Method for producing small hollow spheres

Patent · Tue Mar 24 04:00:00 EST 1981

OSTI ID:6208634

Dressler, J L; Koo, J C; Rosencwaig, A

A method for producing small hollow spheres of glass having an outer diameter ranging from about 100 mu to about 500 mu with a substantially uniform wall thickness in the range of about 5-20 mu . The method involves introducing aqueous droplets of glass-forming solution into a long vertical drop oven or furnace having varying temperature regions. In one embodiment, one of the temperature regions is lower than both the preceeding region and the subsequent region. One region utilizes a temperature of at least 200* C. Higher than the melting point of the glass-forming material in the solution and, for example, may be at least 3 times higher than the temperature of the preceeding region. In addition, there is a sharp temperature gradient between these regions. As each droplet of solution passes through a first region it forms into a gel membrane having a spherical shape and encapsulates the rest of the drop retained in the elastic outer surface and the water entrapped within diffuses rapidly through the thin gel membrane which causes more of the glass-forming material to go out of solution and is incorporated into the gel membrane causing it to grow in size and become hollow. Thus produced hollow glass sphere has a sphericity, concentricity, and wall uniformity of better than 5%. The sphere is capable of retaining material of up to at least 100 atmospheres therein over long periods of time. In one embodiment.

• Assignee: Department of Energy
• Patent Number(s): US 4257799
• OSTI ID: 6208634
• Country of Publication: United States
• Language: English

Related Subjects

060201* -- Fusion Fuels-- Fabrication & Testing-- (1980-1987)
36 MATERIALS SCIENCE
360601 -- Other Materials-- Preparation & Manufacture
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALKALI METAL COMPOUNDS
BORIC ACID
DIMENSIONS
FABRICATION
GLASS
HYDRATES
HYDROGEN COMPOUNDS
HYDROXIDES
INORGANIC ACIDS
LASER TARGETS
LITHIUM COMPOUNDS
LITHIUM HYDROXIDES
MICROSPHERES
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
POTASSIUM HYDROXIDES
SILICATES
SILICON COMPOUNDS
SODIUM COMPOUNDS
SODIUM SILICATES
SPHERES
TARGETS
THICKNESS
WATER