Silica powders for powder evacuated thermal insulating panel and method

Patent · 01 January 1994

OSTI ID:869675

Harris, Michael T ^[1]; Basaran, Osman A ^[2]; Kollie, Thomas G ^[2]; Weaver, Fred J ^[1]

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1. Knoxville, TN
2. Oak Ridge, TN

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2 /g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
• Assignee: Martin Marietta Energy Systems, Inc. (Oak Ridge, TN)
• Patent Number(s): US 5376449
• OSTI ID: 869675
• Country of Publication: United States
• Language: English

Related Subjects

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100
600
90
alcohol
alcohol solvent
ammonia
aqueous
aqueous slurry
ball-milled
cm
defined
defined internal
density
described
diameter
distilling
dried
evacuated
evacuated thermal
external
external porosity
external surface
insulating
insulating panel
insulating panels
internal
median
median size
method
nanometer
nanometer size
nanometers
obtainable
packing
packing density
panel
panels
particles
particles provide
porosity
porous
porous silica
pour
pour packing
powder
powder evacuated
powders
prepared
previously
provide
provide powder
r-values
range
reacting
reaction
recover
remove
resulting
resulting aqueous
significantly
silica
silica particles
silica powder
silica powders
silicate
size
slurry
solution
solvent
spherical
surface
tetraakyl
tetraakyl silicate
thermal
thermal insulating
water