US2118956A - Method of chromium plating - Google Patents
Method of chromium plating Download PDFInfo
- Publication number
- US2118956A US2118956A US57922A US5792236A US2118956A US 2118956 A US2118956 A US 2118956A US 57922 A US57922 A US 57922A US 5792236 A US5792236 A US 5792236A US 2118956 A US2118956 A US 2118956A
- Authority
- US
- United States
- Prior art keywords
- chromium
- article
- plating
- solution
- chromium 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
Links
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title description 31
- 229910052804 chromium Inorganic materials 0.000 title description 31
- 239000011651 chromium Substances 0.000 title description 31
- 238000007747 plating Methods 0.000 title description 16
- 238000000034 method Methods 0.000 title description 14
- 239000000243 solution Substances 0.000 description 16
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- 238000009713 electroplating Methods 0.000 description 4
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 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 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 239000012670 alkaline solution Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 235000011167 hydrochloric acid Nutrition 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Inorganic materials [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 2
- 235000011149 sulphuric acid Nutrition 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910021555 Chromium Chloride Inorganic materials 0.000 description 1
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000000788 chromium alloy Substances 0.000 description 1
- QSWDMMVNRMROPK-UHFFFAOYSA-K chromium(3+) trichloride Chemical compound [Cl-].[Cl-].[Cl-].[Cr+3] QSWDMMVNRMROPK-UHFFFAOYSA-K 0.000 description 1
- 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 description 1
- 238000002845 discoloration Methods 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 150000003388 sodium compounds Chemical class 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 1
- 229910000406 trisodium phosphate Inorganic materials 0.000 description 1
- 235000019801 trisodium phosphate Nutrition 0.000 description 1
- 238000005406 washing Methods 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
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/34—Pretreatment of metallic surfaces to be electroplated
- C25D5/38—Pretreatment of metallic surfaces to be electroplated of refractory metals or nickel
- C25D5/40—Nickel; Chromium
Definitions
- the article to beplated is-made the cathode ofthe cell and a potential preferably of about 6-18 volts is impressed upon the elec trodes while the article is in the alkaline solution.
- chromium plating operations on parts requiring close limits for the thickness of deposit can be controlled very accurately since the part can be removed from the plating solution, the thickness of the deposit determined and an additional deposit applied if necessary.
- the parts may be treated in accordance with the invention the following day and the plating continued.
- a method of chromium plating on a chromium surface which comprises cathodically treating the article in a bath consisting essentially of a solution of an alkaline compound, immersing
Description
mersed in a hot solution of an alkaline compound,"
- sodium hydroxide or the like, contained in an' Patented May 31-, 1938 PATENT OFFICE 2,113,950 METHOD or cr'mormm rmrmc Arthur Wagner, Riverside, IlLpassig'nor to, Western Electric Company, Incorporated, New York, N. Y., a corporation of New York No Drawing. Application January Serial N0. 57,922
4 Claims. (CL 204-1) This invention relates to a method of chromium plating, and more particularly to a method of chromium plating over a previously chromium plated surface or a surface of a chromium alloy.
Due to chemical changes in the surface of a chromium plated'object when exposed to the atmosphere or when the chromium plating process is interrupted, it is impossible, at leastwith certain well known electroplating processes, to consistently plate chromiumover a previously chromium plated surface or over the surface of a high chromium content alloy. v
In order to chromium plate-a previously chromium plated surface, it has been customary in many instances heretofore to completely strip an article of a previously applied chromium plate and replate the entire coating.
An object of the present invention is to provide an effective and efficient method of electroplating on a chromium surface.
In accordance with the preferred embodiment of the invention, a chromium plated surface which is to receive a further electroplated coating of chromium is placed in an electrolytic cell containing a hot solution of sodium carbonate andmade the cathode therein for one or more minutes after which the article is withdrawn and etched in a hydrochloric acid solution until the surface becomes discolored, the extent of discoloration necessary for any particular type of work can be readily determined by trial. The surface is then washed in cold water whereupon a further chromium plated coating may be applied thereto.
The invention is particularly applicable when chromium plating with the well known Sargent solution using an aqueous chromicacid and sulfuric acid solution having a proportion of from one to five grams of sulphate radical to 250 grams of chromic acid per liter of solution. The chromium surface to be chromium plated ls first im such 'as sodium carbonate, trisodium phosphate,
electrolytic cell. The article to beplated is-made the cathode ofthe cell and a potential preferably of about 6-18 volts is impressed upon the elec trodes while the article is in the alkaline solution.
as a result of which hydrogen is liberated at the surface of the article and acts as a reducing agent for anyoxides that are present. There also appears to be a beneficial hydrogen bombardment of the surface which exposes the chromium by removing a passive film therefrom. This process is continued for one or more minutes after which the article is withdrawn from the bath and is etched in a suitable acid solution, such as a solu tion of hydrochloric or sulphuric acid. This treatment results in the formation of a black smut comprising chromium chloride or chromium sulphate on the surface of the article and after removal from theacid solution the object is washed well in cold water and placed in the chromium plating bath. The smut is not removed during washing but acts as a protective layer on the surface until the article is placed in the plating bath where'it is removed by-the plating process before plating begins. The plating process is then car ried out in the usual manner. I
The process lends itself admirably to the repair of defective chromium plated work, such as parts which have not been entirely covered in a previous plating operation or parts which have become defective or worn in service. Also chromium plating operations on parts requiring close limits for the thickness of deposit can be controlled very accurately since the part can be removed from the plating solution, the thickness of the deposit determined and an additional deposit applied if necessary. In some cases it is also found that when work cannot be completed during the r'egular working day, the parts may be treated in accordance with the invention the following day and the plating continued.
The invention also makes it possible to electr of substantially pure chromium, but also a surface of high chromium content such as is presented by an alloy containing chromium. a
What is claimed is: v
'1. A method of chromium platingon a chromium surface which comprises placing the article to be plated in a bath consisting essentially of a solution of an alkaline compound, passing- .a current through the solution with the article as a cathode, immersing the article in an acid solution of the group consistingof hydrochloric and sul-g phuric acids until a black smut is formed on the surface of the article, and electroplating the article in a chromic acidbath.
- 2. A method of chromium plating on a chromium surface which comprises placing the article in a bath consisting essentially *of an alkaline solution of a sodium compound passing a current through the solution with the article as a cathode,
immersing the article in an acid solution of thegroup consisting of hydrochloric and sulphuric acids until a black smut is formed on the surface of the article, and electroplating the article in a chromic acid bath.
3. A method of chromium plating on a chromium surface which comprises cathodically treating the article in a bath consisting essentially of a solution of an alkaline compound, immersing
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US57922A US2118956A (en) | 1936-01-07 | 1936-01-07 | Method of chromium plating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US57922A US2118956A (en) | 1936-01-07 | 1936-01-07 | Method of chromium plating |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2118956A true US2118956A (en) | 1938-05-31 |
Family
ID=22013574
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US57922A Expired - Lifetime US2118956A (en) | 1936-01-07 | 1936-01-07 | Method of chromium plating |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2118956A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2547120A (en) * | 1945-10-23 | 1951-04-03 | Bendix Aviat Corp | Process for plating a carbon or graphite part with chromium |
| US2574305A (en) * | 1948-09-22 | 1951-11-06 | Gen Motors Corp | Activating process for plating |
| US2893931A (en) * | 1955-02-18 | 1959-07-07 | Terry Ind Inc | Method of plating metallic surfaces |
| US3393134A (en) * | 1965-03-23 | 1968-07-16 | Benno A. Schwartz Jr. | Method of chromium plating |
| US3421986A (en) * | 1964-10-28 | 1969-01-14 | Teves Kg Alfred | Method of electroplating a bright adherent chromium coating onto cast-iron |
-
1936
- 1936-01-07 US US57922A patent/US2118956A/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2547120A (en) * | 1945-10-23 | 1951-04-03 | Bendix Aviat Corp | Process for plating a carbon or graphite part with chromium |
| US2574305A (en) * | 1948-09-22 | 1951-11-06 | Gen Motors Corp | Activating process for plating |
| US2893931A (en) * | 1955-02-18 | 1959-07-07 | Terry Ind Inc | Method of plating metallic surfaces |
| US3421986A (en) * | 1964-10-28 | 1969-01-14 | Teves Kg Alfred | Method of electroplating a bright adherent chromium coating onto cast-iron |
| US3393134A (en) * | 1965-03-23 | 1968-07-16 | Benno A. Schwartz Jr. | Method of chromium plating |
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