Supercritical fluid molecular spray film deposition and powder formation
US4582731A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 1, 1983 |
| Grant date | Apr 15, 1986 |
| Priority date | — |
| Expiry date | Sep 1, 2003 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB05D2401/90
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Solid films are deposited, or fine powders formed, by dissolving a solid material into a supercritical fluid solution at an elevated pressure and then rapidly expanding the solution through a short orifice into a region of relatively low pressure. This produces a molecular spray which is directed against a substrate to deposit a solid thin film thereon, or discharged into a collection chamber to collect a fine powder. Upon expansion and supersonic interaction with background gases in the low pressure region, any clusters of solvent are broken up and the solvent is vaporized and pumped away. Solute concentration in the solution is varied primarily by varying solution pressure to determine, together with flow rate, the rate of deposition and to control in part whether a film or powder is produced and the granularity of each. Solvent clustering and solute nucleation are controlled by manipulating the rate of expansion of the solution and the pressure of the lower pressure region. Solution and low pressure region temperatures are also controlled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.