As a kind of wide band-gap material focused on in recent years, SnO2 thin Film with μm level has been widely applied in many fields such as solar cells, electric heating devices, transparent electrodes, and gas sensors, ect. This paper develops a real-time system to measure thermal expansion coefficients of SnO2 thin film, which can obtain directly surface morphology information of the samples. Micro-imaging and digital image correlation method is adopted to investigate the correlation by comparing the object surface image before deformation with that after deformation. Because of the lower demand for measurement environment and no damage to object, it’s easy to acquire on-line images, calculate synchronously and display real-time results. In the paper, thermal expansion coefficients of SnO2 thin film are determined in situ with change of the temperature. Both of ceramic and SnO2 thin film have shown anisotropy thermal expansion, thermal and residual stress appears between the ceramic substrate and SnO2 thin film as a result of thermal expansion coefficients mismatch. According to experimental results, the maximum stress values can be calculated between film and substrate and inside the substrate.
A DIFFERENTIAL DILATOMETER FOR RAPID DETERMINATION OF THERMAL EXPANSION COEFFICIENTS NEAR ROOM TEMPERATURE
