Thermal deformation of Y2O3 partially stabilized ZrO2 coatings by digital image correlation method

A contact-free method based on the digital image correlation (DIC) technology has been established to measure the in-plane thermal deformation of yttria stabilized zirconia (YSZ) bulk and YSZ free-standing coatings prepared by electron beam physical vapor deposition (EB-PVD). The results show a superb test agreement between the DIC method and the mechanical dilatometer. Moreover, thermal strain of the sintered YSZ bulk as well as the coatings caused by phase transformation of monoclinic-tetragonal phase after 15 h thermal exposure at 1450 °C are determined by the DIC method. The volumetric changes induced by the phase transformation of YSZ coatings are measured during heating and cooling, which are helpful for understanding the stress state and lifetime prediction of thermal barrier coating (TBC) system.