Emulsion-char method for making fine ceramic powders
US4749664A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 1986 |
| Grant date | Jun 7, 1988 |
| Priority date | — |
| Expiry date | Dec 29, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2004/62
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Water soluble precursors of ceramic compounds are emulsified in an organic fluid containing an organic surfactant. The emulsion is subsequently mildly heated at a pressure of about 0.05 atmospheres to remove the free water from the emulsion droplets. The resulting sludge consists of particles deriving from the dehydrated emulsion droplets. These particles may only be bound by the surfactant, all or most of the original organic fluid having been boiling off under low pressure. This sludge is then heated in a standard air atmosphere to char the surfactant, which char is to maintain the separation between the dried droplet-derived particles to prevent forming sintered or fused agglomerates thereof. With continued heating the transient char is subsequently burned off and the particles are calcined to controllably and simply produce a fine ceramic powder of spherical particles having a narrow size distribution and an average size in the particularly useful range of 0.1 micron to 1.0 micron.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.