Structure, elastic modulus, and thermal expansion of MgO-Al2O3-B2O3-SiO2 glasses with Al2O3 substitution for B2O3 based on experiments and molecular dynamics simulations

LL Zhang and ZQ Qian and JH Fu and WK Gao and XZ Dong and H Chen and Y Tang and YY Li and YL Yue and JF Kang, CERAMICS INTERNATIONAL, 51, 48944-48954 (2025).

DOI: 10.1016/j.ceramint.2025.08.141

The effects of substituting Al2O3 for B2O3 on the structure, coefficient of thermal expansion (CTE), and elastic modulus (E) of MgO- Al2O3-B2O3-SiO2 glass were investigated through experiments and molecular dynamics simulations. The results showed that E of the samples increased obviously, while CTE decreased by replacing B2O3 with Al2O3. And the simulated properties exhibited a good trend agreement with the experiments. The increase in the sum of AlO4, AlO5, and AlO6 units, as well as the rise in the ratio of the sum of AlO5 and AlO6 to AlO4, led to the formation of more tri-cluster oxygen through edge- sharing with the glass network units. This change increased the dissociation energy and atomic packing density of MgO-Al2O3-B2O3-SiO2 glass, thereby increasing E of the samples. The reduced layered BO3 structure leads to stronger, more compactness connected bonds in the glass network. This restricts ion anharmonic vibrations as temperature rises, reducing the CTE. The CTE and E of sample with the maximum substitution were 2.299 ppm/degrees C and 86.73 GPa, respectively, meeting the requirements for Si chip packaging.

Return to Publications page