US2279830A - Metal plating bath and method of plating - Google Patents
Metal plating bath and method of plating Download PDFInfo
- Publication number
- US2279830A US2279830A US194967A US19496738A US2279830A US 2279830 A US2279830 A US 2279830A US 194967 A US194967 A US 194967A US 19496738 A US19496738 A US 19496738A US 2279830 A US2279830 A US 2279830A
- Authority
- US
- United States
- Prior art keywords
- acid
- plating
- bath
- monochloracetic
- chromic
- 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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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
- C25D3/10—Electroplating: Baths therefor from solutions of chromium characterised by the organic bath constituents used
Definitions
- This invention relates to a metal plating bath and particularly to a method of plating chroonly with narrow ranges of S04 ion concentration and are very low in efilciency.
- a halogen derivative of acetic acid preferably monochloracetic acid, is employed in combination with chromic acid.
- the relative concentrations of chromic acid and monochloracetic acid may be widely varied. Preferably, 5% of monochloracetic acid is used based on the chromic acid because at this ratio makeup chromic acid may be added from time to time in the same relative proportion to monochloracetic acid. However, much higher concentrations may be employed as, for example, 9 oz. of monochloracetic acid to 36 oz. of chromic acid, or as little as 1% may be employed. At the higher concentrations the plating is heavier and the solution tends to heat more rapidly. At the lower concentrations the plating is not so heavy.
- a preferred plating bath comprises. to each gallon of water 36 oz. of chromic acid and 2 oz.
- the solution may be run hot or cold, but is preferably run from 90 to 130 F.
- the current density may be widely varied.
- make-up is added periodically in the origi- 4 nal ratio of 38 to 2 and the process may be operated for months without any analysis, by-making it up in this manner.
- dichloracetic acid and trichloracetic acid while operating satisfactorily, are more expensive and are more corrosive to the hands. These are likewise used around 5%.
- Metallic chromium produced in the layers by this process has a considerablydifierent appearance than the ordinary electrolytic chromium. It has a more metallic look, is heavy, less brittle, and is not-full of cracks.
- the solution' may likewise be used to plate lead, employing a lead nitrate bath.
- a lead nitrate bath For example, in one gallon of water saturated with leadnitrate 10% of glycerin and 5% of monochloracetic acid are employed based on the lead. a low current density is employed and the bath is preferably cold.
- monochloracetic acid likewise increases the efiiciency of a copper plating bath able strength and the color oi which resembles that of copper produced by cooling from fusion.
- a chromium plating bath comprising chro- -mic acid and a minor proportion of a chlorinated 4.
- a plating bath comprising water, chromic. acid and monochloracetic acid, the monochloracetic'belng 1 to 25% of the chromicgacid by weight.
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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)
- Electroplating Methods And Accessories (AREA)
Description
Patented Apr. M, 39421 aerated METAL PLATING BATH AND METHOD OF PLATING John J. Murray, Arlington, Mass.
. No Drawing. Application March 9, 1938,
Serial No. 194,967
8 Claims. "(01. 204-51) This invention relates to a metal plating bath and particularly to a method of plating chroonly with narrow ranges of S04 ion concentration and are very low in efilciency.
In accordance with the present invention a plating solution of relatively high plating elflciency, of considerable stability and one not requiring regulation, is produced.
In accordance with this invention,a halogen derivative of acetic acid, preferably monochloracetic acid, is employed in combination with chromic acid.
The relative concentrations of chromic acid and monochloracetic acid may be widely varied. Preferably, 5% of monochloracetic acid is used based on the chromic acid because at this ratio makeup chromic acid may be added from time to time in the same relative proportion to monochloracetic acid. However, much higher concentrations may be employed as, for example, 9 oz. of monochloracetic acid to 36 oz. of chromic acid, or as little as 1% may be employed. At the higher concentrations the plating is heavier and the solution tends to heat more rapidly. At the lower concentrations the plating is not so heavy.
A preferred plating bath comprises. to each gallon of water 36 oz. of chromic acid and 2 oz.
of monochloracetic acid. With such a bath, it is preferable to use a lead electrode.
7 The solution may be run hot or cold, but is preferably run from 90 to 130 F. The current density may be widely varied.
and produces a copper film which has considerof chromic acid to 2- oz. of monochloracetic acid,
the deposit on a square foot. is approximately .0003" in five minutes. This uses up approximately V oz. oi chromic acid and a correspondin: amount or monochloracetic acid. Accordingly, make-up is added periodically in the origi- 4 nal ratio of 38 to 2 and the process may be operated for months without any analysis, by-making it up in this manner.
For the brighter chromium finishes, it is preferred to keep the current density lower,.ior example, plating only .00015 in four minutes.
In the bathherein described. chromium plating Y the bath without any previous cleaning whatsoever, if desired.
The dichloracetic acid and trichloracetic acid, while operating satisfactorily, are more expensive and are more corrosive to the hands. These are likewise used around 5%.
Metallic chromium produced in the layers by this process has a considerablydifierent appearance than the ordinary electrolytic chromium. It has a more metallic look, is heavy, less brittle, and is not-full of cracks.
The solution'may likewise be used to plate lead, employing a lead nitrate bath. For example, in one gallon of water saturated with leadnitrate 10% of glycerin and 5% of monochloracetic acid are employed based on the lead. a low current density is employed and the bath is preferably cold. The use of monochloracetic acid likewise increases the efiiciency of a copper plating bath able strength and the color oi which resembles that of copper produced by cooling from fusion.
The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible in view of the prior art.
I claim: 1. A chromium plating bath comprising chro- -mic acid and a minor proportion of a chlorinated 4. A plating bath comprising water, chromic. acid and monochloracetic acid, the monochloracetic'belng 1 to 25% of the chromicgacid by weight.
5. A process for electroplating chromium,-
which comprises passing an eiectriccurrent from an anode to a cathode through an aqueous solution of chromic acid and monochloracetic acid.
6. The method as set forth in claim 5, in which the bath comprises approximately 1 gallon of water, 36 ounces of chromic acid and 2 to 9 ouncesof monochloracetic acid.
7. The method as set forth in claim 5, in which the bath comprises water, chromic acid and monochloracetic acid in the proportion oil to 25% or chromic acid by weight. V p 8. The method of plating chromium which.v
comprises passing an electric current through an electrolyte solution comprisingchromic acid and a minor proportion of a chlorinated acetic acid.
' JQHN J'.'MURRAY.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US194967A US2279830A (en) | 1938-03-09 | 1938-03-09 | Metal plating bath and method of plating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US194967A US2279830A (en) | 1938-03-09 | 1938-03-09 | Metal plating bath and method of plating |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2279830A true US2279830A (en) | 1942-04-14 |
Family
ID=22719552
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US194967A Expired - Lifetime US2279830A (en) | 1938-03-09 | 1938-03-09 | Metal plating bath and method of plating |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2279830A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3248310A (en) * | 1962-05-16 | 1966-04-26 | Gen Dev Corp | Bright plating of chromium |
| US3414492A (en) * | 1965-12-14 | 1968-12-03 | Corillium Corp | Chromium plating process |
-
1938
- 1938-03-09 US US194967A patent/US2279830A/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3248310A (en) * | 1962-05-16 | 1966-04-26 | Gen Dev Corp | Bright plating of chromium |
| US3414492A (en) * | 1965-12-14 | 1968-12-03 | Corillium Corp | Chromium plating process |
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