US2801214A - Chromium plating bath - Google Patents
Chromium plating bath Download PDFInfo
- Publication number
- US2801214A US2801214A US573332A US57333256A US2801214A US 2801214 A US2801214 A US 2801214A US 573332 A US573332 A US 573332A US 57333256 A US57333256 A US 57333256A US 2801214 A US2801214 A US 2801214A
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- United States
- Prior art keywords
- grams
- chromium
- bath
- urea
- plating
- 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
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- 238000007747 plating Methods 0.000 title claims description 23
- 229910052804 chromium Inorganic materials 0.000 title claims description 18
- 239000011651 chromium Substances 0.000 title claims description 18
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title claims description 17
- ZHNUHDYFZUAESO-UHFFFAOYSA-N Formamide Chemical compound NC=O ZHNUHDYFZUAESO-UHFFFAOYSA-N 0.000 claims description 26
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 15
- 239000004202 carbamide Substances 0.000 claims description 15
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 claims description 8
- 229940055042 chromic sulfate Drugs 0.000 claims description 7
- 229910000356 chromium(III) sulfate Inorganic materials 0.000 claims description 7
- 235000015217 chromium(III) sulphate Nutrition 0.000 claims description 7
- 239000011696 chromium(III) sulphate Substances 0.000 claims description 7
- 239000007864 aqueous solution Substances 0.000 claims description 5
- 229910052938 sodium sulfate Inorganic materials 0.000 claims description 5
- 235000011152 sodium sulphate Nutrition 0.000 claims description 5
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 3
- FQLQNUZHYYPPBT-UHFFFAOYSA-N potassium;azane Chemical compound N.[K+] FQLQNUZHYYPPBT-UHFFFAOYSA-N 0.000 claims 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 10
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 8
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- 238000007792 addition Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 6
- 235000011130 ammonium sulphate Nutrition 0.000 description 6
- 150000003839 salts Chemical class 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 229910052939 potassium sulfate Inorganic materials 0.000 description 4
- 235000011151 potassium sulphates Nutrition 0.000 description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 3
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000011591 potassium Substances 0.000 description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 2
- 229940044197 ammonium sulfate Drugs 0.000 description 2
- 150000001844 chromium Chemical class 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000007062 hydrolysis Effects 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 231100000614 poison Toxicity 0.000 description 2
- 230000007096 poisonous effect Effects 0.000 description 2
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 1
- 229910001369 Brass Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- OIDPCXKPHYRNKH-UHFFFAOYSA-J chrome alum Chemical compound [K]OS(=O)(=O)O[Cr]1OS(=O)(=O)O1 OIDPCXKPHYRNKH-UHFFFAOYSA-J 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000002659 electrodeposit Substances 0.000 description 1
- 238000004070 electrodeposition Methods 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 235000019253 formic acid Nutrition 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
Classifications
-
- 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
- C25D3/06—Electroplating: Baths therefor from solutions of chromium from solutions of trivalent chromium
Definitions
- the invention relates in general to the electrodeposition of metallic chromium from an aqueous electrolytic bath which includes urea and more particularly to the addition of formamide to the urea type bath.
- Another object of the invention is to provide a chromium plating bath wherein the use of chromic acid is obviated thereby also dispensing with the use of a highly corrosive material and also circumventing the poisonous gases resulting during the plating operation.
- the resulting savings in cost of original installations such as blowers, fans, etc. and containers for the chromic acid will be apparent.
- Electrolytic bath used in the present invention contains in a liter: 26.6 to 133 grams of tri-valent chro- 'ice mium; to 500 grams of urea; 50 to 300 grams of a 100 ml. of formamide.
- 'Ihe bath is preferably prepared by introducing commercial chromic sulfate in water along with ammonium, potassium or sodium sulfate.
- Other materials which may also be used as conducting salts in the herein disclosed invention are salts of the following elements; namely, aluminum, lithium, magnesium, rubidiirm and cesium.
- the tri-valent chromium for the bath may be obtained by dissolving chromium sulfate in water, by starting with hexavalent chromium and reducing it down to the tri-valent form with sulfur dioxide or hydrogen peroxide, or by dissolving a chrome-alum solution in water.
- the materials are preferably heated to facilitate the dissolving of the materials in the water.
- the ma.- terials are then cooled down below F., and the urea and formamide are added to the mixture.
- the pH of the bath is preferably in the range of from 1.5 to 4.0 although the operator may wish to vary the pH outside of this range which has been given to vary the type of deposit for different plating needs.
- the diaphragm may be of concrete or clay or other suitable materials well known in plating .art and was arranged centrally in the cell to form a central chamber and a surrounding chamber therearound.
- the catholyte or electrolytic bath hereinabove described was introduced into the central chamber and a cathode was hung therein which consisted of a conductor to be electrodeposited.
- An anolyte of dilute sulfuric acid was introduced into the surrounding chamber and platinum anodes were hung therein.
- a diaphragm to separate anolyte from catholyte is highly desirable. Even though hexavalent chromium is formed quite slowly without a diaphragm, covering power and efliciency decline immediately when an anode is introduced directly into the plating bath. Furthermore the added complication of decomposing hexavalent chromium periodically would be some detriment to any industrial use.
- the temperature of. the bath should be limited to a maximum temperature of 120 F. at all times. High temperatures will cause hydrolysis of formamide and urea causing black streaks to appear on the plate.
- the pH of the solution will rise very slowly with time and use but additions of sulfuric acid to lower the pH are not needed more often than in conventional nickel or acid copper plating baths.
- the exact pH range is, as mentioned hereinabove, quite flexible since the operator may wish to vary the type of deposit for ditierent plating needs; A low-pH give zero efficiency at low current density areas while a' high'pH reduces overall efliciency and often shows a blue color-'at low current density areas.
- Urea helps prevent the hydrolysis of. the. formamide andalso overcomes the effects'of'smallamounts of formic acid which'may' occur; It'also prevents precipitation of salts from highly concentrated solutions at room temperaa tures. No-exact ratio'of' urea content to chromium content is to be implied; An excess may cause high viscosity and-resistivity of the bath but no other ill effects.
- ferrous sulfate (about g./li'ter) improves brightness and'ductility. If'a buildup of iron is expected from plating directly'on' iron or steel, the initial addition of iron'may beomitted.
- A' practical example'illustratin'g the present invention is as follows: An aqueous solution is used which contains per'literthe following constituents: 305 grams of chromic sulfate; 200 grams of ammonium sulfate; 400 grarns'of ureaand' 10 'ml'. of formamide; The chromic sulfate'and the ammoniumsulfate were dissolved in water by 'the'addition ofheat. The mixture was then allowed to cool down below at'least' 120 F. and the necessary amount of urea to'conform to the above referred to concentrations per liter was then added to the solution.
- Formamide was then added to provide a concentration of 10 ml; thereof tol liter ofsolution.
- the solution was then addedto the central chamber of the above described cell as catholyte; Dilute sulfuric acid was added to the outer'chamber as catholyte and aplatinum anode was suspended therein.
- A'brass strip was suspended in the catholyte' as a cathode. After 50 ampere-hours/liter had' been passed through the solution the chromium deposits produced. were still good. Appropriate additions of chromic sulfate and urea'plus a small amount of sulfuric acid tolower the pH were made. After three more 50 ampere-hours/liter periods along with the same additions, the solution still continued to produce excellent deposits.
- a chromium plating. bath comprising an aqueous solution containing per liter 100 to 500 grams chromic sulfate, 100 to 500 gramsurea; to 300 grams of a substance selected from the group consisting of ammonium, potassium and sodium sulfate, and l to ml. formamide.
- chromium 100 to- 500 grams'urea, 50 to 300 grams of a substance selected from the group consisting of ammonium, potassium, and sodium sulfate, and 1 to 100' ml. formamide;
- A- chromium plating bath comprising an aqueous solution containingper liter 26.6 to 133 grams tri-valent chromium; 100m 500' grams urea, 50 to 300 grams of a conducting salt, and 1 to 100 ml. formamide.
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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
7 United States Patent CHROMIUM PLATING BATH Melvin R. Zell, Cleveland, Ohio No Drawing. Application March 23, 1956, Serial No. 573,332
3 Claims. (Cl. 204-51) The invention relates in general to the electrodeposition of metallic chromium from an aqueous electrolytic bath which includes urea and more particularly to the addition of formamide to the urea type bath.
The disadvantages encountered in utilizing the so-called chromic acid process industrially for chromium plating are quite well known and many attempts have been made to produce a plating bath without the use of chromic acid. The use of chromic acid is dangerous in that it is highly corrosive in and of itself, during plating operations there is an abundant evolution of poisonous gases, and it has an exceedingly low current efficiency.
One such attempt to circumvent the use of the chromic acid process has been described and disclosed in U. S. Patent No. 2,704,273, issued to Tadashi Yoshida on March 15, 1955. In the plating bath disclosed in this patent, urea has been used as an additive in certain described proportions along with chromic sulfate and ammonium, sodium and potassium sulfate. This patent also disclosed an aging process for the bath and an anode of a particular composition. The electrodeposits produced in practicing the invention taught by the Yoshida patent are extremely brittle and are in such condition of stress that they tend to peel oif in flakes while still in the bath, especially when attempts are made to plate to appreciable thickness.
After much experimentation, it has been found that by the addition of as little as 1 ml. of formamide to a liter of any chromium salt gives a startling improvement in appearance, smoothness, covering and throwing power, and in ductility along with adherence.
It is therefore an object of this invention to provide a chromium plating bath of the urea type which is practical from the platers standpoint and which will provide a chromium plate of exceptional adherence, ductility, and appearance.
Another object of the invention is to provide a chromium plating bath wherein the use of chromic acid is obviated thereby also dispensing with the use of a highly corrosive material and also circumventing the poisonous gases resulting during the plating operation. The resulting savings in cost of original installations such as blowers, fans, etc. and containers for the chromic acid will be apparent.
Public sentiment against the use of the chromic acid process because of the obvious danger to the health of the workmen, has been on the increase for some time and will inevitably result in a drastic legislation to curtail the use of this material. It is for these reasons that an economical chromium plating bath, other than the chromic acid bath, be developed and introduced to the trade. The use of chromium salts would obviate the necessity of plating plants expending large sums of money in installing units to take care of used or contaminated liquids in the plating process.
Electrolytic bath The electrolytic bath used in the present invention contains in a liter: 26.6 to 133 grams of tri-valent chro- 'ice mium; to 500 grams of urea; 50 to 300 grams of a 100 ml. of formamide. 'Ihe bath is preferably prepared by introducing commercial chromic sulfate in water along with ammonium, potassium or sodium sulfate. Other materials which may also be used as conducting salts in the herein disclosed invention are salts of the following elements; namely, aluminum, lithium, magnesium, rubidiirm and cesium. The tri-valent chromium for the bath may be obtained by dissolving chromium sulfate in water, by starting with hexavalent chromium and reducing it down to the tri-valent form with sulfur dioxide or hydrogen peroxide, or by dissolving a chrome-alum solution in water. The materials are preferably heated to facilitate the dissolving of the materials in the water. The ma.- terials are then cooled down below F., and the urea and formamide are added to the mixture. The pH of the bath is preferably in the range of from 1.5 to 4.0 although the operator may wish to vary the pH outside of this range which has been given to vary the type of deposit for different plating needs. Although the components listed above within the limits given, produce good results, better results are obtained if the following limits are observed. Per liter 66.4 to 93.0 grams of tri-valent chromium; 300 to 400 grams of urea; 200 to 300 grams of a conducting salt and 5 to 20 ml. of formamide.
Equipment An acid proof, open cell was used having a diaphragm to separate anolyte from catholyte. The diaphragm may be of concrete or clay or other suitable materials well known in plating .art and was arranged centrally in the cell to form a central chamber and a surrounding chamber therearound. The catholyte or electrolytic bath hereinabove described was introduced into the central chamber and a cathode was hung therein which consisted of a conductor to be electrodeposited. An anolyte of dilute sulfuric acid was introduced into the surrounding chamber and platinum anodes were hung therein.
A diaphragm to separate anolyte from catholyte is highly desirable. Even though hexavalent chromium is formed quite slowly without a diaphragm, covering power and efliciency decline immediately when an anode is introduced directly into the plating bath. Furthermore the added complication of decomposing hexavalent chromium periodically would be some detriment to any industrial use.
It was found that much better cathode efliciency and covering power were obtained when the plating solution was enclosed within the diaphragm material which was in turn surrounded by the anolyte of dilute sulfuric acid. The total electrical resistance of such system was found to be actually less than that of the simple system of cathode and anode inserted directly into the bath. An anode of nearly any conducting material, not readily attacked, may be used in the anolyte. It should be readily understood that the use of the diaphragm is by no means mandatory in practicing the present invention but only used to illustrate a preferred working example of the invention.
Operation In operation the temperature of. the bath should be limited to a maximum temperature of 120 F. at all times. High temperatures will cause hydrolysis of formamide and urea causing black streaks to appear on the plate. The pH of the solution will rise very slowly with time and use but additions of sulfuric acid to lower the pH are not needed more often than in conventional nickel or acid copper plating baths. The exact pH range is, as mentioned hereinabove, quite flexible since the operator may wish to vary the type of deposit for ditierent plating needs; A low-pH give zero efficiency at low current density areas while a' high'pH reduces overall efliciency and often shows a blue color-'at low current density areas.
Urea helps prevent the hydrolysis of. the. formamide andalso overcomes the effects'of'smallamounts of formic acid which'may' occur; It'also prevents precipitation of salts from highly concentrated solutions at room temperaa tures. No-exact ratio'of' urea content to chromium content is to be implied; An excess may cause high viscosity and-resistivity of the bath but no other ill effects.
The. presence of ferrous sulfate. (about g./li'ter) improves brightness and'ductility. If'a buildup of iron is expected from plating directly'on' iron or steel, the initial addition of iron'may beomitted.
' A' practical example'illustratin'g the present invention" is as follows: An aqueous solution is used which contains per'literthe following constituents: 305 grams of chromic sulfate; 200 grams of ammonium sulfate; 400 grarns'of ureaand' 10 'ml'. of formamide; The chromic sulfate'and the ammoniumsulfate were dissolved in water by 'the'addition ofheat. The mixture was then allowed to cool down below at'least' 120 F. and the necessary amount of urea to'conform to the above referred to concentrations per liter was then added to the solution. Formamide was then added to provide a concentration of 10 ml; thereof tol liter ofsolution. The solution was then addedto the central chamber of the above described cell as catholyte; Dilute sulfuric acid was added to the outer'chamber as catholyte and aplatinum anode was suspended therein. A'brass strip was suspended in the catholyte' as a cathode. After 50 ampere-hours/liter had' been passed through the solution the chromium deposits produced. were still good. Appropriate additions of chromic sulfate and urea'plus a small amount of sulfuric acid tolower the pH were made. After three more 50 ampere-hours/liter periods along with the same additions, the solution still continued to produce excellent deposits.
It should be readily understood that the appended claims 'as well as' the-hereinabove given description formthe original disclosure.
Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.
What is claimed is:
1. A chromium plating. bath comprising an aqueous solution containing per liter 100 to 500 grams chromic sulfate, 100 to 500 gramsurea; to 300 grams of a substance selected from the group consisting of ammonium, potassium and sodium sulfate, and l to ml. formamide.
2.-A chromium plating bath comprising an aqueous solution containing perliter 26.6 to" 133 grams tri-valent,
chromium; 100 to- 500 grams'urea, 50 to 300 grams ofa substance selected from the group consisting of ammonium, potassium, and sodium sulfate, and 1 to 100' ml. formamide;
3. A- chromium plating bath comprising an aqueous solution containingper liter 26.6 to 133 grams tri-valent chromium; 100m 500' grams urea, 50 to 300 grams of a conducting salt, and 1 to 100 ml. formamide.
References Cited in thefile of this patent UNITED STATES PATENTS 526,114 Pl-acet et a1 Sept. 18, 1894 1,975,239 Ungelenk et a1. Oct. 2, 1934 2,704,273 Yoshida Mar. 15, 1955 OTHER REFERENCES Raub et al.: Metal Finishing, June 1940, page 315.
Claims (1)
1. A CHROMIUM PLATING BATH COMPRISING AN AQUEOUS SOLUTION CONTAINING PER LITER 100 TO 500 GRAMS CHROMIC SULFATE, 100 TO 500 GRAMS UREA, 50 TO 300 GRAMS OF A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF AMMONIUM POTASSIUM AND SODIUM SULFATE, AND 1 TO 100 ML. FORMAMIDE.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US573332A US2801214A (en) | 1956-03-23 | 1956-03-23 | Chromium plating bath |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US573332A US2801214A (en) | 1956-03-23 | 1956-03-23 | Chromium plating bath |
Publications (1)
Publication Number | Publication Date |
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US2801214A true US2801214A (en) | 1957-07-30 |
Family
ID=24291551
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US573332A Expired - Lifetime US2801214A (en) | 1956-03-23 | 1956-03-23 | Chromium plating bath |
Country Status (1)
Country | Link |
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US (1) | US2801214A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4406756A (en) * | 1981-07-13 | 1983-09-27 | Canadian Corporate Management Company Limited | Hard chromium plating from hexavalent plating bath |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US526114A (en) * | 1894-09-18 | Emile placet and joseph bonnet | ||
US1975239A (en) * | 1929-10-16 | 1934-10-02 | Siemens Ag | Method of chromium plating |
US2704273A (en) * | 1951-09-28 | 1955-03-15 | Yoshida Tadashi | Process for chromium electrodeposition |
-
1956
- 1956-03-23 US US573332A patent/US2801214A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US526114A (en) * | 1894-09-18 | Emile placet and joseph bonnet | ||
US1975239A (en) * | 1929-10-16 | 1934-10-02 | Siemens Ag | Method of chromium plating |
US2704273A (en) * | 1951-09-28 | 1955-03-15 | Yoshida Tadashi | Process for chromium electrodeposition |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4406756A (en) * | 1981-07-13 | 1983-09-27 | Canadian Corporate Management Company Limited | Hard chromium plating from hexavalent plating bath |
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