【摘要】 以MgO -Al2 O3-SiO2 -Li2 O -R2 O -F(R =Na,K)为基础玻璃组成 ,研究了晶化工艺条件对锂云母微晶玻璃热膨胀性能的影响 .结果表明 :10 5 0℃以上 ,在相同保温时间下 ,热膨胀系数随着晶化温度的升高而下降 ,其值在 30 .6× 10 - 7～ 5 7.9× 10 - 7℃ - 1 ( 2 0～ 5 0 0℃ )间变化 ,较好满足低膨胀材料 ( 30× 10 - 7～ 6 0× 10 - 7℃ - 1 )的封接要求 .热膨胀系数随晶化温度的升高而下降 ,其原因是 β锂辉石低膨胀相少量增加和微孔及微裂纹的增加引起宏观膨胀量减少共同作用的结果 .在晶化温度不变的情况下 ,增加保温时间具有和提高晶化温度相同的效果 .根据实际应用要求 ,材料性能可以在热膨胀系数、抗弯强度和切削性能三者之间加以优化更多还原

【Abstract】 s: Effects of crystallization process on thermal expansion property of lepidolite glass_ceramics of MgO-Al 2O 3-SiO 2- Li 2O- R 2O-F(R=Na, K) system were studied. The results show that the thermal expansion coefficient of lepidolite glass_ceramics decreases with the increase of crystallization temperature above 1 050 ℃. Prolonging heat_treatment time has the same effect as crystallization temperature. The reasons are attributable to the increases in β _spondumene, which has low thermal expansion coefficient, and micropores and microcracks in the glass_ceramics, which lead to low macroscopic thermal expansion. The thermal expansion coefficients are varied from 31.0×10 -7 to 57.9×10 -7 ℃ -1 (20-500 ℃). Besides, the results also reveal that the properties of thermal expansion coefficient, bending strength and machinability can be optimized according to application demand.更多还原