The mechanical properties of MgO-CaO-Al2O3-SiO2 composite glass

Glasses with composition in the quaternary phase field of the MgO-CaO-Al2O3-SiO2 (MCAS) system were prepared by the sol-gel method. X-ray diffraction studies of specimens sintered at a temperature higher than 940 °C showed that cordierite and anorthite existed as two different phases. The flexural strength of the sintered MCAS specimens increased critically as the sintering temperature was decreased below 940 °C and increased slightly as the sintering temperature increased above 940 °C. For MCAS composites glass sintered at 940 °C the flexural strength also increased slightly with the sintering time. By calculation using the equation δ = δ0 exp(−np) (where n, p, δ, and δ0 are a constant value, pore fraction, strength of the porous body, and strength of the non-porous body), the flexural strength of non-porous MCAS composite glass was found to be about 200 MPa.