Claims
- 1. A process for firing ceramic materials to produce fired ceramic products having a density of at least 98% of theoretical density, said process comprising introducing a shaped article comprising ceramic particles and binder therefor into a burnout oven and subjecting the shaped article in the burnout oven to a temperature of 700.degree. to 1600.degree. C. for a time sufficient to at least substantially remove said binder without firing the ceramic materials, and to create gaseous products of burning said binder and a substantially binder free shaped article comprising particles; separating said gaseous product from said binder free shaped article; thereafter firing the substantially binder free shaped article in a closed kiln, while at least substantially preventing gaseous products of burning the binder in the burnout oven from entering the kiln, said firing in said kiln being at a temperature of 800.degree. to 1600.degree. C. under an atmosphere, consisting essentially of oxygen at a pressure of at least one-half atmosphere gauge, for a time sufficient for said particles to sinter; and then normally allowing said fired shaped article to cool in ambient air; whereby to form ceramic, oxide products whose bulk density is at least about 98% of the theoretical density of said ceramic oxide shaped article.
- 2. A process for firing a shaped article comprising ceramic particles to produce a fired ceramic shaped article having a density of at least 98% of theoretical density, said process comprising firing the shaped article comprising ceramic particles at a temperature of 800.degree. to 1600.degree. C. in a closed kiln having an atmosphere consisting essentially of oxygen at a pressure of at least one-half atmosphere gauge, and wherein the firing is conducted for time sufficient for said ceramic particles to sinter and then normally allowing said sintered shaped article to cool in ambient air; whereby to form dense ceramic oxide shaped articles whose bulk density is at least about 98% of the theoretical density of said ceramic oxide shaped article.
- 3. A process as claimed in claim 1 carried out continuously in a tunnel furnace.
- 4. A process as claimed in claim 1 carried out under said atmosphere consisting essentially of oxygen having an overall pressure of up to about 2 atmospheres, gauge.
- 5. A process as claimed in claim 1 wherein said ceramic particles comprise particles which are not substantially adversely affected by contact with oxygen at elevated pressure and elevated temperature.
- 6. A process as claimed in claim 1 wherein said ceramic particles consist essentially of a composition which is not substantially adversely affected by contact with oxygen at elevated pressure and elevated temperature.
- 7. A process as claimed in claim 2 carried out continuously in a tunnel furnace.
- 8. A process as claimed in claim 2 carried out under said atmosphere consisting essentially of oxygen having an overall pressure of up to about 2 atmospheres, gauge.
- 9. A process as claimed in claim 2 wherein said ceramic particles comprise particles which are not substantially adversely affected by contact with oxygen at elevated pressure and elevated temperature.
- 10. A process as claimed in claim 2 wherein said ceramic particles consist essentially of a composition which is not substantially adversely affected by contact with oxygen at elevated pressure and elevated temperature.
- 11. In the process of forming a ceramic shaped article sinter comprising:
- subjecting a shaped article, comprising particles of ceramic material and a binder therefore, to a temperature of 700.degree. to 1600.degree. C. in the burnout oven for a time sufficient to at least substantially remove said binder without firing the ceramic particles; and thereby
- creating gaseous products of burning said binder and a substantially binder free shaped article comprising particles;
- separating said gaseous products of burning from said binder free shaped article;
- thereafter firing the substantially binder free shaped article in a closed kiln, while preventing any substantial amount of gaseous products of burning the binder in the burnout oven from entering the kiln; and then
- cooling said fired shaped article to form a ceramic product article;
- the improvement, of forming a ceramic article of high bulk density of at least 98% of the theoretical density of said sinter components, which comprises:
- firing said substantially binder free article in said kiln at a temperature of 800.degree. to 1600.degree. C. under an atmosphere consisting essentially of oxygen at a pressure of at least one-half atmosphere gauge, for a time sufficient for said particles to sinter; and then
- allowing said fired shaped article to cool under ambient air;
- whereby forming a ceramic, oxide product whose bulk density is at least about 98% of the theoretical density of the components of said ceramic oxide shaped article.
- 12. In the process of forming a ceramic shaped article sinter comprising:
- firing a shaped article comprising ceramic particles at a temperature of 800.degree. to 1600.degree. C. in a closed kiln having an atmosphere comprising oxygen to form a ceramic oxide shaped article; and then
- cooling said ceramic oxide shaped article to form a ceramic article product;
- the improvement, of forming a ceramic article of high bulk density of at least 98% of the theoretical density of said sinter components, which comprises:
- firing said substantially ceramic article in said kiln at a temperature of 800.degree. to 1600.degree. C. under an atmosphere consisting essentially of oxygen at a pressure of at least one-half atmosphere gauge, for a time sufficient for said particles to sinter; and then
- allowing said fired shaped article to cool under ambient air;
- whereby forming a ceramic, oxide product whose bulk density is at least about 98% of the theoretical density of the components of said ceramic oxide shaped article.
- 13. A process of increasing the bulk density of a sintered ceramic article which comprises:
- forming a shaped article of ceramic particles;
- sintering said shaped article at a temperature of about 800.degree. to 1600.degree. C. under an atmosphere consisting essentially of oxygen at a pressure of at least one-half atmosphere gauge, for a time sufficient to sinter said particles into a ceramic oxide shaped article having a bulk density of at least about 98% of the theoretical density of the components of said ceramic oxide shaped article; and then
- allowing said sintered ceramic oxide shaped article to cool in ambient air.
Parent Case Info
This application is a continuation-in-part of application Ser. No. 08/013,472 filed Jan. 29, 1993 now abandoned, which is a division of application Ser. No. 149,174 filed Jan. 27, 1988, now U.S. Pat. No. 4,533,302, is a continuation of application Ser. No. 304,293 filed Jan. 31, 1989, now abandoned which is a continuation, now abandoned division of application Ser. No. 07/745,973, filed Aug. 12, 1991.
US Referenced Citations (7)
Divisions (1)
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Number |
Date |
Country |
Parent |
149174 |
Jan 1988 |
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Continuations (3)
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Number |
Date |
Country |
Parent |
13472 |
Jan 1993 |
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Parent |
745973 |
Aug 1991 |
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Parent |
304293 |
Jan 1989 |
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