US4011099A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of damage-free surface on alpha-alumina
Assignee: Monsanto Co
•
Filing: 1975-11-07
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Granted: 1977-03-08
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Expires: 1995-11-07
Abstract
Abstract A chemical polishing process for alpha-alumina utilizing a silica colloid polishing fluid which is both a reactant and a medium for the removal of the reaction product is disclosed.
Inventors
- 👤 Henry W. Gutsche
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:20
CPC Classifications
C; C09; C09K; C09K13/00; C09K13/04; C09G; C09G1/00; C09G1/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
19 words
A process for preparing an undamaged surface on alpha-alumina comprising polishing an alpha-alumina surface with a colloidal silica fluid.
Claim 2
Dependent Claim
19 words
A process for preparing an undamaged surface on alpha-alumina comprising polishing an alpha-alumina surface with a colloidal silica fluid.
Claim 3
Dependent Claim
15 words
A process as claimed in claim 1, wherein said fluid comprises colloidal silica in water.
Claim 4
Dependent Claim
18 words
A process as claimed in claim 2, wherein said fluid has a pH of about 7 to 8.
Claim 5
Dependent Claim
14 words
A process as claimed in claim 2, wherein said fluid further comprises hydrochloric acid.
Claim 6
Dependent Claim
20 words
A process as claimed in claim 2, wherein said colloidal silica has a particle size of 250 - 300 Angstroms.
Claim 7
Dependent Claim
60 words
A process for preparing an undamaged surface on alpha-alumina comprising the steps of: a. shaping the alpha-alumina with a diamond-impregnated saw blade; b. heating to about 1000° C in oxygen until all traces of diamond are removed; c. polishing with a colloidal silica fluid under pressure; d. immersing the alpha-alumina in hydrofluoric acid; followed by e. rinsing in deionized water.
Claim 8
Dependent Claim
60 words
A process for preparing an undamaged surface on alpha-alumina comprising the steps of: a. shaping the alpha-alumina with a diamond-impregnated saw blade; b. heating to about 1000° C in oxygen until all traces of diamond are removed; c. polishing with a colloidal silica fluid under pressure; d. immersing the alpha-alumina in hydrofluoric acid; followed by e. rinsing in deionized water.
Claim 9
Dependent Claim
15 words
A process as claimed in claim 6, wherein said fluid comprises colloidal silica in water.
Claim 10
Dependent Claim
18 words
A process as claimed in claim 6, wherein said fluid has a pH of about 7 to 8.
Claim 11
Dependent Claim
14 words
A process as claimed in claim 6, wherein said fluid further comprises hydrochloric acid.
Claim 12
Dependent Claim
20 words
A process as claimed in claim 6, wherein said colloidal silica has a particle size of 250 - 300 Angstroms.
References Cited (Backward Citations)
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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) | 1980-03-07 | 1980-09-06 | 1981-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-07 | 1984-09-06 | 1985-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-07 | 1988-09-06 | 1989-03-08 | $7700.00 | Window Closed / Lapsed |