Protective coating for alumina-silicon carbide whisker composites

Patent · Sun Jan 01 00:00:00 EST 1989

OSTI ID:867000

Tiegs, Terry N ^[1]

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1. Lenoir City, TN

Ceramic composites formed of an alumina matrix reinforced with silicon carbide whiskers homogenously dispersed therein are provided with a protective coating for preventing fracture strength degradation of the composite by oxidation during exposure to high temperatures in oxygen-containing atmospheres. The coating prevents oxidation of the silicon carbide whiskers within the matrix by sealing off the exterior of the matrix so as to prevent oxygen transport into the interior of the matrix. The coating is formed of mullite or mullite plus silicon oxide and alumina and is formed in place by heating the composite in air to a temperature greater than 1200.degree. C. This coating is less than about 100 microns thick and adequately protects the underlying composite from fracture strength degradation due to oxidation.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4839316
• OSTI ID: 867000
• Country of Publication: United States
• Language: English

Related Subjects

protective
coating
alumina-silicon
carbide
whisker
composites
ceramic
formed
alumina
matrix
reinforced
silicon
whiskers
homogenously
dispersed
therein
provided
preventing
fracture
strength
degradation
composite
oxidation
exposure
temperatures
oxygen-containing
atmospheres
prevents
sealing
exterior
prevent
oxygen
transport
interior
mullite
plus
oxide
heating
air
temperature
1200
degree
100
microns
thick
adequately
protects
underlying
due
dispersed therein
protective coating
ceramic composites
ceramic composite
silicon carbide
silicon oxide
carbide whiskers
microns thick
oxygen-containing atmosphere
fracture strength
carbide whisker
containing atmosphere
sites formed
-silicon carbide
matrix reinforced
/428/427/501/