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US4398968A
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Method of boronizing transition metal surfaces
Assignee: ENERGY United States, Department of
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Filing: 1981-08-28
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Granted: 1983-08-16
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Expires: 2001-08-28
Abstract
Abstract A method is presented for preparing a boride layer on a transition metal substrate for use in corrosive environments or as a harden surface in machine applications. This method is particularly useful in treating current collectors for use within a high temperature and corrosive electrochemical cell environment. A melt of a alkali metal boride tetrafluoride salt including such as KF to lower its melting point is prepared including a dissolved boron containing material, for instance NiB, MnB 2 , or CrB 2 . A transition metal to be coated is immersed in the melt at a temperature of no more than 700° C. and a surface boride layer of that transition metal is formed within a period of about 24 hours on the substrate surface.
Inventors
- 👤 Koichiro Koyama
- 👤 Hiroshi Shimotake
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:06
CPC Classifications
C; C23; C23C; C23C12/00; C23C12/02; C23C8/00; C23C8/40; C23C8/42; H; H01; H01M; H01M4/00; H01M4/02; H01M4/64; H01M4/66; Y; Y02; Y02E; Y02E60/00; Y02E60/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
73 words
A method of preparing a corrosion resistant coating on a transition metal substrate comprising: preparing a melt including an alkali metal boron tetraflouride salt; dispersing and at least partially dissolving a particulate transition metal boride in said melt; and immersing said transition metal in said melt, while said melt is at a temperature of no more than 700° C., to form a surface layer on said transition metal containing a transition metal boride.
Claim 2
Independent Claim
73 words
A method of preparing a corrosion resistant coating on a transition metal substrate comprising: preparing a melt including an alkali metal boron tetraflouride salt; dispersing and at least partially dissolving a particulate transition metal boride in said melt; and immersing said transition metal in said melt, while said melt is at a temperature of no more than 700° C., to form a surface layer on said transition metal containing a transition metal boride.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein said transition metal is nickel.
Claim 4
Independent Claim
80 words
A method of boronizing a transition metal comprising: preparing a melt including an alkali metal boron tetrafluoride salt; dissolving a boron containing material selected from the group of metal boride compounds consisting of CrB 2 , MnB 2 , NiB, FeB, ZrB 12 and GdB 6 in said melt; and immersing said transition metal in said melt at a temperature of no more than 700° C. to form a surface layer on said transition metal containing a transition metal boride.
Claim 5
Independent Claim
80 words
A method of boronizing a transition metal comprising: preparing a melt including an alkali metal boron tetrafluoride salt; dissolving a boron containing material selected from the group of metal boride compounds consisting of CrB 2 , MnB 2 , NiB, FeB, ZrB 12 and GdB 6 in said melt; and immersing said transition metal in said melt at a temperature of no more than 700° C. to form a surface layer on said transition metal containing a transition metal boride.
Claim 6
Dependent Claim
24 words
The method of claim 3 wherein said boron containing material is selected from the group consisting of CrB 2 , MnB 2 and NiB.
Claim 7
Dependent Claim
25 words
The method of claim 1 wherein said melt includes in mixture a minor proportion of KF sufficient to lower the melting point of the mixture.
Claim 8
Dependent Claim
21 words
The method of claim 5 wherein the transition metal is immersed in said melt at a temperature of about 550° C.
Claim 9
Dependent Claim
37 words
The method of claim 1 wherein said alkali metal boron tetraflouride salt is selected from the group of such salts consisting of KBF 4 , KBF 4 -KF, NaBF 4 NaBF 4 -KBF 4 and mixtures thereof.
Claim 10
Dependent Claim
23 words
The method of claim 7 wherein said alkali metal boron tetraflouride salt is KBF 4 in mixture with a minor proportion of KF.
Claim 11
Independent Claim
111 words
A method of preparing a current collector structure for a high temperature electrochemical cell employing a molten metal halide salt as electrolyte comprising: providing a current collector structure comprising a transition metal substrate; providing a melt of alkali metal boron tetraflouride salt including a dissolved boron containing material, said boron containing material selected from the group of metal boride compounds consisting of CrB 2 , MnB 2 , NiB, FeB, ZrB 12 and GdB 6 ; and immersing said substrate in said melt, while said melt is at a temperature of less than 700° C., to form a corrosion resistant layer of transition metal boride on the surface of the substrate.
Claim 12
Independent Claim
111 words
A method of preparing a current collector structure for a high temperature electrochemical cell employing a molten metal halide salt as electrolyte comprising: providing a current collector structure comprising a transition metal substrate; providing a melt of alkali metal boron tetraflouride salt including a dissolved boron containing material, said boron containing material selected from the group of metal boride compounds consisting of CrB 2 , MnB 2 , NiB, FeB, ZrB 12 and GdB 6 ; and immersing said substrate in said melt, while said melt is at a temperature of less than 700° C., to form a corrosion resistant layer of transition metal boride on the surface of the substrate.
Claim 13
Dependent Claim
56 words
The method of claim 9 wherein said transition metal is selected from the group of transition metals consisting of Ni and Fe, said alkali metal tetraflouride salt comprising a mixture of a major proportion of KBF 4 and a minor proportion of KF, and said boron containing material comprising NiB, CrB 2 or MnB 2 .
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |