The effect of Cr2O3 doping on structures and dielectric constants of SiO2-Bi2O3-B2O3-Na2CO3 glass based on silica gel of natural sand

Abstract

One of the abundant natural resources along the coastal lines of Indonesia is silica sand. One of the beaches which has a lot of silica content is Bancar-Tuban beach. Silica can be used as a raw material of glass that has multiple properties in optic, dielectric, and other physical properties by introducing specific dopants. Some oxides have been used as dopant e.g. Al2O3, Fe3O4, and NiO. However, there has not been any comprehensive study discussing the multiple properties of natural silica-sand-based glass with Cr2O3 dopant so far. A series of samples have been prepared, which mean two solid steps to state melting technique. Cr2O3 was selected as a dopant due to its potential to control its color and to increase the dielectric constant of the glass. The synthesis of silica (SiO2) sand from BancarTuban beach was conducted through the sol-gel process. The composition varied as the addition of Cr2O3on 50SiO2-25B2O3-(6.5-x) Bi2O3-18.5Na2CO3-xCr2O3 (x = 0, 0.02, 0.04, 0.06 and 0.08mol), later called SBBN glass. The samples' characterizations of the structure and morphology were conducted through the use of XRD, and SEM-EDX. The measurements were done by using a DC capacitance meter in order to investigate the dielectric properties of the sample, under the influence of light. It is shown that addition of Cr2O3 did not alter the crystal structure but changed the structure of the functional bond formation. It is also revealed that the dielectric constant increased along with the increasing of Cr2O3. An interesting result was that the dielectric constant of the glass was quantized decreasingly as the increase of light.