PhD in Understanding the interaction of galling and oxidation in hard facing materials.

Hard facing materials are widely used in valves for industrial applications where wear and galling resistance is a key requirement. StelliteTM materials are used for these purposes thanks to their superior performance related to their cobalt-base matrix which is strengthened with tungsten and chromium carbides. However, for nuclear base applications, wear and corrosion products from these alloy systems can form radioactive Co-60 that provides a major source of out-of-core radiation.

To reduce occupational exposure of workers during inspection and maintenance of nuclear power plants, new Co-free hard facing materials are sought after. Currently, new galling resistant Co-free materials are being developed based on stainless steels matrices, which include various fractions of carbides and nitrides. While their galling performance can be easily explored in dry environments there is currently no experimental set-up that enables galling testing new Fe-based alloy developments in more realistic environments, i.e. at 300°C in pressurised water. For this reason a new rig has been designed and built within the Royce Institute at the University of Manchester to mimic in full the contact conditions experienced by sliding surfaces of valves in simulated nuclear environment. This first of a kind rig will be employed to provide fundamental data required for the development of new materials.
The project will be carried out within the Materials Performance Centre at the University of Manchester and the Royce Institute which have extensive expertise in microstructural characterization, metallurgy, oxidation, and structural integrity of nuclear components and provide access to state-of-the-art material characterization and experimental facilities. The successful candidate will acquire skills in materials performance, developing experimental protocols for galling testing in pressurised water environments and will become proficient in the materials and microstructural characterization, which include secondary electron microscopy (SEM), focused ion beam (FIB), transmission electron microscopy (TEM), X-ray diffraction (XRD) and other advanced characterization techniques. The project will also benefit from the professional guidance and the significant expertize of Rolls-Royce.

The aim of this project is to develop the mechanistic understanding of galling of newly developed hard facing materials in simulated nuclear environment and understand the environmental effects, loading conditions and temperature on the galling wear resistance. The scientifically-based understanding of the various underlying mechanisms influencing/controlling the oxidation and deformation can then be used as a feedback for the optimization of new materials.

For more information please contact Dr Fabio Scenini ([Email Address Removed]).