Mono-crystalline Nanometer High Cristobalite Glass-ceramics from Nominal Pyroxene Glass

Transparent glass was prepared from nominal alkali pyroxene (Na 2 MgSi 2 O 6 ) composition. The results showed that the incorporation of Cr 2 O 3 in alkali pyroxene composition with 0.5 and 1.0 wt% increased the crystallization temperature of high cristobalite. High cristobalite was developed alone in all glass samples heat-treated at 800 °C. The microstructure shows nanometer crystals of high cristobalite which spread in glassy matrix. The density, hardness and coefficient of thermal expansion were between 2.49 and 2.53 g/cm 3 , 505 and 611 kg/mm 2 and between 9.38 and 13.32 × 10 − 6 °C − 1 (30–300 ˚C ), respectively for the three glass-ceramic compositions. All the samples have moderate to excellent antimicrobial activity on both gram positive bacteria ( Staphyllococus aureus ) and pathogenic fungal yeast ( Candida albicans ), which show broad spectrum antimicrobial activity toward bacteria and fungi, while the sample NMCr1 has an excellent antifungal activity only toward the pathogenic fungal yeast ( Candida albicans ), which was described as a promising antifungal agent.