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