High-temperature nanoindentation for temperature-dependent mechanical behavior of enamel coating

High temperature may cripple the properties of enamel coatings, even lead to the microcracking nucleation and spalling from substrates. Therefore, a comprehensive understanding of high temperature properties of enamel is vital for assessing its service life and reliability. In this paper, we investigate the high temperature mechanical properties of enamel coating by nanoindentation, such as the hardness, elastic modulus and creep. The results show that the hardness of enamel coatings decreases with the increase of temperature. However, the elastic modulus of enamel coatings exhibits anomalous increase with temperature. In addition, by analyzing the creep depth, the stress exponent and activation energy of creep can be obtained. The activity energies below and above the glass transition temperature are found to be different.