Preparation of lanthanum chromate and lanthanum chromite powders by sol-gel
US4830780A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1987 |
| Grant date | May 16, 1989 |
| Priority date | — |
| Expiry date | Oct 23, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E60/50
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
This invention relates to a process for the preparation of a crystalline compound having an empirical formula LaCr.sub.x A.sub.1-x O.sub.4 yH.sub.2 O where A is a metal selected from the group consisting of Mg, Sr, Ca and Ba, x ranges from 0.99 to about 0.7 and y ranges from 0 to 0.15. The process comprises adding a solution of the appropriate metal salts to a solution of ammonium hydroxide thereby precipitating a hydroxide gel intermediate, which is dried and calcined in air to yield the resultant crystalline compound which has a huttonite structure. Additionally, this invention relates to a process for the preparation of a ceramic powder having the empirical formula LaCr.sub.x A.sub.1-x O.sub.3, where A is a metal selected from the group consisting of Mg, Sr, Ca and Ba, and x ranges from 0.99 to about 0.7. Finally, a ceramic composition having the empirical formula LaCr.sub.x A.sub.1-x O.sub.4 yH.sub.2 O having a huttonite structure is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.