Refractory coatings comprising unstabilized zirconia, silica, and, optionally,
zircon and/or mullite are disclosed herein. The unstabilized zirconia, silica,
and optional zircon and/or mullite are applied as a slurry onto ceramic substrates
such as silicon carbide and fired. The refractory coatings of the present invention
maintained good edge definition and color when applied to ceramic substrates and
subjected to temperatures over 1100 C.