Ceramic compositions
US5385874A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1993 |
| Grant date | Jan 31, 1995 |
| Priority date | — |
| Expiry date | Aug 26, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P70/50
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A solid composition provides high oxygen ion conductivity, and includes a metal oxide combined with multiple dopants. The oxide may, for example, include zirconia, bismuth trioxide, thoria or hafnia. The dopants are chosen such that they are of similar ionic radius to the oxide, but such that they generally have different valences. For example, zirconium has a +4 valence, while dopants are usually chosen which have +2 or +3 valences. Possible dopants include materials such as magnesia, yttria, and oxides of calcium, barium, strontium, lanthanum, ytterbium, and scandium. It has been found that choosing the dopants such that they exist in the composition at specified ratios results in surprising ability to transport oxygen ions. In the case of a composition which includes magnesia and yttria dopants placed within a zirconia matrix, it has been found desirable to maintain the ratio of the mole percentages of the magnesia to the yttria in the range of from about 5.75:10 to about 11:10. Also disclosed are methods and apparatus for using the composition in removing oxygen and water from a mixture of gases. Such a process is valuable in the isolation and purification of both oxygen and th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.