玻璃组成对Li_2O–Al_2O_3–SiO_2微晶玻璃热膨胀系数的影响(英文)

通过传统熔融法制备了具有低膨胀系数的Li2O-Al2O3-SiO2(LAS)微晶玻璃.利用扫描电镜、X射线衍射、差热分折及热膨胀系数测定等分 析手段,研究了玻璃组成中Li2O,Al2O3,SiO2的含量对微晶玻璃热膨胀系数的影响.结果表明:在标准样品的基础上,Li2O的含量对热膨胀系数影 响很大:Li2O的含量提高,由于形成β-锂辉石,微晶玻璃的结晶程度增加与晶粒尺寸增大,导致热膨胀系数增大.与此相比较,Al2O3和SiO2成分 的变化对膨胀系数的影响较小.当玻璃组成(质量分数,下同)为4%～6%Li2O,16%~18%Al203,66%~68%Si02时,Li2O-Al2Oy-SiO2玻璃的膨胀 系数为-1.5～1.5×10-7/℃(0~700℃)

INFLUENCE OF COMPOSITION ON THE COEFFICIENT OF THERMAL EXPANSION OF Li_2O-Al_2O_3-SiO_2 GLASS-CERAMIC

Li2O-Al2O3-SiO2 (LAS) system glass-ceramics were prepared by the conventional melting method. The influences of the contents of Li2O, Al2O3 and SiO2 on the coefficient of thermal expansion (CTE) of the glass-ceramic were investigated by scanningB electronic microscopy, X-ray diffraction and differential thermal analysis. The results show that the content of Li2O plays a predomi- nant role in the CTE of the glass-ceramic. The CTE increases obviously with the increase of Li20 content due to the formation of β-spodumene and as a result, the crystal size and crystallinity in the LAS glass increase. Comparatively, the influence of the contents of SiO2 and A1203 on CTE is weaker. The Li2O-Al2O3-SiO2 glass-ceramics with a basic composition (in mass), 4%-6% Li2O, 16%-18% Al2O3 and 66%-68% SiO2, have a CTE range from -1.5 × 10-7 to 1.5 × 10-7/℃ (0-700 ℃).