粉末烧结法制备α-堇青石基玻璃陶瓷的析晶动力学和性能

在堇青石化学计量组分和非堇青石化学计量组分中分别添加B₂O₃, 通过玻璃粉末烧结法制备玻璃陶瓷,并研究了玻璃陶瓷的性能, 包括非等温析晶动力学、热学、力学和介电性能。本研究使用非堇青石化学计量组分制备了α-堇青石基玻璃陶瓷, 并加入B₂O₃促进α-堇青石析出, 提高MgO-Al₂O₃-SiO₂玻璃的结晶能力。玻璃成分中过量的MgO和SiO₂不会影响玻璃的析晶能力, 但会影响析晶的类型; 增加B₂O₃含量可以制备低热膨胀系数的α-堇青石基玻璃陶瓷, 但会降低玻璃陶瓷的软化点。此外, 增加B₂O₃含量还可以提高玻璃陶瓷的致密性和强度。α-堇青石基玻璃陶瓷的最大抗弯强度、弹性模量、断裂韧性和体积密度分别为(42.4±3.0) MPa、(34.0±2.9) GPa、(0.7±0.15) MPa?m^1/2和1.53 g/cm³。制备的α-堇青石基玻璃陶瓷表现出良好的介电性能(介电常数低至3.5), 热膨胀系数低至4.22×10^-6 K^-1。

Crystallization Kinetics,Properties of α-cordierite Based Glass-ceramics Prepared by Glass Powder Sintering

The resulting glass-ceramics were prepared by glass powder sintering using stoichiometric and non-stoichiometric cordierite components with addition of B₂O₃. Properties of the glass-ceramics, including the non- isothermal crystallization kinetics, thermal, mechanical and dielectric properties were investigated. The α-cordierite based glass-ceramics can be easily prepared by using non-stoichiometric cordierite components, and B₂O₃ addition can promote the precipitation of α-cordierite and improve the crystallization ability of the MgO-Al₂O₃-SiO₂ glass. Moreover, rich MgO and SiO₂ in the glass composition did not affect the crystallization ability of the glass, but affect the type of precipitated crystal phase. The increase of B₂O₃ addition can prepare α-cordierite based glass-ceramics with a low coefficient of thermal expansion (CTE), but it also lower its softening point. In addition, the increase of B₂O₃ addition can also improve the compactness and mechanical strength of the glass-ceramics. The maximum flexural strength, elastic moduli, fracture toughness and bulk density of α-cordierite based glass-ceramics are (42.4±3.0) MPa, (34.0±2.9) GPa, (0.7±0.15) MPa·m^1/2, and 1.53 g/cm³, respectively. And the as-prepared α- cordierite based glass-ceramics show good dielectric properties (? as low as 3.5) with a low CTE of 4.22 × 10^-6 K^-1.