Method of preparing rare earth pyrohafnate phosphors
US4014812A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 19, 1975 |
| Grant date | Mar 29, 1977 |
| Priority date | — |
| Expiry date | May 19, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K11/7766
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Phosphors having the general formula (A.sub.1.sub.-x RE.sub.x).sub.2 Hf.sub.2 O.sub.7 are disclosed wherein A is selected from the group consisting of yttrium, gadolium, lanthanum, scandium and lutetium; RE is selected from the group consisting of praseodymium, samarium, europium, terbium, dysprosium, holmium, erbium and thulium; and x is from about 0.001 to 0.10. The phosphors are prepared by dissolving an oxide of A and an oxide of RE in a mineral acid and dissolving HfOCl.sub.2 in water and combining the two solutions. A precipitating agent such as oxalic acid is added and the precipitate is washed, dried and fired to produce the phosphors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.