Claims
- 1. A composition comprising a substrate and a polycrystalline layer of zeolite crystals wherein at least 99% of said zeolite crystals have at least one point between adjacent crystals that is .ltoreq.20 .ANG. and wherein at least 90% of said crystals have widths of from about 0.2 to about 100 microns and wherein at least 75% of said crystals have a thickness within 20% of the average crystal thickness.
- 2. A composition according to claim 1 wherein said substrate is a porous substrate selected from the group consisting of stainless steel, alumina, cordierite, mullite, titania, pyrex, silica, silicon nitride, silicon carbide, zeolite, carbon, graphite and mixtures thereof.
- 3. A composition according to claim 1 wherein said zeolite crystals are about 2 to about 100 .mu. thick.
- 4. A composition according to claim 3 wherein said zeolite crystal thickness ranges from about 5 to about 100 .mu..
- 5. A composition according to claim 1 wherein said substrate is a non-porous substrate selected from the group consisting of quartz, glass, borosilicate glasses, clay, metal, silicon, polymer, graphite, dense ceramic and mixtures thereof.
- 6. A composition according to claim 1 wherein said zeolite crystals exhibit a crystallographic preferred orientation ranging from about 1 to about 500.
- 7. A composition according to claim 6 wherein when said zeolite crystals are MFI crystals said zeolite crystals have a C-orientation within 30.degree. of the normal to the surface of said substrate.
- 8. A composition according to claim 2 wherein said substrate has a porosity of about 5 to about 70% and a pore size distribution of about 0.004 to 100 .mu..
- 9. A composition according to claim 1 wherein said substrate has an average roughness with an amplitude of less than 10 .mu.m with an aspect ratio of the roughness less than 1:1.
- 10. A composition according to claim 1 wherein said crystals have widths of about 2 to about 50 microns.
- 11. A composition according to claim 1 wherein said layer of zeolite crystals is selected from the group consisting of silicates, aluminosilicates, aluminophosphates, silicoalumino-phosphates, metalloaluminophosphates, stanosilicates, MFI, FAU, zeolite Y, zeolite X, MAX, LTA, CHA, AFI, AEL, BEA, EUO, FER, KFI, MOR, MEL, MTW, OFF, TON, AFS, AFY, APC, APD, MTN, MTT, AEL and mixtures thereof.
- 12. A composition according to claim 11 wherein said layer of zeolite crystals is a layer of MFI zeolite crystals.
- 13. A composition according to claim 1 wherein said zeolite layer has less than 1 Volume % voids.
- 14. A composition according to claim 13 wherein said zeolite layer has less than 0.5 Volume % voids.
- 15. A composition according to claim 1 wherein said zeolite layer has less than 10,000 defects of greater than 40 .ANG. per square inch.
- 16. A composition according to claim 1 wherein said composition has incorporated therein about 0.1 to about 10 wt % noble metal.
Parent Case Info
This is a Continuation-in-Part of U.S. Ser. No. 267,760 filed Jul. 8, 1994 and U.S. Ser. No. 483,343 filed on Jun. 7, 1995, now abandoned, which is a Continuation-in-Part of U.S. Ser. No. 267,760 filed Jul. 8, 1994, now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5100596 |
Haag et al. |
Mar 1992 |
|
Related Publications (1)
|
Number |
Date |
Country |
|
483343 |
Jun 1995 |
|
Continuation in Parts (2)
|
Number |
Date |
Country |
Parent |
267760 |
Jul 1994 |
|
Parent |
267760 |
Jul 1994 |
|