Studentships and scholarships in corrosion and protection
Corrosion and Protection
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For further information about PhD studentships and scholarships in the School of Materials, please contact our Postgraduate Team.
- PhD Corrosion and Protection
Effect of Steel Metallurgy on Corrosion Scale Formation in Oilfield Environment
This Ph.D. project aims to provide a better understanding of the formation of corrosion scales on heat-treated mild steel in H2S/CO2 containing oilfield environments. Test will be carried out using the new autoclave facilities at the Corrosion & Protection Centre, with a focus on probing the effect of substrate metallurgy, environmental parameters (temperature & pressure), and changes in water chemistry. The research will primarily focus on the application of novel characterisation techniques to analyse the physical and chemical nature of surface scales developed during oilfield extraction and exploration. Electrochemical measurements will be carried out, supported by high-resolution electron microscopy, crystallographic and compositional analysis, scale porosity/permeability measurements and x-ray computed tomography. The composition of thin scales will also be probed using angle resolved x-ray photoelectron spectroscopy and glow discharge optical emission spectroscopy. A miniature autoclave system with a X-ray transparent window will be developed for in-situ characterisation of scale morphology and structure, using X-ray diffraction- and tomography-based techniques.
Supervisor: Dr Dirk Engelberg
Improvement of Wear and Corrosion Performance of Aluminium Metal Matrix Composites by Excimer Laser Surface Modification
Our initial work, in collaboration with Aerospace Metal Composites Ltd (AMC), UK, on excimer laser surface modification of AA2124-SiC composites has showed a significant improvement in corrosion performance due to dissolution of the reinforcing particles within the top layer of the materials (see Figure below). This project aims to investigate wear and corrosion performance of excimer laser-melted AA2124-SiC with SiC particle sizes from micro- to nano-scales. It will focus on the mechanisms involved in wear and corrosion behaviour of the composites with and without laser treatment.
Supervisor: Dr Zhu Liu
Corrosion control of friction welded dissimilar alloys
Friction welding of dissimilar alloys is of great interest in many industrial sectors, including Oil and gas, aerospace, automotive, railway and marine industries. During welding, the thermally affected zone (HAZ) and thermo-mechanically affected zone (TMAZ) are developed. In this study, the influence of the microstructure within the TMAZ and TAZ on corrosion resistance will be assessed using electron microscopy and accelerated testing. Surface protective means will be developed for the generation of corrosion resistant surfaces on the weld through further modification of the microstructure.
Supervisor: Dr Xiaorong Zhou
Oxidation and Hydriding of Zirconium Alloys in High Temperature Water Environments
The aim of this project is to assist in the development of a fully mechanistic understanding of the aqueous corrosion of zirconium alloys. Currently, corrosion of Zr-alloys (both oxidation and hydriding) limits the performance of the alloys in heat exchanger systems and in high temperature water (with applications in the chemical, process and nuclear industries). The student will join a multi-disciplinary team in Manchester with collaborators from other Universities and commercial organisations. The project will focus largely on hydriding of zirconium, which is a key degradation process that is currently rather poorly understood. The research will comprise generic, fundamental science and will use electrochemical and electron-optical techniques in the investigation. A particular aim of the project will be the early detection of hydriding and hydrogen permeation via electrochemical approaches.
Supervisor: Professor Stuart Lyon
Tomography for Understanding Materials Degradation
Localized corrosion can provide potential sites for subsequent cracking, leading to potential catastrophic consequences and, therefore, has attracted intense attention over the last decades. However, many questions remain unanswered about the local microstructural criteria for the initiation and development of localized corrosion. To a degree, this is because microstructural information previously obtained by conventional two-dimensional (2D) characterization techniques is often inadequate for providing an accurate reflection of the true three-dimensional (3D) microstructure and associated localized corrosion. In the present study, methods will be developed to enable in-situ and ex-situ nanotomography of localized corrosion, therefore, to advance understanding of the mechanism of material degradation.
Supervisor: Dr Xiaorong Zhou
Environmentally-Friendly Novel Coatings for Aerospace Alloys
In aerospace industry, significant efforts are being made to develop environmentally-friendly coatings to replace conventional coatings such as cadmium coatings. Cadmium has been used for many years in aerospace owing to its excellent corrosion resistance and engineering properties. However, because of the toxicity of cadmium and its salts, environmentally-friendly, alternative coatings with equivalent or improved performance are urgently needed. The project is aimed at developing environmentally-friendly, novel coatings for aerospace alloys.
Supervisor: Dr Xiaorong Zhou
Influence of Machining on Performance of Aluminium Alloys for Transport
Machining of the surfaces of light alloys is undertaken to provide the required shape and to repair damage. However, the associated high surface shear processes combine to generate nanograined, near-surface structures that, depending on material processing conditions, can be active and contribute to premature failure due to the rapid onset of corrosion. In this study, the formation of such layers through machining of selected alloys in various tempers will be examined to determine the influence of prior structure on surface reactivity. Having fored such layers means to eradicate their formation in thermomechanical processing will be determined as well as surface pretreatments involving etching and pickling. The study will be progressed using electronoptical approaches to explain the electrochemical behaviour of the mechanically treated alloys and the resultant performance in corrosion tests.
Supervisor: Professor George Thompson
Conversion Coating of Aluminium Alloys
New and effective conversion coating treatments to replace the ubiquitous chromate coatings are eagerly awaited for light alloys that extensively employed in the transport sector. Here, an inorganic/organic sol gel coating with incorporated nanoparticles of rare earth oxide compounds will be examined to determine adhesion over the macroscopic alloy surface, barrier corrosion properties and self healing ability. By control of nanoparticle, type, volume fraction and location, the aim is to impact on the barrier protection properties of the coating, with consideration of its location being used to support the self-healing properties. The study will be undertaken using electrochemical and surface analysis approaches, supported by detailed electronoptical examination of the coatings and interfaces within the coating.
Supervisor: Professor George Thompson
Controlled Anodic Oxide Growth for Pretreatment of Aluminium Alloys
Anodizing of aluminium is widely used to provide corrosion and wear resistant coatings for application in architecture, lithography, packaging and transport. Using a knowledge-based approach, this study aims to prepare the alloy surface for reduced corrosion susceptibility by preferred removal of second phase material that is intimately associated with the corrosion process and limited interfacial enrichment of alloying elements that can contribute to alternative anodic processes during protective film formation,. Further, by control of the conditions, rte macroscopic filming behaviour of the alloy surface will also be examined to determine its functionality for specific applications. The study will be progressed using advanced electrochemical approaches, i.e. anodizing spectroscopy, supported by ion beam analyses and electron microscopies.
Supervisors: Prof Professor George Thompson/Prof Professor Peter Skeldon
Design and evaluation of passive films for large area electrodes used in instrumentation for mass spectrometers
Electrospray ionization source of a mass spectrometer
Mass spectrometers (MS) are used in a wide range of industries, typically pharmaceutical, proteomics, clinical, food safety, environmental etc. MS instruments are a key enabling technology in metabolite profiling and identification, in mapping the human proteome, in post natal screening, in monitoring therapeutic drug levels, in testing for performance enhancing drugs in world class athletes, in monitoring the quality of international and national food supplies, and in monitoring environmental change. The ever increasing demands from these highly focused disciplines, for improved acquisition rate, sensitivity, selectivity, specificity, etc. is driving the technological development and innovative design of MS instruments.The design approach applied for the instrumentation within mass spectrometers incorporates the use of large area electrodes to define the bounds of the E-fields that are employed in the generation, transport, analysis and detection of ions and their structural derivatives. These electrodes are made from either a non-conducting or conducting materials. The central interest of this study is the development of surface management techniques to optimize the functionality of the surfaces of the electrically conducting large area electrodes. Austenitic stainless steels are typically used for large area electrically conducting electrodes in MS instrumentation. The passive films formed on these materials have been extensively studied in terms of their ability to provide corrosion protection in applications seen in the chemical, petrochemical, electronics and transportation industries but their impact on the electronic functionality of large area electrodes used in analytical instrumentation is less well documented. Inhomogenity in the electronic characteristics of the surfaces of the electrodes, that define the bounds of prescribed E-fields, can result in the generation of perturbations and asymmetry in such E-fields and this may, potentially, result in the imperfect functioning of an associated piece of MS instrumentation. It is well known that the oxides formed on stainless steel tend to have semi-conducting characteristics of an imprecise nature. Clearly, it is important, for the development of appropriate surface management techniques, that the oxide film be extensively characterized in terms of band gap energy, doping concentration, dielectric constant, and semiconducting character and this be rationalized in terms of their overall effect on the functioning of stainless steel electrodes used in MS instrumentation. This work will examine the effect of different compositions and structures of oxides, grown on stainless steel substrates under anodic and cathodic conditions, on these governing properties. The films will be characterized in detail with respect to their composition, morphology and structure. Work will evaluate the response of such films to different electrostatic and electromagnetic E-field driving forces and to electron and ion beam irradiation. The work will conclude with the development of electrochemical methods for the generation and control of specific oxide compositions and structures that optimize the functionality of large area austenitic stainless steel electrodes used in MS instrumentation. This research and development activity will provide significant technological advancements in the surface engineering of components that make up critical features in MS instrumentation and so participate in meeting the scientific demands being imposed on MS instrument design and development.
Supervisor: Professor Peter Skeldon
- PhD Corrosion and Protection/ LATEST2
PEO Coatings for Multi-Materials
New designs of cars and other transport vehicles are increasingly utilizing a range of materials in order to improve the energy-efficiency and overall performance. The mixing of different forms of alloys (e.g. cast and wrought), of different grades of alloy (e.g. various types of aluminium alloy) and of different types of alloy (e.g aluminium alloys with steel or magnesium alloys) introduces stringent requirements on surface treatment processes, which are essential for corrosion protection. Surface treatments must be tolerant of the differing compositions and microstructures of the materials, while providing the necessary degree of durability of the treated parts. Plasma electrolytic oxidation is a process that can be applied to all of the light alloys (aluminium, titanium and magnesium), and is being considered for application to steel. Hence, it is a potential candidate for surface treatment in multi-material systems. However, no investigations have been reported in the literature of its suitability under such circumstances or of the factors that determine its applicability. Thus, there is a requirement for fundamental studies of the conditions under which coatings can be formed on multimaterials using a single process (e.g. electrolyte composition, current density, waveform, duty cycle etc) and the parameters that control the growth of the coatings (e.g. types of microdischarges, composition of the substrates etc). The project will use the results of basic studies of the coating growth on a range of alloys (examining in detail the composition and microstructure of the coatings and optical emissions from microdischarges in order to understand the mechanism of growth) to underpin the development of electrolytes and processing conditions for a range multi-materials. The studies will encompass the light alloys, and also steels, the latter providing a greater challenge, but offering high potential rewards. Practical assistance and background expertise in PEO technology will be supplied by Keronite, a company which is developing PEO for commercial applications and which is seeking to expand the PEO market.
An example of a relatively thick PEO coating, showing a porous inner region and a more compact outer region.
Supervisor: Professor Peter Skeldon
- PhD Corrosion and Protection/ LATEST2
Enhanced performance coatings produced by plasma electrolytic oxidation
Plasma electrolytic oxidation (PEO) produces ceramic coatings on metals that provide the treated surfaces with a high hardness. The technology has been commercialized, and is particularly used with magnesium alloys. However, PEO can also treat aluminium and titanium alloys, and possibly also steel. Hence, it has a versatility that makes it potentially attractive for surface treatment of components manufactured from a mixture of materials. The coatings are usually formed in aqueous electrolytes, with the coating material forming at sites of microdischarges on the coated surface. The coating material may be formed by a combination of anodic, thermal and plasma processes, under local temperatures cycles that result in melting, rapid solidification and phase transformations in the coating layer. The resulting layers are porous and contain microcracks due to the mechanism of their formation, the degree of porosity being dependent on the conditions of PEO processing. A wider uptake of the technology requires that the performance of coated parts is improved, particularly in respect of corrosion protection.The project will seek to enhance coating performance through pre-treatments of the substrates, post-treatments of the coated alloys, and modifications of electrolyte formulations. Areas to be considered are effective sealing of porosity (e.g. using sol-gel) and creation of coatings with active corrosion protection, through incorporation of inhibitor species (e.g. rare earth species). The work will involve detailed analytical investigations of coatings on a range of alloys (using SEM, TEM, EPMA, XRD), allied with electrochemical studies of corrosion and inhibition mechanisms, and testing of coated parts. Understanding of the breakdown of corrosion protection will be sought through the development of in-situ x-ray tomographic imaging, with rapid screening of potential inhibiting and sealing methods achieved by split-cell electrochemical methods.
Solidification crystal structure at the surface of a PEO coating
Supervisor: Professor Peter Skeldon
- PhD Corrosion and Protection/ LATEST2
Protective oxides on stainless steel in hot acid environments
Stainless steels ether actively dissolve or immune in hot sulphuric, phosphoric and hydrochloric acids depending on electrochemical potential of the steel in the acid. Steel performance under anodic and cathodic polarisation is a subject of this study. Polarisation and additives to the acid solution lead to the changes in protective oxide film properties that can find numerous applications from the functionalisation of the steel surface (selective adsorption, improvement in corrosion resistance, water repellence and so on) to the decorative (coloured stainless steel). Surface analytical approaches will be utilised in this work.
Supervisor: Dr Elena Koroleva
- PhD Corrosion and Protection/ LATEST2
Study of calcareous deposition on the mild steel
Stainless steels ether actively dissolve or immune in hot sulphuric, phosphoric and hydrochloric acids depending on electrochemical potential of the steel in the acid. Steel performance under anodic and cathodic polarisation is a subject of this study. Polarisation and additives to the acid solution lead to the changes in protective oxide film properties that can find numerous applications from the functionalisation of the steel surface (selective adsorption, improvement in corrosion resistance, water repellence and so on) to the decorative (coloured stainless steel). Surface analytical approaches will be utilised in this work.
Supervisor: Dr Elena Koroleva
- PhD Corrosion and Protection/ LATEST2
Lithography and lotus leaf effect
Scanning Electron micrograph of electrograined aluminium in HCl acid solution reveals the surface convolution through controlled pitting.
Electrograining is a stage of litho-plate production at the commercial plants of AGFA, Kodak and Fuji. Electrograining results in the aluminium surface convolution in hydrochloric and nitric acids and supports development of hydrophilic and hydrophobic areas on the offset lithographic plate during printing. Rough surface topography is an essential part of development of super-hydrophobic surface and developed through localised dissolution of the aluminium - pitting. The study is focused on the effect of alloy microstructure on metal surface chemistry/electrochemistry during pit development. The approaches used in the research will rely on the physical metallurgy of cold rolled aluminium, with emphasis on the roles of impurity segregation, grain and sub-grain boundaries and so-called mosaic structures, in controlling the observed electrochemical behaviour. Surface analytical approaches will be utilised in this work.
Supervisor: Dr Elena Koroleva
Response of the 6XXX series aluminium alloy extrusion profiles to surface treatments
The effect of microstructure evolved during extrusion and ageing of the 6XXX series aluminium alloys on alloy behaviour in surface treatments such as alkaline etching and anodising is a subject on the study. The extrusion profiles are intensively used in building and construction and their surface appearance after treatment should meet specified requirements. The study will focus on modification of composition and conditions of the etching and anodising baths that result in inhibition or promotion of electrochemical activity on the alloy surface. Electron and optical microscopic examination of the treated alloys combined with reflectance and gloss measurements and white light interferometry will be employed to assess surface modifications.
Supervisor: Dr Elena Koroleva
Material Degradation in Deep Geological Repository Environment
A deep geological repository for the storage and disposal of nuclear waste is proposed to be operational in the UK by 2040. Radioactive waste is likely to be immobilised and stored in steel canisters, and it is therefore important to understand the long-term behaviour of the canister materials under deep geological repository conditions. Potential disposal options for high-level and intermediate-level radioactive waste are based on the use of either bentonite mineral clays or cement as a backfill material to seal the repository. These materials are chosen to limit the release of radio-nuclides, to maintain the integrity of the waste container, and to stabilize the host-rock near field environment after repository closure. This Ph.D. project aims to characterise, in-situ, the long-term performance of steel in clay and weathered cement relevant to geological disposal of nuclear waste. High-resolution x-ray-computed tomography will be used to characterise, in-situ, the behaviour of steel in cement/clay-containing near field environments over extend exposure periods. Advanced image analysis/correlation methods, electron microscopy and elemental-mapping will also be used to quantify the presence and distribution of individual system constituents. Novel in-situ environmental cells will be coupled with electrochemical methods, to investigate the effect of contamination and deformation/swelling in bentonite and cement on steel corrosion. The objective of this work is to inform material prediction models about the long-term behaviour of steel, and the effect of steel corrosion on the near field, in a waste repository system after backfilling.
Supervisor: Dr Dirk Engelberg
Advanced Microstructure Engineering for Duplex Stainless Steels
Duplex stainless steels are used for critical application in oil & gas environment, nuclear plant, and as container material for the storage of radioactive waste. The microstructure consists of a balanced fraction of ferrite and austenite, which can be tailored for individual application using thermal- or thermo-mechanical treatments. Microstructure engineering is therefore a viable option to increase the corrosion resistance through, for example, optimisation of the distribution and connectivity of the phase and grain boundaries in this alloy. This Ph.D. project aims to explore advanced microstructure engineering for application with duplex stainless steel. The objective is to fully characterise the 3-dimensonal connectivity of ferrite and austenite, with their grain- and phase-boundaries, to achieve improved resistance to localised corrosion and stress corrosion cracking. Metallographic characterisation techniques will be coupled with serial sectioning, Scanning Electron Microscopy (SEM), elemental mapping and Electron Backscatter Diffraction (EBSD) techniques to inform about the distribution and connectivity of microstructure constituents. Image analysis and correlation will be explored for advanced microstructure analysis. Thermal and thermo-mechanical process routes will be used to control microstructure characteristics, and for the precipitation of second phases (i.e. carbides), which will be used as markers to guide advanced 3D microstructure assessment. Ion etching and electro-chemical techniques will be used to selectively attack the microstructure, which provides information about the connectivity of boundary and phase clusters.
Supervisor: Dr Dirk Engelberg