An investigation of ceramic coatings for protection of SiC from high-temperature corrosion
Silicon carbide (SiC) ceramics are susceptible to corrosion by certain industrial furnace environments. this behavior would limit the use of SiC components in ceramic heat exchangers. Because oxide ceramics corrode substantially less in the same environments, ceramic coatings have been investigated for corrosion protection. Coatings with Al/sub 2/O/sub 3/, SiO/sub 2/, or ZrO/sub 2/ as the main constituent were applied to sintered alpha and recrystallized (CS101) SiC substrates. The coated specimens were thermally cycled between room temperature and 1200)degree)C as a test of adherence. Some coatings adhered better to the inherently rougher CS101 SiC;however, most coatings did not adhere to either substrate. Two Al/sub 2/O/sub 3/-based coatings developed cracks but remained intact during thermal cycling, and two ZrO/sub 2/-based coatings were adherent without cracks. These four coatings were subjected to corrosion testing at 1200)degree)C in an oxidizing atmosphere containing Ns/sub 2/CO/sub 3/. None of these four coatings exhibited the desired corrosion resistance in this test. Coated samples, however, corroded less than an uncoated sample, indicating that coatings can improve corrosion resistance. 19 figs., 7 tabs
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5185325
- Report Number(s):
- ORNL/TM-10606; ON: DE88007873
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
SILICON CARBIDES
CORROSION PROTECTION
ADHESION
ALUMINIUM OXIDES
COMPARATIVE EVALUATIONS
FURNACES
HEAT EXCHANGERS
HEAT RECOVERY
PROTECTIVE COATINGS
SILICA
THERMAL CYCLING
ZIRCONIUM OXIDES
ALUMINIUM COMPOUNDS
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
COATINGS
ENERGY RECOVERY
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
RECOVERY
SILICON COMPOUNDS
SILICON OXIDES
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
360205* - Ceramics
Cermets
& Refractories- Corrosion & Erosion
320304 - Energy Conservation
Consumption
& Utilization- Industrial & Agricultural Processes- Waste Heat Recovery & Utilization