Preparation of glass-ceramics in the MgO-Al2O3-SiO2 system via low-Temperature combustion synthesis technique

MgO-Al2O3-SiO2 (MAS) glass powders have been successfully synthesized by means of the low-temperature combustion technique using magnesium nitrate, aluminium nitrate and silicic acid as raw materials, and urea as fuel. The sintering behavior, crystallization process and dielectric properties of the MAS were investigated with DCS, XRD, TMA and SEM techniques. The results indicate that the sintering temperature of the as-prepared glass powders decreased with the addition of B2O3 and only alpha-cordierite was precipitated as a main crystal phase, i.e. without p-cordierite, for the glass powders heated at 1000 degrees C. Moreover, the as-prepared oc-cordierite exhibited a dense microstructure, the additive (B2O3 2.5 %) reducing the crystallization temperature of cc-cordierite phase from 1050 degrees C to 900 degrees C. The obtained cordierite-based glass-ceramics (sintered at 950 degrees C and 1000 degrees C) have a low dielectric constant (4.00-4.03 at 1 MHz), a low dielectric dissipation factor (= 0.003) and high sintering density (which is up to 98 % of the theoretical density). The properties of as-prepared MAS satisfy all requirements of a material for electronic packaging, making it a promising candidate for application as electronic packaging.