The Effect of Thermal Shock on the Thermal Conductivity of a Functionally Graded Material

Abstract

Functionally Graded Materials (FGMs) are known to be useful for reducing thermal stress in applications where high heat fluxes and large temperature gradients exist. Applications of this type are found primarily in aerospace, where nose caps, leading edges and engines will experience these types of severe thermal loading. The thermal conductivity of a Ni20Cr / 8% yttria-partially-stabilized-zirconia functionally graded 1.1 mm thick coating on a substrate of 403 stainless steel was measured. Thermal conductivity of the as-received coated specimen, then thermally shocked the specimen and measured thermal conductivity again. The measurements were done using an absolute, steady-state technique over a temperature range from 400 K to 1200 K. The specimen was thermally shocked by heating in a furnace to 475 K, then quenching in water at 295 K. Finally this chapter discusses the effect of moderate thermal shock on the thermal conductivity of the coating.