Microlaminate composites as thermal barrier coatings

At present, plasma-sprayed ZrO 2 coatings are used as thermal barrier coatings. Although these coatings exhibit excellent thermal barrier properties, their brittle behavior puts significant limitations on their use. Microlaminate composites offer an excellent alternative to sprayed ZrO 2 coatings because in such composites the thermal conductivity in the plane perpendicular to the laminate is markedly low. Moreover, the thermal conductivity can be tailored by choosing appropriate metal/metal, metal/ceramic combinations, as well as the thickness of individual layers. Presently, we are exploring the Ni/NiCoCrAlY and Ti/CoCrAlY microlaminate composites as thermal barrier coatings. The method of fabrication of these laminates and the measurement technique used to determine thermal diffusivity and thermal conductivity of these coatings will be discussed.