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Title: Method for producing small hollow spheres

Abstract

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. Thusmore » 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.« less

Inventors:
; ;
Publication Date:
OSTI Identifier:
6208634
Patent Number(s):
US 4257799
Application Number:
TRN: 81-015011
Assignee:
Department of Energy
Resource Type:
Patent
Resource Relation:
Patent File Date: Filed date 26 Jul 1979; Other Information: PAT-APPL-061167
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 36 MATERIALS SCIENCE; LASER TARGETS; FABRICATION; MICROSPHERES; BORIC ACID; GLASS; HYDRATES; LITHIUM HYDROXIDES; POTASSIUM HYDROXIDES; SODIUM SILICATES; SPHERES; THICKNESS; WATER; ALKALI METAL COMPOUNDS; DIMENSIONS; HYDROGEN COMPOUNDS; HYDROXIDES; INORGANIC ACIDS; LITHIUM COMPOUNDS; OXYGEN COMPOUNDS; POTASSIUM COMPOUNDS; SILICATES; SILICON COMPOUNDS; SODIUM COMPOUNDS; TARGETS; 060201* - Fusion Fuels- Fabrication & Testing- (1980-1987); 360601 - Other Materials- Preparation & Manufacture

Citation Formats

Dressler, J L, Koo, J C, and Rosencwaig, A. Method for producing small hollow spheres. United States: N. p., 1981. Web.
Dressler, J L, Koo, J C, & Rosencwaig, A. Method for producing small hollow spheres. United States.
Dressler, J L, Koo, J C, and Rosencwaig, A. Tue . "Method for producing small hollow spheres". United States.
@article{osti_6208634,
title = {Method for producing small hollow spheres},
author = {Dressler, J L and Koo, J C and Rosencwaig, A},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1981},
month = {3}
}