Study On Composition And Properties Of Low-boron E Glass

E glass, because its good electrical insulating properties and mechanicalproperties, is not only wildly used in production of electrical insulating glass fiber butalso in production of glass fiber reinforced materials. B2O3is one of the mostimportant raw materials of glass fiber preparation which cost is up to more than halfof all the cost of raw material. It is volatile of B2O3in the process of glass melting thatwill cause not only the composition change of glass, but also the environmentalpollution. So it is very important to study the relation between composition andproperties and to search the way to improve the performance of low-boron E glass.In this study, the basic glass composition is based on the composition of originalcomposition of E glass and glass is prepared by melt quenching method. Structure isstudied by IR spectrum analysis. The phase after crystallization of glass is studied byXRD diffraction analysis. The viscosity of glass melt is measured by using rotaryviscometer. Density of glass is measured by the Archimedes method. Chemicalstability is tested by the powder method.Results showed that while replacing CaO by B2O3in glass, also boron is mainlyexisted as [BO3] units entering main structure of glass, which contribute to thedecreasing of high temperature viscosity, but CaO, as the modifier of glass, still has agreater effect in decreasing viscosity, the viscosity of glass melt is still increased. It isa increasing of density, chemical stability and devitrification temperature while thecontent of B2O3decreased. The main composition of crystal phase after crystallizationis changed through the content decreasing of CaSiO3and increasing of CaAl2Si2O8.Replacing Al2O3by SiO2caused an approximately increase of high temperatureviscosity. At the beginning of the replacing these is a decreasing of viscosity, becauseof the decreasing of non-bridging oxygen that from [AlO4], and it is more obviouslyat a higher temperature because of a larger activation energy at this composition. TheXRD result shows that by the replacing of SiO2, the main crystal of devitrificationphase is turned anorthite into wollastonite. The water resistance has a little bitchanged stronger. At the beginning of replacing, the acid resistance becomes strongerand alkali resistance is weaker, and then both of them grow weaker.The increasing of MgO content leads to the decreasing of viscosity and increasingof crystallization temperature, on the contrary the increasing of SrO content leads tothe increasing of viscosity and decreasing of crystallization temperature. The maincrystal phase after crystallization when replacing MgO is Ca(Mg,Al)(Si,Al)2O6 diopside and CaAl2Si2O8anorthite, when replacing SrO is CaAl2Si2O8anorthite andCa3(Si3O9) Pseudo wollastonite. Based on the result of experiments, there is a obviouscontrary change compared with the main trend of glass properties and performancewhile the content of replacing by MgO is3~6%, and the content of SrO is around4.5%. Because of the complicated composition and structure, the reason of the strangepoint is still need to be studied.