Processes for preparing color stable red-emitting phosphors
US10072206B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 2016 |
| Grant date | Sep 11, 2018 |
| Priority date | — |
| Expiry date | Oct 29, 2036 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K11/616
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Processes for preparing color stable red-emitting phosphors include contacting a complex fluoride phosphor of formula I with a first fluorine-containing oxidizing agent in gaseous form at a first temperature ranging from 200° C. to 700° C. to form a first product phosphor, contacting the first product phosphor in particulate form with a solution of a compound of formula II in aqueous hydrofluoric acid to form a treated phosphor, and contacting the treated phosphor with a second fluorine-containing oxidizing agent in gaseous form at a second temperature <225° C., AxMFy:MN4+ IAxMFy II wherein A is independently at each occurrence Li, Na, K, Rb, Cs or a combination thereof, M is independently at each occurrence Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof, x is absolute value of the charge of the MFy ion; and y is 5, 6 or 7.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.