Effect of crystal size on the tribological properties of lithium disilicate glass-ceramics sliding against alumina and tungsten carbide spheres
Industrial Lubrication and Tribology
ISSN: 0036-8792
Article publication date: 22 May 2020
Issue publication date: 9 November 2020
Abstract
Purpose
Lithium disilicate glass-ceramics (LS2 GC) are widely used as dental prosthetics and dental restorations. Based LS2 GC have hardness and translucency similar to that of natural teeth. This study aims to investigate the tribological features of LS2 GC with crystalline volume fraction of 64% and different crystal sizes from 8 µm to 34 µm for different counterparts.
Design/methodology/approach
The tribological behavior was investigated using a pin-on-disc tribometer with alumina and tungsten carbide (WC) spheres, applied load of 5 N and sliding speed of 5 cm/s at normal conditions. The coefficient of friction was measured continuously up to 10,000 sliding cycles. The specific wear rate was calculated from tribological and profile measurements. The wear mechanism was investigated by surface morphology analysis.
Findings
The coefficient of friction during running-in varied from 0.8 to 1.0 for the alumina counterpart, because of severe wear. Afterwards, it reduced and reached a stationary regime, characterized by a mild wear regime and the formation of a tribolayer formed by the debris. For the WC counterpart, the coefficient of friction curves increased initially with sliding cycles up to a stationary regime. The samples tested against WC presented the lowest specific wear rate (k), and no variation of wear rate with crystal size was observed. For samples tested against the alumina, crystallization and crystal size increased the wear resistance.
Originality/value
This study evaluated the effect of different counterfaces on the tribological properties of the LS2 GC, an important glass-ceramic base for many dental prosthetics and dental restorations, discussing results in light of the contact mechanics. Different specific wear rates, wear regimes and dependence on the glass-ceramic microstructure were observed depending on the counterpart.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2019-0352/
Keywords
Acknowledgements
The authors are grateful for the financial support of CAPES/Brazil and UGF/PR, C-LABMU/UEPG/Brazil for the use of the research facilities and the Vitreous Material Laboratory (LaMaV)/UFSCar/Brazil for melting the glass.
Citation
da Cruz, C., Mathias, I., Senk, M.V., Biscaia de Souza, G. and Serbena, F.C. (2020), "Effect of crystal size on the tribological properties of lithium disilicate glass-ceramics sliding against alumina and tungsten carbide spheres", Industrial Lubrication and Tribology, Vol. 72 No. 9, pp. 1109-1116. https://doi.org/10.1108/ILT-08-2019-0352
Publisher
:Emerald Publishing Limited
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