Patent US4384900A successfully refreshed from Google Patents.
US4384900A
Expired / Lapsed
US
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Method of treating metal surfaces prior to phosphatization
Assignee: Gerhard Collardin GmbH
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Filing: 1980-12-22
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Granted: 1983-05-24
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Expires: 2000-12-22
Abstract
Abstract This invention is directed to a method for treating metal surfaces. More particularly, this invention is directed to an improved method for cleaning, scouring, and activating metal surfaces prior to phosphatization, which comprises contacting said metal surfaces with an aqueous solution comprising primary and/or secondary alkali metal or ammonium salts of orthophosphates and conventional metal cleaning components, the solution having a pH value of from about 6.3 to 8.2, said pH being lower than the pH value of solutions of the corresponding secondary orthophosphates alone having the same concentration; and containing optionally condensed phosphates in an amount corresponding to the amount necessary to soften the water hardness of the water used.
Inventors
- 👤 Hans Gotta
- 👤 Karl-Heinz Gottwald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:57
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/78; C23C22/80
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
151 words
In a method for phosphatizing metal surfaces wherein dirty metal surfaces are cleaned and scoured with a cleanser and then acid solution containing phosphates is applied to the cleaned and scoured metal surfaces to form phosphate coatings, the improvement which comprises cleaning, scouring, and activating the metal surfaces in one step with an aqueous solution comprising (a) primary and/or secondary alkali metal or ammonium salts of orthophosphates; (b) from about 1 to 60 percent by weight, based upon the total weight of the solution, of alkali metal borates; (c) conventional metal cleansing components; and (d) optionally condensed phosphates in an amount corresponding to the amount necessary to soften the water hardness of the water used, the solution having a pH value in the range of from about 6.3 to 8.2, said pH value being lower than the pH value of solutions of the corresponding secondary orthophosphates alone having the same concentration.
Claim 2
Dependent Claim
151 words
In a method for phosphatizing metal surfaces wherein dirty metal surfaces are cleaned and scoured with a cleanser and then acid solution containing phosphates is applied to the cleaned and scoured metal surfaces to form phosphate coatings, the improvement which comprises cleaning, scouring, and activating the metal surfaces in one step with an aqueous solution comprising (a) primary and/or secondary alkali metal or ammonium salts of orthophosphates; (b) from about 1 to 60 percent by weight, based upon the total weight of the solution, of alkali metal borates; (c) conventional metal cleansing components; and (d) optionally condensed phosphates in an amount corresponding to the amount necessary to soften the water hardness of the water used, the solution having a pH value in the range of from about 6.3 to 8.2, said pH value being lower than the pH value of solutions of the corresponding secondary orthophosphates alone having the same concentration.
Claim 3
Dependent Claim
18 words
The method of claim 1, wherein the solution has a pH value of from about 6.5 to 8.0.
Claim 4
Dependent Claim
19 words
The method of claim 1, wherein the pH value of the solution is adjusted by addition of phosphoric acid.
Claim 5
Dependent Claim
14 words
The method of claim 1, wherein the metal surfaces are iron or steel surfaces.
Claim 6
Dependent Claim
22 words
The method of claim 1, wherein the metal surfaces are the surfaces of iron or steel in combination with aluminum and/or zinc.
Claim 7
Dependent Claim
14 words
The method of claim 1, wherein the metal surfaces comprise zinc-coated iron or steel.
Claim 8
Dependent Claim
22 words
The method of claim 1, wherein the solution contains alkali metal bicarbonates at a pH value of from about 7 to 8.
Claim 9
Dependent Claim
32 words
The method of claim 7, wherein the alkali metal bicarbonates are present in an amount of from about 1 to 60 percent by weight, based upon the total weight of the solution.
Claim 10
Dependent Claim
13 words
The method of claim 1, wherein the solution contains other calcium-ion sequestering compounds.
Claim 11
Dependent Claim
33 words
The method of claim 9, wherein the other calcium-ion sequestering compounds are present in an amount of from about 1 to 60 percent by weight, based upon the total weight of the solution.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-05-23 | 1986-11-22 | 1987-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-23 | 1990-11-22 | 1991-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-23 | 1994-11-22 | 1995-05-24 | $7700.00 | Window Closed / Lapsed |