云母/莫来石可加工微晶玻璃的制备与析晶

通过调整SiO2-MgO-Al2O3-K2O-F基础玻璃的组成和热处理条件,制备了云母/莫来石复合可加工微晶玻璃.应用扫描电子显微镜和X射线衍射技术研究了可加工微晶玻璃的析晶特征.结果表明:添加3.0;ZnO(质量分数)的基础玻璃析出了锌尖晶石相,而锌尖晶石的析出抑制莫来石相的形成,没有得到云母/莫来石复合材料.当玻璃中添加3.0;的V2O5后,在试样中同时析出莫来石和云母晶体,但没有形成莫来石/云母复合的组织.含V2O5 8.0;的玻璃在等温析晶中,从表面析出莫来石和粗大枝状的云母晶体,云母间相互交错程度较低,只有在随炉升温的情况下,云母晶体以莫来石相为核心异质生长,形成均匀分布的云母/莫来石复合微晶玻璃材料.

Preparation and Crystallization of Machinable Mica/Mullite Glass-ceramic

The machinable mica/mulllite(Al6Si2O13) composites glass-ceramic in the SiO2-MgO-Al2O3-K2O-F glass system was prepared through adjusting the additive composition and controlling the thermal treatment schedules.The crystallization behaviors were investigated by scanning electron microscope and X-ray diffraction measurements.Results indicate that the incorporation of 3.0% ZnO in mass fraction induces the crystallization of gahnite(ZnAlSiO4) phase,which suppresses the forming of mullite(Al6Si2O13) phase and the microstructure of mica/mullite composites are not observed.While in the glass with 3.0% V2O5,still no mica/mulllite composites glass-ceramics are found,though the crystalline phases of mica and mullite are both identified by XRD.In the glass sample with 8.0%V2O5 dopent,the crystalline phases of mullite and mica are participated at the surface-layer in the isothermal treatment,in which the mica crystals appear coarse dendrite shapes and have less interlocking.However,in the non-isothermal treatment,the mica crystals grow through epitaxial processes on the mullite crystals and finally the homogeneously distributed mica/mullite composites are formed.