Measurement of Microscale Residual Stresses in Single-Phase Ceramics and the Relationship Among Residual Stress, Ordering Degree, and Microwave Dielectric Loss

A methodology is provided for characterizing the distribution of residual stresses at the grain level in α-PbO2-type structural Mg1+xTi0.7Sn0.3Nb2O8 using micro-Raman spectroscopy. The Raman-shift analysis reveals non-uniform residual tensile stress at high spatial resolution. Moreover, the average Raman spectra confirm that the ratio of intensity at 298cm -1to 281cm -1 can be used as an indicator to characterize the ordering degree of the α-PbO2-type structure. On this basis, the relationship among residual stress, ordering degree, and microwave dielectric loss is summarized, that grains with higher ordering degree possess larger residual stresses which lead to the increase of lattice anharmonicity and hence increase the microwave dielectric loss. Thus, the microwave dielectric loss depends strongly on residual stresses, which are often neglected.