2021 FutureNow Plus Scholarship - Ultra-High Temperature Ceramics PhD position null

Background

Ultra-High Temperature Ceramics (UHTCs) is a subclass of emerging high-temperature materials for extreme environments – e.g. combination of temperature, radiation, and corrosion. Chemically, most UHTCs are binary compounds of B, C, or N with one of the transition metals: Hf, Ta, Nb, Zr, Ti, V, etc. The high strength and melting temperature (> 2500°C) of these compounds stem from the covalent bonds, while enhanced thermal and electrical conductivity stem from their metallic character. In general, these metal-ceramic bonds between the constituent atoms give UHTCs a combination of metal-like and ceramic-like thermo-physical-mechanical properties leading to their excellent high-temperature performance. Such a unique combination of thermo-physical-mechanical properties makes UTHCs suitable as an engineering material for a broad range of applications across energy, space and defence sectors. However, the thermo-physical properties (e.g. high melting point, strong covalent bonding and low intrinsic self-diffusivity) which make these ceramics excellent in high-temperature applications make their processing and densification extremely difficult, requiring high temperatures and pressures.

Project Information

This project will focus on the development, and assessment of single and multiphase UHTCs (e.g. HfB2, ZrB2, HfC) as these materials have application in the next generation fission/fusion energy-generating systems, space and defence applications. The proposed PhD project will first aim to address a number of high-level challenges associated with fabrication of UHTCs such as the effect of various second-phase additives/aids (SiC, C, B4C, MoSi2, etc.) and processing routes (e.g. vacuum hot pressing/sintering, cold-pressing followed by pressureless sintering, hot isostatic pressing) on the densification, grain growth, and high-temperature strength.

Prepared UHTCs will be systematically characterized using various diffraction and microscopy techniques readily available at ANSTO to investigate the additives-processing-structure relationship. This will allow for a rapid modification and optimization of additives/processing with the view of obtaining functional microstructural characteristics of engineered UHTCs. Compounds that meet microstructural and density requirements will be subjected to further high-temperature testing taking advantage of various high-temperature facilities available at ANSTO and DSTG (Defence Science and Technology Group). For example, we will investigate the kinetics of the oxide layer formation on the surface of prepared UHTCs during an exposure to extreme temperatures in oxidising environments. The oxidation behaviour will be studied with respect to the composition, processing routes and microstructure to evaluate characteristics governing formation of protective oxide layer. In the final stage of the proposed project we will explore the scalability (upscaling) of the developed processing routes and near-net shape part production for industrial applications.

Funding And Support

This project is jointly supported by DSTG and ANSTO via FutureNow Plus scholarship.

The successful PhD candidate is expected to work collaboratively across both institutions as well as a host university.

The student will receive a full FutureNow PhD scholarship of $35k/year, or a combination of $15k/year top-up and the Australian Government Research Training Program (RTP) stipend scholarship.

Additional funding of $10k/year from ANSTO's FutureNow Plus is available for travel and consumables of the project.

Application Details

A background in materials science, chemistry, physics or engineering is welcome.
We value diversity and encourage applicants from all backgrounds to apply, however, this program is open to Australian citizens only.