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.degree. C.