Speaker
Description
The fabrication of advanced ceramic matrix composites (CMCs) with low dimensional phases such as carbon nanotubes or graphene is currently an open research topic because their potentiality as reinforcement phases for tougher ceramics. Despite several decades of research, some common experimental issues, such as the homogeneity of the dispersion, their location within the ceramic matrix, and the type of bonding between reinforcing phase and the matrix, still hinder the achievement of unquestionable and significant mechanical reinforcements.
This work introduces a new fabrication procedure of fully-dense alumina matrix with graphene oxide flakes based on the sol-gel route and the reactive spark plasma sintering [1,2], as an alternative methodology to improve the dispersion of the graphene flakes within the composite, to induce the intragranular location of the flakes, and to promote the formation of strong bonds between graphene flakes and ceramic matrix such as Al-O-C oxygen bridges [3]. The micro- and nanostructure of these composites are researched by techniques such as nitrogen physisorption, Raman spectroscopy, electron microscopy and XPS. The high specific surface of the sol-gel precursor powder has revealed as an interesting characteristic for enhancing faster sintering. Thorough SEM inspections of the precursor powder have revealed the absence of graphene agglomerations. Raman analyses have confirmed the integrity of the graphene along the fabrication process. Besides, the mechanical properties are studied by Vickers indentations and uniaxial compression. Features such as hardness, Young’s modulus and indentation fracture toughness are measured for different graphene contents. Finally, results are compared with those from conventional alumina-graphene CMCs.
[1] P. Rivero-Antúnez et al., Ceram Int 46 (2020) 19723–19730
[2] M. Satam et al., J Amer Ceram Soc 99 (2016) 2905-2908
[3] I. Ahmad et al. J Compos Mater 52 (2018) 417–28
| Speaker Country | Spain |
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