Compositional design of high modulus glasses for disk substrates

Modified equations have been derived on the basis of Makishima–Machenzie (M–M) theory for direct determination of the elastic modulus of glasses from composition. This modified calculation model gives an excellent agreement between the measured and estimated values of elastic modulus for over 50 different glasses. Using this model we developed a glass in the Li2O–MgO–Al2O3–Y2O3–TiO2–SiO2 system with elastic modulus value greater than 130 GPa and bending strength higher than 50 kg f/mm2. This high modulus glass substrate is expected to provide a solution to the vibration problem of rapid rotation magnetic disk and allow higher track density per inch to be achieved for high performance hard-disk drives (HDDs).