US20200308723A1 (en) * 2014-01-24 2020-10-01 Coventya S.P.A. Electroplating bath containing trivalent chromium and process for depositing chromium
US11905613B2 (en) * 2014-01-24 2024-02-20 Coventya S.P.A. Electroplating bath containing trivalent chromium and process for depositing chromium
WO2015134690A1 (en) * 2014-03-07 2015-09-11 Macdermid Acumen, Inc. Passivation of micro-discontinuous chromium deposited from a trivalent electrolyte
CN106103809A (zh) * 2014-03-07 2016-11-09 麦克德米德尖端有限公司 由三价电解质沉积的微不连续铬的钝化
CN106103809B (zh) * 2014-03-07 2018-05-11 麦克德米德尖端有限公司 由三价电解质沉积的微不连续铬的钝化
US10415148B2 (en) 2014-03-07 2019-09-17 Macdermid Acumen, Inc. Passivation of micro-discontinuous chromium deposited from a trivalent electrolyte

Also Published As

Publication number Publication date
DE1247803C2 (de) 1973-03-29
DE1245677B (de) 1967-07-27
FR1275069A (fr) 1961-11-03
US3021267A (en) 1962-02-13
DE1247803B (de) 1967-08-17
GB965685A (en) 1964-08-06
DE1245678B (de) 1967-07-27
GB965684A (en) 1964-08-06
US3203876A (en) 1965-08-31

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