Sinterability and mechanical properties of glass-ceramics in the system SiO2-Al2O3-MgO/ZnO

[EN] The sintering, crystallization and mechanical behavior of three glass compositions in the SiO-AlO-MgO/ZnO system were investigated. Partial substitution of MgO by ZnO causes a decrease in T, a slight increase in the crystallization temperature and improves sinterability. Cordierite and enstatite were crystallized in bulk glasses heat treated at 1000 °C. Addition of ZnO resulted in the crystallization of cordierite, willemite and gahnite for the heat treated bulk glasses and cristobalite, enstatite, gahnite and willemite for the sintered glass powders. The first phase to crystallize is the β-quartz solid solution at 850−900 °C for all compositions. The glass and glass-ceramic with ZnO had the lowest hardness and elastic modulus. There was no variation of fracture strength with composition. The glass-ceramic with ZnO had a similar wear resistance in comparison to the composition with higher MgO content.
The authors acknowledge the financial support from CAPES PDSE (grant n°88881.132583/2016-01), FINEP, CNPq, Fundação Araucária, UGF from Brazil for funding laboratory infrastructure and are thankful to ICV-Madrid-Spain and C-LABMU/UEPG for the use of the characterization facilities