Methods for forming ceramic honeycomb articles

Patent metadata

Field	Value
Publication number	US-9334191-B2
Application number	US-78994510-A
Country	US
Kind code	B2
Filing date	May 28, 2010
Priority date	May 28, 2010
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

Processes for manufacturing porous ceramic honeycomb articles are disclosed. The processes include mixing a batch of inorganic components with processing aids to form a plasticized batch. The batch of inorganic components include talc having d pt50 ≦10 μm, a silica-forming source having d ps50 ≦20 μm, an alumina-forming source having a median particle diameter d pa50 of less than or equal to 10.0 μm, and a pore former having d pp50 ≦20 μm. The plasticized batch is formed into a green honeycomb article and fired under conditions effective to form a porous ceramic honeycomb article comprising a cordierite crystal phase and having a microcrack parameter (Nb 3 ) of from about 0.05 to about 0.25. After firing, the green honeycomb article the porous ceramic honeycomb article is exposed to a microcracking condition, which increases the microcrack parameter (Nb 3 ) by at least 20%.

First claim

What is claimed is:

1. A process for manufacturing a porous ceramic honeycomb article, comprising:
mixing a batch of inorganic components comprising talc having d pt50 ≦10 μm, a silica-forming source having d ps50 ≦20 μm, an alumina-forming source having a median particle diameter d pa50 of less than or equal to 10.0 μm, and a pore former having d pp50 ≦20 μm, wherein d pp50 is a median particle diameter of the pore former, d ps50 is a median particle diameter of the silica-forming source, d pa50 is a median particle diameter of the alumina-forming source and d pt50 is a median particle diameter of the talc, with processing aids to produce a plasticized batch;
forming the plasticized batch into a green honeycomb article;
firing the green honeycomb article under conditions effective to form a porous ceramic honeycomb article comprising a cordierite crystal phase and having a microcrack parameter (Nb 3 ) of from about 0.05 to about 0.25;
subsequent to firing, exposing the porous ceramic honeycomb article to a microcracking condition, wherein after exposure to the microcracking condition, the porous ceramic honeycomb article comprises a microcrack parameter (Nb 3 ) is at least 20% greater than the microcrack parameter prior to exposure to the microcracking condition.

2. The process of claim 1 , wherein the batch of inorganic components further comprises clay having d pc50 ≦5 μm, wherein d pc50 is a median particle diameter of the clay.

3. The process of claim 1 , wherein the microcracking condition comprises a thermal cycle.

4. The process of claim 3 , wherein during the thermal cycle, the porous ceramic honeycomb article reaches a peak temperature of at least 400° C.

5. The process of claim 4 , wherein after the porous ceramic honeycomb article reaches the peak temperature, the porous ceramic honeycomb article cools at a rate of at least 200° C./hr.

6. The process of claim 3 , wherein the thermal cycle occurs after application of a washcoat to the porous ceramic honeycomb article.

7. The process of claim 1 , wherein the porous ceramic honeycomb article further comprises a coefficient of thermal expansion (CTE) of about 7.0×10 −7 /° C. to about 15.0×10 −7 /° C. over from about 25° C. to about 800° C. prior to exposure to the microcracking condition, and a coefficient of thermal expansion of about 1.0×10 −7 /° C. to about 10.0×10 −7 /° C. over from about 25° C. to about 800° C. after exposure to the microcracking condition.

8. The process of claim 1 , wherein the porous ceramic honeycomb article further comprises a d f of less than or equal to about 0.4 both before and after exposure to the microcracking condition.

9. The process of claim 1 , wherein the porous ceramic honeycomb article further comprises a surface porosity of about 38% to about 45% both before and after exposure to the microcracking condition.

10. The process of claim 1 , wherein 3.0 μm≦d pt50 ≦10.0 μm.

11. A process for manufacturing a porous ceramic honeycomb article, comprising:
mixing a batch of inorganic components with processing aids to produce a plasticized batch;
forming the plasticized batch into a green honeycomb article;
firing the green honeycomb article under conditions effective to form a porous ceramic honeycomb article comprising a cordierite crystal phase and having a microcrack parameter (Nb 3 ) of from about 0.05 to about 0.25;
subsequent to firing, exposing the porous ceramic honeycomb article to a microcracking condition that comprises heating the porous ceramic honeycomb article to a peak temperature of at least 400° C. and cooling the porous ceramic honeycomb article at a rate of at least 200° C./hr, wherein after exposure to the microcracking condition, the porous ceramic honeycomb article comprises a microcrack parameter (Nb 3 ) is at least 20% greater than the microcrack parameter prior to exposure to the microcracking condition.

12. The process of claim 11 , wherein the microcracking condition occurs after application of a washcoat to the porous ceramic honeycomb article.

13. The process of claim 11 , wherein the porous ceramic honeycomb article further comprises a coefficient of thermal expansion (CTE) of about 7.0×10 −7 /° C. to about 15.0×10 −7 /° C. over from about 25° C. to about 800° C. prior to exposure to the microcracking condition, and a coefficient of thermal expansion of about 1.0×10 −7 /° C. to about 10.0×10 −7 /° C. over from about 25° C. to about 800° C. after exposure to the microcracking condition.

14. The process of claim 11 , wherein the porous ceramic honeycomb article further comprises a d f of less than or equal to about 0.4 both before and after exposure to the microcracking condition, wherein d f =(d 50 −d 10 )/d 50 .

15. The process of claim 11 , wherein the porous ceramic honeycomb article further comprises a d f of less than or equal to about 0.3 both before and after exposure to the microcracking condition, wherein d f =(d 50 −d 10 )/d 50 .

16. The process of claim 11 , wherein the porous ceramic honeycomb article further comprises a d f of less than or equal to about 0.2 both before and after exposure to the microcracking condition, wherein d f =(d 50 −d 10 )/d 50 .

17. The process of claim 11 , wherein the porous ceramic honeycomb article further comprises a surface porosity of about 38% to about 45% both before and after exposure to the microcracking condition.

18. A process for manufacturing a porous ceramic honeycomb article, comprising:
mixing a batch of inorganic components with processing aids to produce a plasticized batch;
forming the plasticized batch into a green honeycomb article;
firing the green honeycomb article under conditions effective to form a porous ceramic honeycomb article comprising a cordierite crystal phase and having a microcrack parameter (Nb 3 ) of from about 0.05 to about 0.25, a coefficient of thermal expansion (CTE) of about 7.0×10 −7 /° C. to about 15.0×10 −7 /° C. over from about 25° C. to about 800° C., and a d f of less than or equal to about 0.4, wherein d f =(d 50 −d 10 )/d 50 ;
subsequent to firing, exposing the porous ceramic honeycomb article to a microcracking condition that comprises heating the porous ceramic honeycomb article to a peak temperature of at least 600° C. and cooling the porous ceramic honeycomb article at a rate of at least 200° C./hr, wherein after exposure to the microcracking condition, the porous ceramic honeycomb article comprises a microcrack parameter (Nb 3 ) at least 20% greater than the microcrack parameter prior to exposure to the microcracking condition, a coefficient of thermal expansion (CTE) of about 1.0×10 −7 /° C. to about 10.0×10 −7 /° C. over from about 25° C. to about 800° C., and a d f of less than or equal to about 0.4.

19. The process of claim 18 , wherein the microcracking condition occurs after application of a washcoat to the porous ceramic honeycomb article.

20. The process of claim 18 , wherein the porous ceramic honeycomb article further comprises a d f of less than or equal to about 0.3 both before and after exposure to the microcracking condition.

21. The process of claim 18 , wherein the porous ceramic honeycomb article further comprises a d f of less than or equal to about 0.2 both before and after exposure to the microcracking condition.

22. The process of claim 18 , wherein the porous ceramic honeycomb article further comprises a surface porosity of about 38% to about 45% both before and after exposure to the microcracking condition.

2

Assignees

• Miao Weiguo
• Wang Jianguo
• Corning Inc

Inventors

• Miao Weiguo
• Wang Jianguo

Classifications

• C04B2235/6562

  Heating rate · CPC title

• B01D39/2075

  sintered or bonded by inorganic agents · CPC title

• C04B38/0054

  the pores being microsized or nanosized · CPC title

• C04B2111/343

  Crack resistant materials · CPC title

• C04B2235/3217

  Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina · CPC title