Comparison of liquidus temperature of E-glass by uniform temperature method and heating stage microscope

Abstract

Liquidus temperature (T[subscript L]) is a glass property that is difficult to determine or calculate. T[subscript L] of binary and ternary systems can be found in phase diagram but not available for multicomponent systems such an industrial glass. The furnace temperature control basing on an excess of T[subscript L] data from approximation will increase unnecessary energy used. In this work, series of glass in system of E-Glass and ECR-Glass were fabricated from chemical grade oxides. The effects of addition of alkali oxides (12 and 3 wt% of Na [subscript 2[O and K[subscript 2]O on T[subscript L] were study. T[subscript L] was measured using two different methods which were a uniform temperature method and heating stage microscope. The reference standard glass and standard aluminum were used to assess the accuracy of the furnace and the heating stage used respectively. It was found that T [subscript L] measured by the uniform temperature method was higher than that measured by heating stage about 115 degrees celsius. In addition, first order polynomial function was used to model an equation for predcting T [subscript L] relate to component concentrations. The major primary crystalline phases detected by optical microscope, XRD and SEM/EDX were wollastonite and anorthite. The study of effect of alkali oxides on T [subscript L] was noticed that K[subscript 2]O containing glasses tended to have higher T[subscript L] compared to Na[subscript 2]O containing glasses. Addition of alkali oxides led to crystallization of wollastonite crystals. T [subscript L] of industrial glass composition was 1085 degrees Celsius while the simulated glasses showed higher T [subscript L]. The variation0-1.3 wt% of iron oxide in this glass compositions showed the T [subcript L] tended to decrease slightly with increasing of concentration of iron oxide