RosalÃa Poyato
CSIC-Universidad de Sevilla, Spain
Title: Effect of the homogenization treatment on the microstructure and the electrical conductivity of 3YTZP/graphene nanoplatelet composites
Biography
Biography: RosalÃa Poyato
Abstract
Nowadays, graphene nanoplatelets (GNPs) are being considered as an emerging class of nanomaterials. GNPs are composed of ten or more graphene layers, with thickness up to 100 nm, and present unusual mechanical and electrical properties1,2. These characteristics have motivated a great interest in incorporating these nanostructures as second phase in a ceramic matrix, in order to enhance the mechanical and functional properties of the final composite3-5. However, one of the main obstacles to be overcome is obtaining a good dispersion of the GNPs into the ceramic matrix.
In this work, 3YTZP based composites with different GNP contents were prepared using different powder homogenization methods and electric pulsed discharge sintering (also called spark Plasma Sintering or SPS). Composite powders were prepared by tip-sonication in isopropanol and/or by planetary ball milling under dry or wet conditions. The effect of milling and ultrasonic agitation on GNP integrity and particle size has been evaluated by Raman spectroscopy and laser granulometry. Microstructure of the composites has been analysed by electron microscopy, X-ray diffraction and Raman spectroscopy to assess the integrity of the GNPs, their degree of dispersion or agglomeration in the ceramic matrix and the stabilization of the tetragonal phase in the 3YTZP matrix. The relationships between GNP content and dimensions, microstructure and electrical conductivity, as well as the conduction mechanisms of the composites, have been analysed and discussed.