US3873344A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ceramic treating process
Assignee: Kaman Sciences Corp
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Filing: 1973-05-21
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Granted: 1975-03-25
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Expires: 1993-05-21
Abstract
Abstract A new ceramic treatment process and product and, more particularly, a process for treating underfired porous partially vitrified relatively soft machinable refractory ceramic materials to produce hardened dimensionally stable end products at relatively low temperatures and the ceramic materials produced thereby which are suitable for application as bearings for undersea submergence, low temperature bearings for arctic vehicular and machinery applications, precision bearings for space use and liquid metal lubricated systems. The soft ceramics can be machined and shaped in the soft state and hardened by the process of this invention at temperatures well below normal vitrification temperatures with virtually no change in dimensions from the machined untreated ceramic to the treated and hardened end product. The present method comprises impregnating a ceramic oxide body with a solution of a chromium compound and heating the impregnated body to a temperature of at least 1,300*F which heating may precede or be preceded by impregnation and cure cycles of at least 600*F but less than the vitrification temperature of the ceramic oxide to harden the body.
Inventors
- 👤 Peter K Church
- 👤 Oliver J Knutson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:03
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/80; C04B41/81; C04B41/89; C04B33/00; C04B33/32; C04B35/00; C04B35/01; C04B35/10; C04B35/111; C04B35/622; C04B35/64; C04B41/45; C04B41/50; C04B41/5025; C04B41/5033; C04B41/85; C04B41/87; F; F02; F02B; F02B75/00; F02B75/02; F02B2075/022; F02B2075/027
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
128 words
THE METHOD OF PRODUCING A CHEMICALLY HARDENED REFRACTORY CERAMIC BODY WHICH COMPRISES PROVIDING A CORE OF A POROUS UNDERFIRED PARTIALLY VITRIFIED MACHINABLE REFRACTORY CERAMIC OXIDE, IMPREGNATING SAID CORE WITH A SOLUTION OF A CHROMIUM COMPOUND WHICH COMPOUND IS CAPABLE OF BEING CONVERTED TO AN OXIDE ON BEING HEATED TO A TEMPERATURE OF AT LEAST 600*F AND, CURING SAID IMPREGNATED CORE AT LEAST ONCE BY RAISING THE TEMPERATURE THEREOF TO AT LEAST 600*F BUT LESS THAN THE VITRIFICATION TEMPERATURE OF THE CERAMIC OXIDE OVER A PERIOD OF TIME SUFFICIENT TO CONVERT THE CHROMIUM COMPOUND IMPREGNATED THEREIN TO AN OXIDE TO HARDEN THE CERAMIC WHEREIN AT LEAST ONE CURE CYCLE IS CARRIED OUT AT A TEMPERATURE OF AT LEAST 1,300*F BUT LESS THAN THE VITRIFICATION TEMPERATURE OF THE CERAMIC BODY.
Claim 2
Independent Claim
128 words
THE METHOD OF PRODUCING A CHEMICALLY HARDENED REFRACTORY CERAMIC BODY WHICH COMPRISES PROVIDING A CORE OF A POROUS UNDERFIRED PARTIALLY VITRIFIED MACHINABLE REFRACTORY CERAMIC OXIDE, IMPREGNATING SAID CORE WITH A SOLUTION OF A CHROMIUM COMPOUND WHICH COMPOUND IS CAPABLE OF BEING CONVERTED TO AN OXIDE ON BEING HEATED TO A TEMPERATURE OF AT LEAST 600*F AND, CURING SAID IMPREGNATED CORE AT LEAST ONCE BY RAISING THE TEMPERATURE THEREOF TO AT LEAST 600*F BUT LESS THAN THE VITRIFICATION TEMPERATURE OF THE CERAMIC OXIDE OVER A PERIOD OF TIME SUFFICIENT TO CONVERT THE CHROMIUM COMPOUND IMPREGNATED THEREIN TO AN OXIDE TO HARDEN THE CERAMIC WHEREIN AT LEAST ONE CURE CYCLE IS CARRIED OUT AT A TEMPERATURE OF AT LEAST 1,300*F BUT LESS THAN THE VITRIFICATION TEMPERATURE OF THE CERAMIC BODY.
Claim 3
Dependent Claim
31 words
The method of claim 1 wherein there are at least two impregnation and cure cycles and all of the cure cycles are carried out at a temperature of at least 1,300*F.
Claim 4
Dependent Claim
42 words
The method of claim 1 wherein there are at least two impregnation and cure cycles including one or more high temperature cure cycles of at least 1,300*F and one or more low temperature cycles of at least 600*F but less than 1,300*F.
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein the oxide body is aluminum oxide.
Claim 6
Dependent Claim
11 words
The method of claim 1 wherein the solution is chromic acid.
Claim 7
Dependent Claim
15 words
The method of claim 3 wherein the initial cure cycle is a high temperature cycle.
Claim 8
Dependent Claim
15 words
The method of claim 3 wherein the initial cure cycle is a low temperature cycle.
Claim 9
Dependent Claim
15 words
The method of claim 7 wherein the first five cure cycles are low temperature cycles.
Claim 10
Dependent Claim
15 words
The method of claim 7 wherein the first ten cure cycles are low temperature cycles.
Claim 11
Dependent Claim
16 words
The method of claim 6 where the cure cycles are alternately high and low temperature cycles.
Claim 12
Dependent Claim
16 words
The method of claim 7 where the cure cycles are alternately high and low temperature cycles.
Claim 13
Dependent Claim
66 words
In a process for hardening and densifying a ceramic body which includes the steps of impregnating said body with a chromium compound followed by a heat conversion of the chromium compound to an oxide, the improved method of hardening of same which comprises converting the chromium compound to an oxide at a temperature of at least about 1,300*F but below the vitrification temperture of said body.
Claim 14
Dependent Claim
66 words
In a process for hardening and densifying a ceramic body which includes the steps of impregnating said body with a chromium compound followed by a heat conversion of the chromium compound to an oxide, the improved method of hardening of same which comprises converting the chromium compound to an oxide at a temperature of at least about 1,300*F but below the vitrification temperture of said body.
Claim 15
Dependent Claim
33 words
The method of claim 12 wherein there are at least two impregnation and conversion steps and all of the compound conversions steps are carried out at a temperature of at least 1, 300*F.
Claim 16
Dependent Claim
48 words
The method of claim 12 wherein there are at least two impregnation and curing steps and includes one or more compound conversion steps at a temperature of at least 1,300*F and one or more compound conversion steps at a temperature of at least 600*F but less than 1,300*F.
Claim 17
Dependent Claim
12 words
The method of claim 12 wherein the ceramic body is aluminum oxide.
Claim 18
Dependent Claim
12 words
The method of claim 12 wherein the chromium compound is chromic acid.
Claim 19
Dependent Claim
18 words
The method of claim 14 wherein the initial compound conversion step is carried out at at least 1,300*F.
Claim 20
Dependent Claim
22 words
The method of claim 14 wherein the initial chromium compound conversion step is carried out at a temperature less than 1, 300*F.
Claim 21
Dependent Claim
21 words
The method of claim 18 wherein the first five chromium compound conversion steps are carried out at tEmperatures less than 1,300*F.
Claim 22
Dependent Claim
22 words
The method of claim 18 wherein the first ten chromium compound conversion steps are carried out at a temperature less than 1,300*F.
Claim 23
Dependent Claim
21 words
The method of claim 17 where the chromium compound conversion steps are carried out alternately at temperatures below and above 1,300*F.
Claim 24
Dependent Claim
21 words
The method of claim 18 where the chromium compound conversion steps are carried out alternately at temperatures below and above 1,300*F.
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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |