Aqueous zirconia sol and method of preparing same
US5643497A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 1995 |
| Grant date | Jul 1, 1997 |
| Priority date | — |
| Expiry date | Jun 2, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01J13/00
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A stable aqueous sol of colloidal zirconia having lowered surface activity and useful for polishing semiconductors and the like, is prepared by a process comprising calcining a colloidal zirconia having a specific surface area of 10 to 400 m.sup.2 /g, a particle size of 20 to 500 nm and a dehydratable water content of 4 to 15% by weight at 400.degree. to 1,000.degree. C. to form a calcined zirconia having a dehydratable water content of 0.1 to 2% by weight, and pulverizing the calcined zirconia in the presence of a water-soluble acid or alkali in water, to form the stable sol of colloidal zirconia having a specific surface area of 5 to 200 m.sup.2 /g, a particle size of 20 to 1,500 nm and a dehydratable water content of 0.1 to 3% by weight. The stable sol of colloidal zirconia has a ZrO.sub.2 concentration of 5 to 80% by weight.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.