Influence of the real density and structure imperfection of hollow glass microspheres on the compression strength

► A new formula for calculating the compression strength of hollow glass microspheres was proposed. ► Chemical composition of HGM was analyzed. ► Imperfect structure was characterized by optical microscope. ► Structure defects were characterized by SEM after heat treating at 700 °C. ► Strength of samples with same structure coefficient increases with real density. In this paper, we simplified the factors that affect the compression strength of hollow glass microspheres theoretically. When the chemical composition of the hollow glass microspheres was determined, the real density was the only variable to decide the strength. We calculated the theoretical strength of sample – T, Tg1, Tg2, S, A and R according to their chemical composition and real density. The real strength of the hollow glass microspheres was much lower than the theoretical strength actually due to the structure imperfection. The structure defect was characterized by optical microscope and scanning electron microscope (samples for scanning electron microscope have been treated under 700 °C). The real strength “ P r” should be decided by the theoretical strength “ P” multipied by a structure coefficient “ φ”, which is related to the preparation technology closely. The sample-T was graded in grain size with a water separator to get samples with the same structure coefficient but varied in real density. The results of compression test proved that the strength increased with the real density.