Exploiting the properties of graphene to improve the mechanical and functional properties of ceramic-based materials

Alemzadeh, Joseph 2024. Exploiting the properties of graphene to improve the mechanical and functional properties of ceramic-based materials. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Since the isolation of graphene in 2004, it has received the attention of numerous research groups across the world. Being the subject of a Nobel Prize in Physics in 2009, its incorporation into high-performance composites has grown increasingly due to its attractive qualities. Ceramic materials have been a promising candidate for graphene integration because of their inherent brittleness and poor resistance to fracture. Taking inspiration from natural materials that exhibit intricate architectures, researchers have managed to exploit possibilities to arrange graphene throughout ceramic microstructures to create highly-ordered ceramic-graphene materials. However, this is not without its challenges during processing which include the dispersion of graphene-related materials and the scalability of production. This research investigated a novel processing route which utilises advanced fabrication techniques to create bulk ceramic-graphene composites. This began with freeze-casting 30 mm alumina scaffolds that exhibit directionally-aligned pores between 20 – 70 μm in diameter. Prior to infiltration with water-based suspensions of graphene oxide, selected alumina materials were pre-sintered at 900 °C in air to remove casting additives and provide some mechanical strength through particle coalescence. Once infiltrated, alumina-graphene oxide scaffolds undergo Spark Plasma Sintering at 1300 °C to rapidly consolidate the composite scaffolds into dense compacts, whilst simultaneously transforming graphene oxide into reduced graphene oxide. The resulting microstructure consists of highly-oriented reduced graphene oxide throughout alumina layers between 0.5 – 7 μm thickness. The composite material was found to be 80 % tougher, 20 % stronger, and electrically active when compared to monolithic alumina.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Engineering
Uncontrolled Keywords:	1). Composites 2). Ceramics 3). Graphene 4). Spark Plasma Sintering 5). Freeze-casting 6). Fracture toughness
Date of First Compliant Deposit:	20 May 2024
Last Modified:	20 May 2024 12:54
URI:	https://orca.cardiff.ac.uk/id/eprint/168994

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