A multilayered
ceramic topcoat of a
thermal barrier coating system is useful for high temperature corrosive applications such as hot section components in gas
turbine engines. The
ceramic topcoat includes at least two
layers, each having generally columnar grain microstructures with different
grain orientation directions. A preferred method of producing the multilayered
ceramic topcoat includes positioning a
superalloy substrate at a first angled orientation relative to a ceramic
vapor cloud in an
electron beam
physical vapor deposition apparatus for a time sufficient to grow a first ceramic layer. The substrate is then reoriented to a second, different angled orientation for a time sufficient to grow a second ceramic layer. The ceramic
layers exhibit columnar microstructures having respective
grain orientation directions which are related to the first and second substrate orientations. For uniformly
coating a complex contoured surface such as a
turbine blade airfoil, the blade can be rotated during
coating deposition at each angled orientation. Alternatively, the article may be continuously reoriented according to a predetermined speed cycle to produce generally arcuate, sinusoidal,
helical, or other columnar grain microstructures.