Quartz Crystal Reinforced Silica Glass Obtained by Spark Plasma Sintering

Spark Plasma Sintering (SPS) presents a very low processing time when compared to conventional sintering methods. Such fast processing conditions allow it to control the grain size growth and preserve the powders distribution into the mold during sintering, which makes it possible to obtain graded and nano structured (using nano-powders) materials. High purity powders of vitreous silica and crystalline silica (alpha quartz) were sintered by the SPS process at temperature of 1350 degrees C, which is higher than the annealing temperature of vitreous silica and below the temperature of quartz fusion. Such investigation showed the possibility to obtain high purity SiO2 material, which is a composite of silica glass matrix reinforced with crystalline alpha-quartz powder at almost any combination of volume fraction of matrix/reinforced structure, with well controlled reinforced grain size. X-ray diffraction and density measurements show the possibility to manufacture a unique glass-ceramic material of controlled crystallinity and density.