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44XV International Symposium on Self-Propagating High-Temperature Synthesis
REACTIVE FLASH SPARK PLASMA SINTERING OF ALUMINA REINFORCED BY SILICON CARBIDE NANOCOMPOSITES: PHYSICOCHEMICAL STUDY
M. Abedi*", D. O. Moskovskikh", and A. S. Mukasyan*
aNational University of Science and Technology MISiS, Moscow, 119049 Russia ^Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, 46556 USA *e-mail: abedi@edu.misis.ru
DOI: 10.24411/9999-0014A-2019-10004
Possessing numerous excellent properties such as high hardness, excellent oxidation resistance, remarkable chemical stability, noticeable wear resistance and great thermal shock resistance of alumina-based composites have attracted the attention of researchers since the last few decades. However, due to the fact that the mechanical properties of strength and fracture toughness of AhO3 are relatively low, application of these types of ceramics is subject to limitations [1]. In order to overcome this obstacle, strengthening and toughening of ceramics by the dispersion of the second phase as a reinforcement of ceramic matrix has been utilized.
It has been demonstrated in the previous studies that the addition of SiC as a reinforcement particle in the alumina matrix increases the strength, wear and creep resistance, as well as fracture toughness of the ceramic. The addition of SiC particles to alumina-based composites led to a change in fracture mechanism from intergranular to transgranular [2].
Previously, the AhO3/SiC composites have been fabricated by hot pressing, as well as spark plasma sintering (SPS). Recently, a novel method of sintering has been developed which is known as flash sintering which is capable of the fully densifying different type of material less than one minute [3]. This method is based on applying a very high electrical power to the sample which extremely accelerated the consolidation process of the materials. Although this method initially was developed for materials with negative temperature coefficient for electrical resistivity, it has been shown that this technique has the ability to sinter materials with all range of electrical conductivity including metallic conductors, ionic conductors, semiconductors and room temperature insulators. Furthermore, other methods of flash sintering were developed by inspiring of the basic model. One of these techniques is flash spark plasma sintering (FSPS), which works by a modification of tooling setups of conventional SPS [4].
In this work, we applied a novel consolidation method, so-called, reactive flash spark plasma sintering (RFSPS). RFSPS comprises the application of FSPS conditions to the AhO3-Si/C powder mixture, which contains reactive nanostructured Si/C particles prepared by high-energy ball milling technique. The SiC phase content varies in the range 0-20 wt % and AhO3 powder with particles of less than 60 nm is used. Alumina reinforced by SiC nanocomposites are produced by SPS, FSPS, and RFSPS techniques and their properties are compared. Specifically, the dependence of final materials' density versus carbide amount is explored. Furthermore, the mechanical properties of obtained ceramics including the fracture toughness and Vickers hardness are measured and analyzed. It is found that the hardness and fracture toughness of obtained nanocomposites grow by increasing reinforcement content.
iSHS 2019 Moscow, Russia
The authors gratefully acknowledge the financial support of the Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of MISiS (Support project for young research engineers)
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2. S. Gustafsson, et al., Pressureless sintered AhO3-SiC nanocomposites, Ceram. Int., 2008, vol. 34, no. 7, pp. 1609-1615.
3. M. Cologna, B. Rashkova, R. Raj, Flash sintering of nanograin zirconia in < 5 s at 850°C, J. Am. Ceram. Soc., 2010, vol. 93, no. 11, pp. 3556-3559.
4. C. Manière, G. Lee, E.A. Olevsky, All-materials-inclusive flash spark plasma sintering, Sci. Rep., 2017, vol. 7, no. 1, 15071.
