There is provided a novel thermal barrier coating material which does not
have a problem of phase transition, whose melting point is higher than
its working temperature range, whose thermal conductivity is smaller than
that of zirconia, and whose thermal expansion coefficient is greater than
that of zirconia. The thermal barrier coating material comprises as a
main component, a composition having an orthorhombic or monoclinic
structure derived from perovskite (for example, a tabular perovskite
structure expressed by the composition formula A.sub.2B.sub.2O.sub.7), or
a tetragonal layer structure having a c axis/a axis ratio equal to or
greater than 3 (for example, a K.sub.2NiF.sub.4 structure, a
Sr.sub.3Ti.sub.2O.sub.7 structure, or a Sr.sub.4Ti.sub.3O.sub.10
structure), a composition expressed by the composition formula
LaTaO.sub.4, or a composition having an olivine type structure expressed
by the composition formula M.sub.2SiO.sub.4 or (MM').sub.2SiO.sub.4
(where M, M' are divalent metal elements).