Thermal stability and thermal expansion behaviour of ZrO₂/Y₂O₃ multilayers deposited by pulsed laser deposition technique

Multilayers of ZrO₂/Y₂O₃ were prepared by pulsed laser deposition technique with variation in the ZrO₂ layer thickness from 5 to 30 nm keeping the Y₂O₃ layer thickness constant (∼10 nm). The stability, phase evolution and thermal expansion behaviour of the multilayers were analyzed by high temperature x-ray diffraction technique, in the temperature range of 300–1373 K. Unlike the single layer of ZrO₂ film, which shows a mixture of tetragonal and monoclinic phase, the ZrO₂ layers in multilayers show tetragonal phase in case of all the multilayers investigated in the present work. The values of coefficient of thermal expansion (CTE) decrease with increase in the ZrO₂ layer thickness. The CTE of both ZrO₂ and Y₂O₃ are found to be influenced by their mutual solubility as well as due to interdiffusion of these oxides taking place along the interfaces of the multilayers, especially during high temperature heat-treatment. - Highlights: • ZrO₂/Y₂O₃ multilayers were deposited by pulsed laser deposition technique. • Formation of tetragonal phase of ZrO₂ and cubic phase of Y₂O₃ were observed. • The multilayers films show good thermal stability upto temperature 1373 K. • The coefficient of thermal expansion (CTE) of t-ZrO₂ decreases with increase in ZrO₂ layer thickness