Perpustakaan Digital ITB

Glass is a versatile material widely used in housewares, construction, and automotive industries due to its transparency, thermal and chemical stability, formability, and recyclability. The Na?O-CaO-SiO? system dominates conventional glass production, while sodium calcium silicate glass-ceramics are increasingly valued for combining glassy and crystalline properties, enabling applications in architecture, photovoltaics, biomedical engineering, optics, and radiation shielding. Recent studies revealed that Na?CaSiO?, previously regarded as stoichiometric, can form solid solutions, allowing adjustment of composition and physical properties. X-ray diffraction (XRD) plays a significant role in characterizing the structure of these materials, particularly in determining the defects and disorder. This study investigates Na?CaSiO? synthesized by equilibration and furnace cooling to clarify its crystal structure, phase stability, and validate solid solution formation. In this study, Na?CaSiO? was synthesized through equilibration at 1200 °C for 48 hours using high-purity SiO?, CaCO?, and Na?CO?, with excess Na?CO? added to compensate for volatilization of Na2O at the equilibration temperature. The mixtures were homogenized, equilibrated in a muffle furnace, and cooled before analysis. Powder XRD confirmed the formation of the Na?CaSiO?, as well as other equilibrium phases. Further analysis of the powder diffraction pattern provided the lattice parameters and the space group of each phase, which was corroborated by single-crystal XRD (SC-XRD) measurement. Na?CaSiO? solid solution was successfully synthesized using furnace cooling, with both quenching and slow cooling producing similar behavior and confirming its stability. Na?CaSiO? has a cubic crystal structure with the space group of Fm-3m. The lattice parameters obtained from powder diffraction are a = 7.48508(11), 7.27936(31), 7.48332(11), and 7.30841(55) Å for SLS2050, SLS2025, SLS4050, and SLS4025, respectively. Measurement of a suitable single crystal selected from the SLS4050 sample confirmed the space group as Fm-3m with a lattice parameter of a = 7.4954(4) Å. An inverse linear relationship was observed between Na?O content and lattice parameters, with higher Na?O concentration leading to smaller lattice dimensions.