Al/Si比对SiO2-Al2O3-MgO系玻璃结构和性能的影响

SiO2-Al2O3-MgO系玻璃因具备强度大、弹性模量高等优异性能而用作高模量玻璃纤维的制备.采用熔融冷却法制备了不同Al/Si比的SiO2-Al2O3-MgO系基础玻璃,并研究了玻璃的结构和性能.红外光谱分析表明,玻璃网络结构由铝氧四面体[AlO4]和硅氧四面体[SiO4]相互连接而成.随着Al/Si比的增加,[AlO4]含量保持不变,[AlO6]含量逐渐增加.DSC分析表明,本系统玻璃的玻璃转变点Tg、成核温度Tx均随Al/Si比的增大而提高,玻璃的析晶倾向变强烈.热膨胀分析表明玻璃的热膨胀系数随Al/Si比的增大呈现先增大后减小的趋势.物理及机械性能测试结果如下:随Al/Si比的增大,密度、弹性模量均随之不断增大;而弯曲强度和维氏硬度则是持续降低.

Effect of Al/Si on Structure and Properties of SiO2-Al2O3-MgO Glass

SiO2-Al2O3-MgO glass is used to prepare high modulus glass fiber for its high strength and high modulus of elasticity. The SiO2-Al2O3-MgO based glasses with different Al/Si ratios were prepared by melt cooling method,and the structure and properties of the glass were studied. Infrared spectral analysis showes that the glass network structure is composed of [AlO4 ]and [SiO4 ]. With the increase of Al/Si ratio,the content of [AlO4 ]remaines unchanged,and the content of [AlO6 ]increases gradually. DSC analysis showes that the glass transition point Tg and nucleation temperature Tx increases with the increase of the Al/Si ratio,and the glass crystallization tendency becomes stronger. The thermal expansion analysis shows that the thermal expansion coefficient of glass increases firstly and then decreases with the increase of Al/Si ratio. The results of physical and mechanical properties are as follows:with the increase of Al/Si ratio,the density and elastic modulus increase as well,while the bending strength and the Vickers hardness decrease continuously.