Fast firing method for ceramics

Patent metadata

Field	Value
Publication number	US-10000424-B2
Application number	US-201414196163-A
Country	US
Kind code	B2
Filing date	Mar 4, 2014
Priority date	Mar 8, 2013
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

A method for firing a green honeycomb ceramic body in a kiln may include heating the green honeycomb ceramic body in four stages. The first stage may include heating the green honeycomb ceramic body from room temperature to a first temperature that at a first heating rate that is greater than or equal to about 75° C./hr. The second stage may include heating the green honeycomb ceramic body from the first temperature to a second temperature at a second heating rate that is less than or equal to the first heating rate. The third stage may include heating the green honeycomb ceramic body from the second temperature to a hold temperature at a third heating rate that is less than or equal to the first heating rate. The fourth stage may include holding the green honeycomb ceramic body at the hold temperature to remove residual carbon.

First claim

What is claimed is:

1. A method for firing a green honeycomb ceramic body in a kiln, the method comprising:
a) heating the green honeycomb ceramic body from room temperature to a first temperature that is from about 250° C. to about 650° C. at a first heating rate that is from about 75° C./hr to about 125° C./hr; then
b) heating the green honeycomb ceramic body to a second temperature that is from about 650° C. to about 950° C. at a second heating rate that is less than or equal to the first heating rate; and
c) heating the green honeycomb ceramic body to a third temperature that is greater than the second temperature at a third heating rate that is less than or equal to the first heating rate,
wherein the green honeycomb ceramic body has a diameter of from about 9 inches to about 15 inches, and an aspect ratio of from about 0.50 to about 2.00.

2. The method of claim 1 , wherein the first heating rate is about 125° C./hr.

3. The method of claim 1 , wherein the first heating rate is about 75° C./hr.

4. The method of claim 1 , wherein the second heating rate is from about 10° C./hr to about 125° C./hr.

5. The method of claim 4 , wherein the third heating rate is from about 20° C./hr to about 100° C./hr.

6. The method of claim 1 , wherein the third heating rate is from about 20° C./hr to about 90° C./hr.

7. The method of claim 1 , further comprising:
d) holding the green honeycomb ceramic body at a hold temperature to remove residual carbon, wherein the green honeycomb ceramic body is held at the hold temperature for up to about 20 hours.

8. The method of claim 1 further comprising adjusting an oxygen level in step a) and step b) to be from about 4% to about 15% by volume of an atmosphere in the kiln.

9. The method of claim 1 further comprising adjusting an oxygen level in step c) to be from about 5% to about 13% by volume of an atmosphere in the kiln.

10. The method of claim 1 , wherein the oxygen level in step b) and step c) is higher than an oxygen level in step a).

11. The method of claim 1 , wherein the green honeycomb ceramic body has a diameter greater than about 12 inches.

12. The method of claim 1 , wherein the green honeycomb ceramic body is cylindrical and has a diameter of about 12 inches and a length of about 11 inches, and wherein the second heating rate is from about 50° C./hr to about 125° C./hr.

13. The method of claim 1 , wherein the green honeycomb ceramic body is cylindrical and has a diameter of about 13 inches and a length of about 12 inches, and wherein the second heating rate is from about 30° C./hr to about 75° C./hr.

14. The method of claim 1 , wherein the green honeycomb ceramic body is cylindrical and has a diameter of about 13 inches and a length of about 17 inches, and wherein the second heating rate is from about 30° C./hr to about 60° C./hr.

15. The method of claim 1 further comprising introducing steam into the kiln in steps a) through c), wherein an amount of steam is present during steps a) through c) at no more than about 30% by volume of an atmosphere in the kiln.

16. The method of claim 1 , wherein the green honeycomb ceramic body has a super addition organic load from about 5% by weight to about 50% by weight.

17. The method of claim 16 , wherein the green honeycomb ceramic body has a super addition organic load from about 25% by weight to about 50% by weight.

18. The method of claim 1 , wherein the green honeycomb ceramic body comprises one or more of talc, clay and graphite, wherein the talc comprises about 15% by weight to about 50% by weight, the clay comprises about 10% by weight to about 30% by weight, and the graphite comprises up to about 20% as a super-addition.

19. The method of claim 1 , wherein a cordierite honeycomb ceramic body is formed, the cordierite honeycomb ceramic body having a porosity of greater than about 55%.

20. The method of claim 1 , wherein a cordierite honeycomb ceramic body is formed, the cordierite honeycomb ceramic body having a porosity of from about 40% to about 60%.

21. A method for firing a green honeycomb ceramic body in a kiln, the method comprising:
a) heating the green honeycomb ceramic body from room temperature to a first temperature of from about 375° C. to about 500° C. at a first heating rate that is from about 90° C./hr to about 125° C./hr;
b) heating the green honeycomb ceramic body to a second temperature of from about 750° C. to about 850° C. at a second heating rate that is from about 20° C./hr to about 75° C./hr;
c) heating the green honeycomb ceramic body to a third temperature of from about 950° C. to about 1100° C. at a third heating rate that is less than or equal to the second heating rate; and
d) holding the green honeycomb ceramic body at a hold temperature to remove residual carbon,
wherein the green honeycomb ceramic body has a diameter of from about 9 inches to about 15 inches, and an aspect ratio of from about 0.75 to about 1.50.

22. The method of claim 21 , wherein the green honeycomb ceramic body is cylindrical and has a diameter of about 12 inches and a length of about 11 inches.

23. The method of claim 21 , wherein the green honeycomb ceramic body is cylindrical and has a diameter of about 13 inches and a length of about 12 inches, and wherein the second heating rate is from about 32° C./hr to about 75° C./hr.

24. The method claim 21 , wherein the green honeycomb ceramic body is cylindrical and has a diameter of about 13 inches and a length of about 17 inches, and wherein the second heating rate is about 50° C./hr.

25. The method of claim 21 , wherein the third heating rate is from about 20° C./hr to about 50° C./hr.

26. The method of claim 21 further comprising adjusting an oxygen level in step a) from about 4% to about 15% by volume of an atmosphere in the kiln.

27. The method of claim 21 further comprising adjusting an oxygen level in step b) and step c) to be from about 6% to about 15% by volume of an atmosphere in the kiln.

28. The method of claim 21 further comprising adjusting an oxygen level in step d) to be from about 7% to about 12% by volume of an atmosphere in the kiln.

29. The method of claim 21 further comprising introducing steam into the kiln in steps a) through c), wherein an amount of steam is present during steps a) through c) up to about 30% of an atmosphere in the kiln.

30. The method of claim 21 further comprising introducing steam into the kiln in step d), wherein an amount of steam is present during step d) from about 15% to about 45% of an atmosphere in the kiln.

31. The method of claim 1 wherein an oxygen level in step a) and step b) is from about 4% to about 15% by volume of an atmosphere in the kiln.

32. The method of claim 1 wherein an oxygen level in step c) is from about 5% to about 13% by volume of an atmosphere in the kiln.

33. The method of claim 21 wherein the oxygen level in step a) is from about 4% to about 15% by volume of an atmosphere in the kiln.

34. The method of claim 21 wherein the oxygen level in step b) and step c) is from about 6% to about 15% by volume of an atmosphere in the kiln.

35. The method of claim 21 wherein the oxygen level in step d) is from about 7% to about 12% by volume of an atmosphere in the kiln.

Assignees

• Corning Inc

Inventors

• Beall Douglas Munroe
• Bronfenbrenner David Jack
• Faber Margaret Kathleen
• Iyer Sriram Rangarajan
• Tepesch Patrick David
• Wing Douglas Richard

Classifications

• C04B38/0038

  by superficial sintering or bonding of particulate matter · CPC title

• C04B35/195

  Alkaline earth aluminosilicates, e.g. cordierite {or anorthite} · CPC title

• C04B2111/343

  Crack resistant materials · CPC title

• C04B38/0006 Primary

  Honeycomb structures (from one or more corrugated sheets by winding or stacking C04B38/0083) · CPC title

• C04B2235/9607

  Thermal properties, e.g. thermal expansion coefficient · CPC title