GB872385A - Improvements relating to the replenishment of chromate baths used for treating zinc and cadmium - Google Patents
Improvements relating to the replenishment of chromate baths used for treating zinc and cadmiumInfo
- Publication number
- GB872385A GB872385A GB14441/60A GB1444160A GB872385A GB 872385 A GB872385 A GB 872385A GB 14441/60 A GB14441/60 A GB 14441/60A GB 1444160 A GB1444160 A GB 1444160A GB 872385 A GB872385 A GB 872385A
- Authority
- GB
- United Kingdom
- Prior art keywords
- acid
- solution
- zinc
- replenished
- cadmium
- 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
Links
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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/24—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing hexavalent chromium compounds
Landscapes
- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Treatment Of Metals (AREA)
Abstract
In a process for treating surfaces of zinc or cadmium or alloys consisting predominantly of one or both of these metals by means of a solution containing hexavalent chromium and one or more activating or other additions, periodical replenishment of the solution is effected with a solution containing hexavalent chromium in an amount such as to restore the original concentration and, for each grammol of CrO3 added as acid, from 1.5 to 7.0 gram equivalents of an acid with a pk less than 5.0. If a dichromate is used to replenish the hexavalent chromium an additional gram equivalent of the acid is required, while if a chromate is used, two additional gram equivalents of the acid are required. The replenishment solution may also contain the activating or other additions in proportion to the amounts lost by drag-out. Thus the added acid may serve simultaneously to introduce activating anions lost by drag-out. In the Examples, (1) a solution for brightening galvanized surfaces contains chromic, nitric and sulphuric acid and is replenished with these acids, (2) a solution for yellow-chromating p pure zinc, die-cast zinc and cadmium-plated parts contains chromic acid and sodium chloride and is replenished with chromium acid, sodium chloride and nitric acid, (3) a solution for yellow-chromating pure zinc and injection-moulded zinc articles contains chromic acid, sodium chloride, sodium sulphate and nitric acid and is replenished with a solution containing these compounds, and (4) a solution of green-chromating galvanized sheets and pure zinc sheets contains chromic acid, nitric acid and sodium formate and is replenished with chromic acid, sodium nitrate and formic acid. Other additions which may be present in solutions of this type are magnesium ions and radicals of fluoride and boric acid.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE872385X | 1959-04-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB872385A true GB872385A (en) | 1961-07-12 |
Family
ID=6816001
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB14441/60A Expired GB872385A (en) | 1959-04-23 | 1960-04-25 | Improvements relating to the replenishment of chromate baths used for treating zinc and cadmium |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB872385A (en) |
-
1960
- 1960-04-25 GB GB14441/60A patent/GB872385A/en not_active Expired
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