US3615892A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composition and method for black coating on metals
Assignee: OAKITE PRODUCTS Inc A DE CORP
•
Filing: 1968-10-30
•
Granted: 1971-10-26
•
Expires: 1988-10-30
Abstract
Abstract This invention relates to the production of a black finish on the surfaces of metals that are electropositive to bismuth, for example, ferrous metals, manganese, and the white metals as aluminum, magnesium, cadmium and zinc. The invention more specifically is that of a method of producing a black finish on the surface of such metal electropositive to bismuth by immersing the metal surface in an acidic solution of a trivalent bismuth salt.
Inventors
- 👤 Edward Heinzelman Jr
- 👤 Tunis S Williamson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:27
CPC Classifications
C; C23; C23C; C23C18/00; C23C18/16; C23C18/31; C23C22/00; C23C22/78; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/1266
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
30 words
An article as claimed in claim 1, wherein said basis metal surface is a metal member of the class consisting of a ferrous metal, manganese, aluminum, magnesium, cadmium, and zinc.
Claim 2
Dependent Claim
70 words
An article as claimed in claim 2, wherein said basis metal surface is one amenable to taking on a phosphate conversion coating when subjected to the action of an acid aqueous phosphate-ion-containing conversion coating solution, and said protective coating is a said phosphate conversion coating produced on and thus integral with said metal surface after said surface initially was covered alone with said relatively uniform finish of black bismuth particles.
Claim 3
Dependent Claim
41 words
An article as claimed in claim 3, wherein said article is a ferrous metal article and said so covered surface is of ferrous metal, and said phosphate conversion coating is integral with said ferrous metal surface by having been produced thereon.
Claim 4
Dependent Claim
110 words
An aqueous coating bath effective to deposit a dense black bismuth coat on an article of a metal electropositive to bismuth, upon immersing said metal article in clean state in said bath for a time sufficient for said bismuth coat to be deposited on it from said bath which comprises an ionizable trivalent bismuth salt dissolved, to an extent sufficient to provide at least about 0.1 percent content of bismuth cation by weight, in water containing dissolved therein inorganic mineral acid in an amount of at least about 12 percent calculated as H2SO4 equivalent and sufficient to dissolve the quantity of said bismuth salt provided in that aqueous acid medium.
Claim 5
Dependent Claim
20 words
A coating bath as claimed in claim 5, wherein said mineral acid consists essentially of sulfuric acid and hydrochloric acid.
Claim 6
Dependent Claim
40 words
A coating bath as claimed in claim 6, wherein the sulfuric acid is the major part of said mineral acids which jointly provide by weight in said bath the equivalent of at least about 12 percent acid calculated as H2SO4.
Claim 7
Dependent Claim
85 words
A coating bath as claimed in claim 7, wherein said bismuth salt is one of the class consisting of its sulfate, the trinitrate, and the trichloride, and is present to the extent to provide a maximum of about 2.0 percent of bismuth cation by weight; the hydrochloric acid is present to the extent of from about 0.5 to about 5.0 percent by weight calculated as 20* B. acid; and said mineral acids provide jointly by weight a maximum of about 25 percent calculated as H2SO4.
Claim 8
Dependent Claim
46 words
A coating bath as claimEd in claim 5, wherein an ionizable copper salt soluble in said bath is present in an amount sufficient to provide the cupric cation to the extent of from about 8 to about 12 percent of the bismuth content of the bath.
Claim 9
Dependent Claim
43 words
A coating bath as claimed in claim 9, wherein said copper salt is selected from cupric chloride, cupric nitrate, and cupric sulfate, and is present in an amount to provide said cupric cation to the extent of about 10 percent of said bismuth.
Claim 10
Dependent Claim
45 words
A coating bath as claimed in claim 5, wherein sulfuric acid is at least the major part of said mineral acid, and dissolved in the bath is a chloride-ion-providing substance selected from hydrochloric acid, an alkali metal chloride, ammonium chloride, bismuth chloride, and copper chloride.
Claim 11
Dependent Claim
57 words
A coating bath as claimed in claim 10, which comprises: from about 17.5 to about 24.6 parts of H2SO4, from about 0.4 to about 0.5 parts of HC1, from about 0.06 to about 0.075 parts of Cu Cl2, from about 0.224 to about 0.284 parts of bismuth, and from about 120 to about 190 parts of water.
Claim 12
Dependent Claim
58 words
A method of producing a relatively uniform black bismuth coating over the surface of an article of a metal which is electropositive to bismuth, which method comprises immersing said metal surface in an aqueous acid coating bath as claimed in claim 5 and for a time sufficient for said black bismuth coating to be produced on said surface.
Claim 13
Dependent Claim
43 words
The method as claimed in claim 13, which comprises thereafter immersing said black bismuth coating-bearing surface in a phosphate conversion coating bath for a time sufficient to produce on said black bismuth coating-bearing surface a phosphate conversion coating enmeshing said black bismuth coating.
Claim 14
Dependent Claim
58 words
A method of producing a relatively uniform black bismuth coating over the surface of an article of a metal which is electropositive to bismuth, which method comprises immersing said metal surface in an aqueous acid coating bath as claimed in claim 7 and for a time sufficient for said black bismuth coating to be produced on said surface.
Claim 15
Dependent Claim
58 words
A method of producing a relatively uniform black bismuth coating over the surface of an article of a metal which is electropositive to bismuth, which method comprises immersing said metal surface in an aqueous acid coating bath as claimed in claim 8 and for a time sufficient for said black bismuth coating to be produced on said surface.
Claim 16
Dependent Claim
58 words
A method of producing a relatively uniform black bismuth coating over the surface of an article of a metal which is electropositive to bismuth, which method comprises immersing said metal surface in an aqueous acid coating bath as claimed in claim 9 and for a time sufficient for said black bismuth coating to be produced on said surface.
Claim 17
Dependent Claim
58 words
A method of producing a relatively uniform black bismuth coating over the surface of an article of a metal which is electropositive to bismuth, which method comprises immersing said metal surface in an aqueous acid coating bath as claimed in claim 10 and for a time sufficient for said black bismuth coating to be produced on said surface.
Claim 18
Dependent Claim
58 words
A method of producing a relatively uniform black bismuth coating over the surface of an article of a metal which is electropositive to bismuth, which method comprises immersing said metal surface in an aqueous acid coating bath as claimed in claim 11 and for a time sufficient for said black bismuth coating to be produced on said surface.
Claim 19
Dependent Claim
58 words
A method of producing a relatively uniform black bismuth coating over the surface of an article of a metal which is electropositive to bismuth, which method comprises immersing said metal surface in an aqueous acid coating bath as claimed in claim 12 and for a time sufficient for said black bismuth coating to be produced on said surface.
Claim 20
Dependent Claim
44 words
The method as claimed in claim 20, which method comprises thereafter immersing said black bismuth coating-bearing surfacE in a phosphate conversion coating bath for a time sufficient to produce on said black bismuth coating-bearing surface a phosphate conversion coating enmeshing said black bismuth coating.
Claim 21
Dependent Claim
121 words
An aqueous concentrate which upon suitable dilution with water provides an aqueous acid coating bath effective to deposit a dense black bismuth deposit on a metal electropositive to bismuth by immersing therein said metal for a sufficient time therefor, which concentrate comprises an ionizable trivalent bismuth salt dissolved to an extent sufficient to provide from about 0.6 to about 2 percent content of bismuth cation by weight, in water containing dissolved therein mineral acid in the range of from about 25 to about 53 percent by weight calculated as H2SO4 and with sulfuric acid being the major part of said acid content; and hydrochloric acid from none to about 10 percent, calculated as 20* B. acid, by weight of said concentrate.
Claim 22
Dependent Claim
18 words
The aqueous concentrate as claimed in claim 22, wherein the mineral acid consists substantially entirely of sulfuric acid.
Claim 23
Dependent Claim
58 words
The aqueous concentrate as claimed in claim 22, which includes also a chloride-ion-providing substance selected from the class consisting of hydrochloric acid, an alkali metal chloride, ammonium chloride, bismuth trichloride, and cupric chloride, to the extent to provide at most about 3.2 percent chloride ion by weight, and the bismuth cation content is at most said 2 percent.
Claim 24
Dependent Claim
37 words
The concentrate as claimed in claim 22, wherein said concentrate contains a water-soluble cupric salt in an amount to provide the cupric cation to the extent of from about 8 to about 12 percent of the bismuth.
Claim 25
Dependent Claim
16 words
The concentrate as claimed in claim 25, wherein hydrochloric acid is present within its said range.
Claim 26
Dependent Claim
33 words
A coating bath as claimed in claim 5, wherein said ionizable bismuth salt is present therein to the extent to provide therein up to a maximum of about 2.0 percent of bismuth cation.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |