为了提高微晶玻璃原料中高钙冶金渣的掺量,需要制备出碱度更高的微晶玻璃. 本文采用一步法,以钢渣为主要原料,制备碱度( CaO与SiO2的质量比)为0. 9的钢渣基高碱度微晶玻璃. 通过X射线衍射分析、扫描电镜和性能测试等手段,研究热处理条件对微晶玻璃微观形貌及线收缩率、体积密度和抗折强度等性能的影响规律. 研究表明,高碱度微晶玻璃适合采用一步法制备工艺,当在1100℃保温120 min时,微晶玻璃烧结过程基本完成,此时获得最大体积密度2. 4 g·cm-3 ,最高抗折强度56. 4 MPa. 微晶玻璃的主晶相为钙铝黄长石,副晶相为辉石. 基础玻璃颗粒在升温过程中完成了成核和析晶过程,而在保温过程中主要进行的是基础玻璃颗粒的烧结致密化和晶体的进一步发育. 升温至1100℃保温30 min,微晶玻璃的抗折强度超过45 MPa,微晶玻璃内部晶体呈方柱状交织排列并构成晶体骨架分布在残余的玻璃基体中;随着保温时间的增加,微晶玻璃的线性烧结收缩率、体积密度和抗折强度均逐渐增大,而晶相的含量基本保持不变,晶体逐渐由球形颗粒状和短柱状发育为长柱状. 晶体的形状以及与残余玻璃相构成的整体致密结构是导致高碱度微晶玻璃力学性能提高的主要因素.
High basicity ( CaO/SiO2 mass ratio) glass-ceramics were prepared to improve the usage of high calcium metallurgical slags in raw materials. Glass-ceramics with a high basicity of 0. 9 were prepared using steel slag as the main raw material through one-step sintering process. The influences of heat treatment on the microstructure, linear shrinkage, bulk density and bending strength of glass-ceramics were investigated by X-ray diffraction, scanning electron microscopy and performance testing. The results show that one-step sintering process is suitable for preparing high basicity glass-ceramics. The sintering process of the glass-ceramics is basically completed after heat treatment at 1100℃ for 120 min, with the largest bulk density of 2. 4 g·cm-3 and the optimal bending strength of 56. 4 MPa. The main crystalline phase of the glass-ceramics is gehlenite and the secondary crystalline phase is augite. The nucleation and crystallization process is completed in the heating process, while in the heat preservation process the sintering densification and crystal growth are dominant. After heating to 1100℃ and holding for 30 min, the bending strength of the glass-ceramics exceeds 45 MPa. Columnar crystals are intertwined together to form the crystal skeleton which constitutes the microstructure with residual glass phase inside the glass-ceramics. Besides, the linage shrinkage, bulk density and bending strength of the glass-ceramics increase with the increasing of holding time. The crystal morphology transforms from spherical particles and short columns into long rod-like columns with the increasing of holding time, while the crystalline phase content stays constant. The crystal morphology of the glass-ceramics and the integrated dense microstructure formed by the crystals and the residual glass phase are two primary factors of the improvement in mechanical properties of the glass-ceramics.