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US3765855A
Expired / Lapsed
US
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Electro-ionic method of strengthening glass
Assignee: United States Department of the Navy
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Filing: 1971-12-30
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Granted: 1973-10-16
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Expires: 1991-12-30
Abstract
Abstract A process for strengthening glass comprising (1) subjecting one face of sodium or lithium containing glass at a temperature above its annealing point to a current from a molten salt to affect replacement of sodium or lithium ions by larger ions, (2) repeating step (1) but using a molten sodium or lithium salt and allowing current to flow for a time greater than the time to be used in steps (3) and (5) combined; (3) subjecting the opposite face of the glass as in step (1) but with the current reversed, (4) chill-tempering the glass and (5) repeating step (3) but at a temperature which is below the strain point of the glass.
Inventors
- 👤 B Larrick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:10
CPC Classifications
C; C03; C03C; C03C21/00
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
41 words
The method of claim 1 wherein the larger cations which are used to replace the cations selected from the group consisting of lithium, sodium and mixtures thereof, are selected from the group consisting of sodium, potassium, copper, silver and mixtures thereof.
Claim 2
Dependent Claim
56 words
replacing at least part of said larger cations introduced into said glass in step (1) with smaller cations and simultaneously replacing at least part of the cations selected from the group consisting of lithium, sodium and mixtures thereof which are originally present in said glass with the larger cations introduced into the glass in step (1),
Claim 3
Dependent Claim
27 words
replacing on the face of the glass opposite that treated earlier the cations selected from the group consisting of sodium, lithium and mixtures thereof with larger cations;
Claim 4
Dependent Claim
11 words
The method of claim 2 wherein said larger cations are potassium.
Claim 5
Dependent Claim
24 words
The method of claim 1 wherein the charge transfer of step (2) is greater than the charge transfer of steps (3) and (5) combined.
Claim 6
Dependent Claim
4 words
chill-tempering said glass and;
Claim 7
Dependent Claim
90 words
replacing at least part of the small cations selected from the group consisting of lithium, sodium and mixtures thereof which were originally present in said glass with the larger cations introduced into the glass in step (3) and simultaneously replacing at least part of the larger cations introduced into the glass in step (3) by more larger cations; wherein steps 1-3 are performed at a temperature above the annealing temperature of the glass and below the softening point and step 5 is performed below the strain point of the glass.
Claim 8
Dependent Claim
24 words
The method of claim 2 wherein the charge transfer of step (2) is greater than the charge transfer of steps (3) and (5) combined.
Claim 9
Dependent Claim
24 words
The method of claim 3 wherein the charge transfer of step (2) is greater than the charge transfer of steps (3) and (5) combined.
Claim 10
Dependent Claim
22 words
The method of claim 4 wherein the charge transfer of step (2) is about three times the charge transfer of step (1).
Claim 11
Dependent Claim
22 words
The method of claim 5 wherein the charge transfer of step (2) is about three times the charge transfer of step (1)
Claim 12
Dependent Claim
22 words
The method of claim 6 wherein the charge transfer of step (2) is about three times the charge transfer of step (1).
Claim 13
Dependent Claim
17 words
The method of claim 4 wherein the charge transfer of steps (3) and (5) are about equal.
Claim 14
Dependent Claim
17 words
The method of claim 5 wherein the charge transfer of steps (3) and (5) are about equal.
Claim 15
Dependent Claim
17 words
The method of claim 6 wherein the charge transfer of steps (3) and (5) are about equal.
Claim 16
Dependent Claim
17 words
The method of claim 7 wherein the charge transfer of steps (3) and (5) are about equal.
Claim 17
Dependent Claim
17 words
The method of claim 8 wherein the charge transfer of step (3) and (5) are about equal.
Claim 18
Dependent Claim
17 words
The method of claim 9 wherein the charge transfer of steps (3) and (5) are about equal.
Claim 19
Dependent Claim
22 words
The method of claim 10 wherein the charge transfer of step (3) is about equal to the charge transfer of step (1).
Claim 20
Dependent Claim
22 words
The method of claim 11 wherein the charge transfer of step (3) is about equal to the charge transfer of step (1).
Claim 21
Dependent Claim
22 words
The method of claim 12 wherein the charge transfer of step (3) is about equal to the charge transfer of step (1).
Claim 22
Dependent Claim
22 words
the method of claim 13 wherein the charge transfer of step (3) is about equal to the charge transfer of step (1).
Claim 23
Dependent Claim
22 words
The method of claim 14 wherein the charge transfer of step (3) is about equal to The charge transfer of step (1).
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) | 1976-10-15 | 1977-04-16 | 1977-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-15 | 1981-04-16 | 1981-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-15 | 1985-04-16 | 1985-10-16 | $7700.00 | Window Closed / Lapsed |