Er_2O_3对锂锌硅微晶玻璃热膨胀及力学性能的影响

Effect of Er_2O_3 on Thermal Expansion and Mechanical Propertyies of Lithium Zinc Disilicate Glass-ceramics

使用晶化法制备以二硅酸锂为主晶相,P_2O_5为主要形核剂的锂锌硅微晶玻璃。引入稀土Er_2O_3掺杂Li_2OSiO_2-P_2O_5-ZnO系统基础玻璃。通过测试该系统微晶玻璃的差热曲线、X射线衍射图谱、高温粘度曲线和扫描电镜图像,研究引入Er_2O_3含量的变化对该系统微晶玻璃析晶性能、次晶相的种类和含量、高温粘度变化、析出晶粒的大小及分布情况和微晶玻璃抗弯强度的影响。结果表明:引入Er_2O_3提高该系统微晶玻璃的玻璃转化温度,提高锂锌硅微晶玻璃晶化热处理的温度,影响了次晶相偏硅酸锂晶相的析出,通过改变微晶玻璃次晶相的种类和含量,降低了体系的热膨胀系数,掺杂0.3%的Er_2O_3提高了二硅酸锂的析晶速率,并降低了该系统微晶玻璃的高温粘度,当Er_2O_3的掺杂量为0.3%时,该体系微晶玻璃获得最大的抗弯强度310 MPa。

A lithium zinc disilicate glass-ceramic was obtained by crystallization,using lithium disilicate as the primary crystalline phase and P_2O_5 as the main nucleation agent.The rare earth Er_2O_3 was added to the Li_2O-SiO_2-P_2O_5-ZnO system base glass.The differential thermal analysis,X-ray diffraction,high temperature viscosity,and scanning electron microscopy were used for the glass-ceramic system,in order to study how the amount of Er_2O_3 added affect the crystallization behavior,high temperature viscosity,flexural strength of the glass-ceramic,the type and quantity of the secondary crystalline phase,and grain sizes and distribution of precipitated crystals.The experimental results reveal that addition of Er_2O_3 in the system can lower the glass transition temperature of the lithium zinc silicate glass-ceramic,increase the threshold crystallization temperature and affect the precipitation of lithium metasilicate.The type and quantity of the secondary crystalline phase have changed after addition of this additive,and thereby thermal expansion coefficient of the system decreases.0.3% addition of Er_2O_3 is found to be able to accelerate the precipitation of lithium disilicate and decrease the high temperature viscosity of the lithium silicate glass-ceramic.When the content of this additive is 0.3%,the glass-ceramic's flexural strength reaches peak value of 310 MPa.