US4648947A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chromium electroplating and bath therefor
Assignee: BTG International Ltd
•
Filing: 1985-05-01
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Granted: 1987-03-10
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Expires: 2005-05-01
Abstract
Abstract To a conventional chromium electroplating bath containing 450 g/l chromic acid CrO3 and 4.5 g/l sulphuric acid H2SO4 are added 10 g/l of potassium perchlorate or potassium bromate or potassium iodate or mixtures thereof. Higher current densities may be used in electrodepositing chromium without impairing the quality.
Inventors
- 👤 John A. Naismith
- 👤 Malcolm McCormick
- 👤 David Howe
- 👤 Malcolm A. Pate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:34
CPC Classifications
C; C25; C25D; C25D3/00; C25D3/02; C25D3/04
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
73 words
A bath composition for chromium electroplating comprising CrO 3 in a concentration of from 200 g/l to 600 g/l, sulphate in a weight ratio SO 4 :CrO 3 of from 1:120 to 1:80, perchlorate in a weight ratio ClO 4 :CrO 3 of from 1:500 to 1:50, bromate in a weight ratio BrO 3 :CrO 3 of from 1:50 to 1:20, and metal cations equivalent to at least half the perchlorate plus bromate.
Claim 2
Dependent Claim
73 words
A bath composition for chromium electroplating comprising CrO 3 in a concentration of from 200 g/l to 600 g/l, sulphate in a weight ratio SO 4 :CrO 3 of from 1:120 to 1:80, perchlorate in a weight ratio ClO 4 :CrO 3 of from 1:500 to 1:50, bromate in a weight ratio BrO 3 :CrO 3 of from 1:50 to 1:20, and metal cations equivalent to at least half the perchlorate plus bromate.
Claim 3
Dependent Claim
23 words
A bath composition according to claim 1, wherein the perchlorate has a weight ratio ClO 4 :CrO 3 of from 1:200 to 1:80.
Claim 4
Dependent Claim
20 words
A bath composition according to claim 1, wherein the metal cations are equivalent to substantially all the perchlorate plus bromate.
Claim 5
Dependent Claim
19 words
A bath composition according to claim 1, wherein some or all of the metal cations are alkali metal cations.
Claim 6
Dependent Claim
16 words
A bath composition according to claim 1, which has been electrolysed before use for chromium electroplating.
Claim 7
Dependent Claim
24 words
A method of electroplating chromium onto a substrate, comprising applying a cathodic potential to the substrate in a bath composition according to claim 1.
Claim 8
Dependent Claim
21 words
A method according to claim 6, wherein the current density on the substrate is from 15 to 50 kA/m 2 .
Claim 9
Dependent Claim
15 words
A method according to claim 6, wherein the temperature is from 45° to 65° C.
References Cited (Backward Citations)
US3654101A
Cited
GB1383524A
Cited
GB1419613A
Cited
GB1464531A
Cited
US4234396A
Cited
EP0073568A1
Cited
US4450050A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-03-09 | 1990-09-08 | 1991-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-09 | 1994-09-08 | 1995-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-09 | 1998-09-08 | 1999-03-10 | $7700.00 | Window Closed / Lapsed |