Process for producing sub-micron ceramic powders of perovskite compounds with controlled stoichiometry and particle size
US5112433A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 9, 1988 |
| Grant date | May 12, 1992 |
| Priority date | — |
| Expiry date | Dec 9, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/497
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for making a crystalline ceramic powder having a perovskite structure, ABO.sub.3, that includes the steps of preparing a first acidic solution containing one or more elements selected from the group consisting of hafnium, zirconium, titanium, niobium, tantalum, uranium, iron, antimony, lanthanum, bismuth, thorium, indium, nickel, manganese, neodymium, samarium, cobalt, tungsten, tin, vanadium, dysprosium, praseodymium, yttrium, promethium, europium, cerium, ytterbium, lutetium, scandium, gadolinium, terbium, holmium, erbium, thulium, chromium, potassium, and lithium; preparing a second basic solution containing a sufficient concentration of hydroxide to provide a predetermined pH when mixed with the first solution; adding the first acidic solution to the second basic solution to precipitate a substantially pure mixture of hydroxides; washing the precipitate to remove hydroxide and salt impurities that solubilize lead or other constituent elements of the powder; preparing an aqueous slurry of the washed precipitate and adding oxides or hydroxides of one or more of the elements selected from the group consisting of barium, strontium, calcium, magnesium, lead, zinc, yttrium,…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.