Method of preparing a ceramic porous body
US5695700A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 25, 1995 |
| Grant date | Dec 9, 1997 |
| Priority date | — |
| Expiry date | May 25, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D39/2075
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A ceramics porous body having high porosity as well as high strength is especially suitable for use as a filter for removing foreign matter from a fluid or as a catalytic carrier. The porous body has a porosity of at least 30% and comprises columnar ceramic grains having an aspect ratio of at least 3. In particular, the porous body comprises Si.sub.3 N.sub.4 grains, of which at least 60% are hexagonal columnar .beta.-Si.sub.3 N.sub.4 grains. The porous body further comprises at least one compound of a rare earth element in an amount of at least 1 volume % and not more than 20 volume % in terms of an oxide of the rare earth element, and optionally at least one compound of elements of the groups IIa and IIIb of the periodic table and transition metal elements in an amount of not more than 5 volume % in terms of an oxide of each element. A compact of mixed powder obtained by adding the compound powder of the rare earth element to silicon nitride powder is heat treated in a nitrogen atmosphere at a temperature of at least 1500.degree. C., to prepare the silicon nitride ceramic porous body.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.