Synthesis and characterization of [BaO-(10-x)ZrO2-TiO2-SiO2-xCrO3] type glass and glass ceramics.

Various glass compositions were prepared in a glassy system [25BaCO₃-(10-x) ZrO₂-20TiO₂-45SiO₂-xCrO₃] (x = 0, 2, 4, and 6) using melt-quenching technique. XRD patterns of glass and glass ceramics showed amorphous and crystalline nature. Density of glass and glass ceramics decreased from 3.4553 to 3.4381 g/cm³ and 3.7485 to 3.1977 g/cm³ with increasing concentration of CrO₃. DTA of the glasses revealed a shift in base line which suggests a change in specific heat and attributed to the glass transition temperature, T_g. FTIR and Raman spectroscopic analysis indicated that an increasing doping of CrO₃ changes structural network by increasing number of nonbridging oxygens (NBO) within glassy matrix. These results revealed that bands toward low frequency side endorsed to the vibration of Ba²⁺ metal cation, bending vibration of Si-O-Si and bonding formation of ZrO₂. Concentration of CrO_3, changed the microsture significantly and hence, a denser, fully developed mixed morphology was noticed with spherical grains of ZrO₂, irregular shape of bazirite (BaZr_0.97Ti_0.03Si₃O₉) phase and TiO₂ grains. Glass ceramic sample BZTS6C971 CrO₃ (x = 6) retains high value of dielectric constant, ~4555 due to space charge polarization. Hence, these glass ceramics might be useful for diverse applications such as in optical devices, electronic circuits, and multilayer ceramic capacitors. [ABSTRACT FROM AUTHOR]