High pH colloidal dispersion of a cerium compound, and a process for its preparation
US5922330A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1995 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | Sep 12, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/40
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
In a first embodiment of the invention, a colloidal dispersion of a cerium compound is characterised in that it has a pH of at least 4 and a conductivity of at most 5 mS/cm. In a second embodiment, the colloidal dispersion is characterised in that it has a pH of more than 5. In a third embodiment, the colloidal dispersion is characterised in that the colloids have a carbon content such that the carbon/cerium mole ratio is at Least 0.01 and in that the pH is greater than 5. A process for the preparation of these dispersions is characterised in that a first colloidal dispersion is used as a starting material, with a pH which is lower than the pH of the dispersion which is to be prepared, and the pH of the first dispersion is raised while reducing the ionic strength. For the third embodiment, an organic acid is added to the starting dispersion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.