Effects of Al2O3 addition on physical properties of diopside based glass–ceramics for LED packages

One of the main problems of currently used Al2O3/glass composites for LED (light emitting diode) packaging materials is deterioration of the heat emission property due to the lower thermal conductivity of glass. In the present study, glass frit of a CaO–MgO–SiO2 system of stoichiometric diopside composition with the addition of various amounts of Al2O3 was milled, pressed into pellets isostatically, and heat-treated to fabricate diopside-based glass–ceramics. Effects of microstructure and crystallinity of the diopside phase produced in the glass–ceramics on the thermal conductivity, thermal diffusivity, density, and specific heat capacity were analyzed as a function of Al2O3 addition to investigate the feasibility of utilizing diopside-based glass–ceramics in LED packaging applications.