US4135012A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface treatment of zirconia ceramic
Assignee: Marathon Monitors Inc
•
Filing: 1977-04-25
•
Granted: 1979-01-16
•
Expires: 1997-04-25
Abstract
Abstract Smooth surfaces of impervious zirconia-base ceramics are chemically treated to produce micropitting and/or microcratering therein which enables durable adherence of metal coatings (e.g. of noble metal) applied thereon. Treatment involves contact of the smooth surfaces with liquid leachant selected from concentrated sulfuric acid, ammonium bisulfate, alkali metal bisulfate and mixtures thereof at a temperature of at least 250° C. Leached surface is contacted with hydrochloric acid to remove reaction residue comprising sulfate of metal elements including zirconium in the ceramic.
Inventors
- 👤 Yao-Sin Su
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:29
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/009; C04B41/53; C04B41/5338; C04B41/5353; C04B41/80; C04B41/91
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
130 words
A method of chemically micropitting and/or microcratering a smooth surface of an impervious zirconia-base ceramic comprising contacting said smooth surface with a liquid leachant selected from concentrated sulfuric acid, ammonium bisulfate, alkali metal bisulfate and mixtures thereof at a temperature of at least about 250° C. and for a time sufficient to effect micropitting and/or microcratering generally uniformly distributed throughout the microstructure of the resultant leached surface, removing said leached surface from contact with said leachant, contacting said leached surface with hydrochloric acid to effect removal from said leached surface of a residue thereon comprising sulfate of metal elements including zirconium in said ceramic, removing said leached surface from contact with the hydrochloric acid, and rinsing said leached surface with water to effect removal of acid residue from that surface.
Claim 2
Independent Claim
130 words
A method of chemically micropitting and/or microcratering a smooth surface of an impervious zirconia-base ceramic comprising contacting said smooth surface with a liquid leachant selected from concentrated sulfuric acid, ammonium bisulfate, alkali metal bisulfate and mixtures thereof at a temperature of at least about 250° C. and for a time sufficient to effect micropitting and/or microcratering generally uniformly distributed throughout the microstructure of the resultant leached surface, removing said leached surface from contact with said leachant, contacting said leached surface with hydrochloric acid to effect removal from said leached surface of a residue thereon comprising sulfate of metal elements including zirconium in said ceramic, removing said leached surface from contact with the hydrochloric acid, and rinsing said leached surface with water to effect removal of acid residue from that surface.
Claim 3
Dependent Claim
13 words
The method of claim 1 including agitating said leachant while contacting said surface.
Claim 4
Dependent Claim
26 words
The method of claim 1 including, upon removal from said leachant, rinsing the leached surface with water to effect removal of leachant residue from that surface.
Claim 5
Dependent Claim
24 words
The method of claim 1 including, upon removal from said leachant, mechanically removing part of the leachant and sulfate residues from the leached surface.
Claim 6
Dependent Claim
12 words
The method of claim 1 wherein the leachant is concentrated sulfuric acid.
Claim 7
Dependent Claim
44 words
The method of claim 5 wherein the temperature of the leachant is in the range of from 275° C. to the boiling point thereof and the time of contacting said surface with the leachant is in the range of from 0.5 to 5 hours.
Claim 8
Dependent Claim
24 words
The method of claim 1 wherein the leachant is a mixture of 5-25% by weight alkali metal bisulfate and the balance concentrated sulfuric acid.
Claim 9
Dependent Claim
13 words
The method of claim 7 wherein the alkali metal bisulfate is sodium bisulfate.
Claim 10
Dependent Claim
44 words
The method of claim 8 wherein the temperature of the leachant is in the range of from 275° C. to the boiling point thereof and the time of contacting said surface with the leachant is in the range of from 0.5 to 5 hours.
Claim 11
Dependent Claim
11 words
The method of claim 1 wherein the leachant is ammonium bisulfate.
Claim 12
Dependent Claim
12 words
The method of claim 1 wherein the leachant is alkali metal sulfate.
Claim 13
Dependent Claim
18 words
The method of claim 11 wherein the alkali metal sulfate is selected from sodium bisulfate and potassium bisulfate.
Claim 14
Dependent Claim
28 words
The method of claim 1 wherein the zirconia-base ceramic is a stabilized zirconia consisting essentially of 4-15 mol % stabilizer oxide and 96-85 mol % ZrO 2 .
Claim 15
Dependent Claim
21 words
The method of claim 1 wherein the stabilizer oxide is selected from oxide of magnesium, calcium, yttrium and rare earth metal.
Claim 16
Dependent Claim
30 words
The method of claim 1 wherein the micropitting and microcratering respectively comprises micropits and microcraters individually having dimensions thereacross in the respective ranges of about 0.5-25 μm and 10-100 μm.
Claim 17
Independent Claim
161 words
A method of improving adherence of a metal coating on an initially smooth surface of an impervious zirconia-base ceramic comprising contacting said smooth surface with a liquid leachant selected from concentrated sulfuric acid, ammonium bisulfate, alkali metal bisulfate and mixtures thereof at a temperature of at least about 250° C. and for a time sufficient to effect micropitting and/or microcratering generally uniformly distributed throughout the microstructure of the resultant leached surface, removing said leached surface from contact with said leachant, contacting said leached surface with hydrochloric acid to effect removal from said leached surface of a residue thereon comprising sulfate of metal elements including zirconium in said ceramic, removing said leached surface from contact with the hydrochloric acid, rinsing said leached surface with water to effect removal of acid residue from that surface, drying said leached surface, and forming a metal coating on said leached surface with the metal of said coating extending into the micropitting and/or microcratering of that surface.
Claim 18
Independent Claim
161 words
A method of improving adherence of a metal coating on an initially smooth surface of an impervious zirconia-base ceramic comprising contacting said smooth surface with a liquid leachant selected from concentrated sulfuric acid, ammonium bisulfate, alkali metal bisulfate and mixtures thereof at a temperature of at least about 250° C. and for a time sufficient to effect micropitting and/or microcratering generally uniformly distributed throughout the microstructure of the resultant leached surface, removing said leached surface from contact with said leachant, contacting said leached surface with hydrochloric acid to effect removal from said leached surface of a residue thereon comprising sulfate of metal elements including zirconium in said ceramic, removing said leached surface from contact with the hydrochloric acid, rinsing said leached surface with water to effect removal of acid residue from that surface, drying said leached surface, and forming a metal coating on said leached surface with the metal of said coating extending into the micropitting and/or microcratering of that surface.
Claim 19
Dependent Claim
18 words
The method of claim 13 wherein the stabilized zirconia contains less than 2 wt. % ordinary incidental impurities.
References Cited (Backward Citations)
US2401537A
Cited
US2872312A
Cited
US3116991A
Cited
US3078180A
Cited
FR1302486A
Cited
US3113855A
Cited
US3287143A
Cited
US3296012A
Cited
US3433680A
Cited
US3365317A
Cited
US3690921A
Cited
US3881944A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-01-15 | 1982-07-17 | 1983-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-15 | 1986-07-17 | 1987-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-15 | 1990-07-17 | 1991-01-16 | $7700.00 | Window Closed / Lapsed |