Y3Al5O12-α-Al2O3 composites with fine-grained microstructure by hot pressing of Al2O3-Y2O3 glass microspheres. Issue 3 (March 2020)

• Record Type: Journal Article
• Authors: Prnová, Anna; Valúchová, Jana; Parchovianský, Milan; Wisniewski, Wolfgang; Švančárek, Peter; Klement, Robert; Hric, Ľubomír; Bruneel, Els; Galusek, Dušan
• Is Part Of: Journal of the European Ceramic Society. Volume 40:Issue 3(2020)
• Page Start: 852
• Page End: 860
• Publication Date: 2020-03
• Subjects: Yttrium-Aluminate glass -- Eutectic structure -- Hot-Press sintering -- Vickers hardness -- Fracture toughness; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2019.10.017
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Yttrium aluminate glass microspheres with the eutectic composition 76.8 mol. % Al2 O3 and 23.2 mol. % Y2 O3 were prepared by combining the sol-gel Pechini method with flame synthesis. The sol-gel method was applied to achieve the desired composition homogeneity of the prepared glass and hence, improve the microstructure homogeneity and mechanical properties of bulk polycrystalline materials. The latter were prepared by hot pressing, more specifically pressure assisted sintering, at 1050 °C, 1300 °C and 1600 °C using pressures of 30 MPa and 80 MPa and holding times between 0 and 30 min. This also led to the crystallization of the glass. A composite with the Vickers hardness 18.0 ± 0.7 GPa and an indentation fracture toughness 4.9 ± 0.3 MPa.m 1/2 was obtained by sintering at 1600 °C, at the pressure of 80 MPa and with 30 min isothermal heating at the maximum temperature. Improved mechanical properties were observed when increasing the temperature of sintering and the holding time. This can be attributed to the formation of a unique microstructure consisting of α-Al2 O3 grains in the μm-scale embedded in a YAG (yttrium-aluminium garnet) matrix in the hot-pressed samples.