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Structural and Functional Ceramics
A broad definition of ceramics covers all inorganic nonmetallic materials. Advanced ceramics have found far wider applications in modern society than traditional porcelain and potteries, ranging from high speed cutting tools, thermal insulating blankets for space shuttles to components in mobile phones and medical ultrasonography. Research activities in the Department of Materials Engineering include developments of advanced ceramic materials for both structural and functional applications. A major interest has been in the field of engineering ceramics for applications requiring high strength, abrasion resistance, thermal shock resistance, chemical durability and refractoriness. Research projects have been carried out in processing and characterisation of advanced structural ceramics, including silicon nitride, sialons, silicon carbide, boron carbide, titanium boride and their composites. Through controlled processing, Ca alpha-sialon ceramics with elongated grain morphology were first developed by the team at Monash. The materials have enhanced fracture toughness combining with their intrinsic high hardness. Collaboration with researchers in Shanghai Institute of Ceramics, Chinese Academy of Sciences has led to the development of a novel SHS (self-propagating high-temperature synthesis) technique for producing advanced alpha-sialon ceramics using blast furnace slag as a starting material. Ceramic wear parts made of the slag derived sialon have showed excellent anti erosion and wear performance in on-site tests.
 Ceramic bearing balls made from the slag derived alpha-sialon.
Ceramic-polymer composites have shown many interesting properties. The Ceramic Group is involved in the development of novel ceramifiable polymer-ceramic composites for fire-performance cables, supported by the Polymer CRC. Unlike conventional polymers that typically breakdown in a fire emergency, the ceramifiable polymer transforms into a protective ceramic barrier, providing continuous insulation for the cables to work in a fire situation and thus saving lives. Mixtures of ceramic fillers were tailored and incorporated into polymer matrices, allowing the formation of coherent, strong and dimensionally stable ceramic residuals after polymer pyrolysis. The materials were successfully applied in the manufacturing of the world’s first ceramifiable cables by an Australian company, Olex Cables, in 2003. Research is continuing with the renewed CRC-Polymers to apply ceramifiable polymers for broader passive fire protection applications.
 Fire performance ceramifiable cables before (left) and after (right) firing at 1050°C.
Development of renewable energy has been a major driving force for research in recent years. Among many alternatives, solar energy stands as one of the most attractive renewable energy sources. Dye sensitized solar cell (DSSC) employs advanced nanotechnology and represents the most promising low-cost alternative to silicon solar cells at the present time. A major component of DSSC consists of a nanoporous ceramic (TiO2) film as a semiconductor electrode. The interest of the Ceramic Group is to develop the nanoporous semiconductor films with controlled microstructure and chemistry to improve solar energy to electricity conversion efficiency. Projects supported by the ARC, the Australian Centre of Excellence in Electromaterials Science and Victorian Government are working on the development of various dye sensitized solar cells, including monolithic devices, tandem devices, solid state devices and flexible solar cells using polymer as substrates.
Solid Oxide Fuel Cell (SOFC) materials are another departmental ceramics initiative undertaken in the energy conversion field. Cubic zirconia is at present the main candidate
electrolyte material for the new generation of high-temperature large-format fuel cells, whose installed capacities range from the power requirements of a single house to those of a small town. These devices, providing a highly efficient “flameless burn” of a wide variety of fuels, operate by the conduction of oxygen ions through the solid zirconia electrolyte, rather than by the conduction of electrons. Compared with electrons, however, the mechanism of ionic conduction through oxide ceramics is poorly understood, and delays the development of more efficient and flexible fuel cells. Two aspects comprise the research undertaken into zirconia ceramics at Monash University. The first has involved structural studies of the ceramics, chiefly using electron microscopy and diffraction: the second aspect is an attempt to connect the structure of the ceramics with their ionic conduction performance. More recently, this has included the deployment of probe techniques such as Nuclear Magnetic Resonance (NMR), Electron Spin Resonance (ESR) and Positron Annihilation Lifetime Spectroscopy (PALS).
Active researchers in this field:
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