Study of crystallization, microstructure and mechanical properties of lithium disilicate glass-ceramics as a function of the sintering temperature
DOI:
https://doi.org/10.14295/bds.2021.v24i2.2378Abstract
Objective: The purpose of the present study was to synthesize and characterize lithium disilicate glass-ceramics through the Li2 O-SiO2 system for determining the most satisfactory sintering parameter by evaluating the crystalline composition, microstructure and mechanical properties. Material and methods: The glass-ceramics were prepared from a glass precursor by means of the melting/cooling technique with a composition of 33.33 Li2 O and 66.67 SiO2 (mol.%). The specimens were compressed by the uniaxial pressing technique and three different thermal treatments were used for sintering: 850 °C (Group 1), 900 °C (Group 2), and 950 °C (Group 3), which were determined based on the differential scanning calorimetry (DSC) result. The glass-ceramics were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Archimedes method, microhardness and biaxial flexural strength analyses. Results: The results regarding XRD predominantly showed lithium disilicate phase for all the heat treatments performed. Moreover, grains with a needle form were more predominantly observed in the SEM images for Group 3, as well as a higher densification and consequently higher mechanical properties. In contrast, Group 1 presented the lowest mechanical properties and densification, as well as the highest porosity. Conclusion: The present study demonstrated how extremely important it is to follow the heat treatment recommended by the manufacturers of ceramics, including time and temperature, which possess direct effects in the crystalline phase formation, as well as in the material’s microstructure and mechanical properties.
Keywords
Crystallization; Glass-ceramics; Lithium disilicate.
References
Alkadi L, Ruse ND. Fracture toughness of two lithium disilicate dental glass ceramics. J Prosthet Dent 2016;116:591–6. doi:10.1016/j.prosdent.2016.02.009.
Apel E, Deubener J, Bernard A, Höland M, Müller R, Kappert H, et al. Phenomena and mechanisms of crack propagation in glass-ceramics. J Mech Behav Biomed Mater 2008;1:313–25. doi:10.1016/j.jmbbm.2007.11.005.
Apel E, Hoen C Van, Rheinberger V. Studies of crystal phase formations in high-strength lithium disilicate glass – ceramics 2006;c:4041–50. doi:10.1016/j.jnoncrysol.2006.06.039.
Dittmer M, Ritzberger C, Schweiger M, Rheinberger V, Wörle M, Höland W. Phase and microstructure formation and their in fl uence on the strength of two types of glass-ceramics. J Non Cryst Solids 2013:1–6. doi:10.1016/j.jnoncrysol.2013.03.009.
Wange P, Höche T, Rüssel C, Dieter Schnapp J. Microstructure-property relationship in high-strength MgO–Al2O3–SiO2–TiO2 glass-ceramics. J Non Cryst Solids 2002;298:137–45. doi:https://doi.org/10.1016/S0022-3093(02)00950-X.
Tulyaganov DU, Ribeiro MJ, Labrincha JA. Development of glass-ceramics by sintering and crystallization of fine powders of calcium-magnesium-aluminosilicate glass. Ceram Int 2002;28:515–20. doi:10.1016/S0272-8842(02)00004-4.
Goharian P, Nemati A, Shabanian M, Afshar A. Properties, crystallization mechanism and microstructure of lithium disilicate glass-ceramic. J Non Cryst Solids 2010;356:208–14. doi:10.1016/j.jnoncrysol.2009.11.015.
Dittmer M, Müller M, Rüssel C. Self-organized nanocrystallinity in MgO – Al 2 O 3 – SiO 2 glasses with ZrO 2 as nucleating agent 2010;124:1083–8. doi:10.1016/j.matchemphys.2010.08.037.
Huang S, Cao P, Wang C, Huang Z, Gao W. Journal of Asian Ceramic Societies Fabrication of a high-strength lithium disilicate glass-ceramic in a complex glass system. Integr Med Res 2013;1:46–52. doi:10.1016/j.jascer.2013.02.007.
Zhao T, Qin Y, Wang B, Yang JF. Improved densification and properties of pressureless-sintered lithium disilicate glass-ceramics. Mater Sci Eng A 2015;620:399–406. doi:10.1016/j.msea.2014.10.037.
Jacquin JR, Tomozawa M. Crystallization of lithium metasilicate from lithium disilicate glass. J Non Cryst Solids 1995;190:233–7. doi:10.1016/0022-3093(95)00231-6.
Iqbal Y, Lee WE, Holland D, James PF. Metastable phase formation in the early stage crystallisation of lithium disilicate glass. J Non Cryst Solids 1998;224:1–16. doi:10.1016/S0022-3093(97)00453-5.
Stookey SD. Catalyzed Crystallization of Glass in Theory and Practice. Ind Eng Chem 1959;51:805–8. doi:10.1021/ie50595a022.
Zanotto ED. Metastable phases in lithium disilicate glasses. J Non Cryst Solids 1997;219:42–8. doi:https://doi.org/10.1016/S0022-3093(97)00249-4.
Yuan K, Wang F, Gao J, Sun X, Deng Z, Wang H, et al. Effect of sintering time on the microstructure, flexural strength and translucency of lithium disilicate glass-ceramics. J Non Cryst Solids 2013;362:7–13. doi:10.1016/j.jnoncrysol.2012.11.010.
Gaddam A, Fernandes HR, Ferreira JMF. Glass structure and crystallization of Al and B containing glasses belonging to the Li2O-SiO2 system. RSC Adv 2015;5:41066–78. doi:10.1039/c5ra04184h.
Von Clausbruch SC, Schweiger M, Höland W, Rheinberger V. The effect of P2O5 on the crystallization and microstructure of glass-ceramics in the SiC2-Li2O-K2O-ZnO-P2O5 system. J Non Cryst Solids 2000;263–264:388–94. doi:10.1016/S0022-3093(99)00647-X.
Cormier L. Nucleation in glasses – new experimental findings and recent theories. Procedia Mater Sci 2014;7:60–71. doi:10.1016/j.mspro.2014.10.009.
Rüssel C, Keding R. A new explanation for the induction period observed during nucleation of lithium disilicate glass. J Non Cryst Solids 2003;328:174–82. doi:10.1016/S0022-3093(03)00468-X.
Höland W, Rheinberger VM, Ritzberger C, Apel E. Surface or internal nucleation and crystallization of glass-ceramics. Opt Mater (Amst) 2013;35:1756–8. doi:10.1016/j.optmat.2013.04.023.
Khalkhali Z, Yekta BE, Marghussian VK. Preparation of lithium disilicate glass-ceramics as dental bridge material. J Ceram Sci Technol 2014;5:39–44. doi:10.4416/JCST2013-00030.
Fernandes HR, Tulyaganov DU, Goel IK, Ferreira JMF. Crystallization process and some properties of Li2O-SiO 2 glass-ceramics doped with Al2O3 and K 2O. J Am Ceram Soc 2008;91:3698–703. doi:10.1111/j.1551-2916.2008.02724.x.
Wang F, Li K, Ning C. Sintering properties of sol–gel derived lithium disilicate glass ceramics. J Sol-Gel Sci Technol 2018;87:372–9. doi:10.1007/s10971-018-4738-3.
