Margaret Stack

University of Strathclyde · Department of Mechanical and Aerospace Engineering

Hail impact-induced erosion has the potential to significantly affect the operational lifetime of structures exposed to extreme weathering environments such as hail events. Computational materials modelling can be used to better understand the erosion behaviour during a hailstone impact, and here the relevant background work is detailed. In this pa...

Leading edge erosion is becoming increasingly important as wind turbine size and rainfall are predicted to increase. Understanding environmental conditions is key for laboratory testing, maintenance schedules and lifetime estimations to be improved, which in turn could reduce costs. This paper uses weather data in conjunction with a rain texture mo...

Within renewable energy, challenging climates can impose great limitations on power generation. In wind energy, rain erosion on turbine blades can create major disruptions to air flow over the aerofoil, reducing the efficiency of the blade and immediately affecting the power output of the turbine. The defects in the materials that cause these ineff...

Erosion rates of wind turbine blades are not constant, and they depend on many external factors including meteorological differences relating to global weather patterns. In order to track the degradation of the turbine blades, it is important to analyse the distribution and change in weather conditions across the country. This case study addresses...

Erosion of tidal turbine blades in the marine environment is a major material challenge due to the high thrust and torsional loading at the rotating surfaces, which limits the ability to harness energy from tidal sources. Polymer-matrix composites can exhibit leading blade edge erosion due to marine flows containing salt and solid particles of sand...

Erosion-corrosion maps rarely take into consideration the role the rebound velocity has in extending the transition boundaries. Furthermore, although impact angle is an important and widely studied variable in experimental erosion-corrosion mapping, there have been few studies on theoretical treatments of this variable on such maps. In addition, th...

In renewable energy, wind capture has been expanding to now have one of the largest presences in the global green energy sector. With the drive to expand low carbon technologies; maintenance of the engineering components of wind turbines is crucial and in particular the monitoring of the leading edge of turbine blades which experience high impact v...

The effect of chloride on erosion-enhanced corrosion was studied experimentally and by a multiphysics algorithm developed to describe the erosion-corrosion interactions. API 5 L X65 steel was exposed to a slurry jet of different chloride content (0.005, 0.05 or 0.5 M) containing silica particles (250–350 μm). An electrochemical-transport-reaction m...

Raindrop erosion is a significant materials limiting issue. It can affect materials for transportation and renewable energy converters such as wind turbines as well as all external structures used in the construction industries. In such cases, the raindrop effects can occur over a wide range of impact velocities and particles sizes. In understandin...

The micro-abrasion wear mechanisms for CoCrMo against variable size alumina balls, representing typical artificial femoral head sizes, were investigated over a range of applied loads in foetal calf serum solution. SEM analysis of resulting wear scars displayed two-body and mixed-mode abrasion modes of wear. The wear factor, κ, was found to range be...

Wear and corrosion in artificial hip replacements are known to result in metal ion release and wear debris induced osteolysis. This may lead to pain and sensitivity for patients. This infers that pre-clinical testing is critical in determining the long-term performance, safety, and reliability of the implant materials. For this purpose, micro-abras...

Chromium (Cr) containing steels were tested to analyse corrosion behaviour in carbon dioxide saturated water of varying salinities with extended exposure time. Both potentiodynamic and mass loss data were collected to gain a better understanding of the corrosion mechanisms. It was found that both the high Cr steels displayed degradation in the form...

Climate change is rapidly forcing the world to create renewable energy that is capable of sustaining future energy requirements globally. The generation of renewable energy at a comparatively lower cost is a major challenge for this industry. Unforeseen weather conditions and environments such as offshore conditions or involving acid rain have a si...

In the industry of renewable energy, wind has been expanding to become one of the biggest markets. With this increase in popularity, the maintenance of wind turbines is crucial, especially the care of the turbine blades. Rain erosion is widely accepted as one of the key areas of interest, as a even a 2-3% loss in annual energy output significantly...

Wind turbine blade damage, particularly leading edge erosion, is a significant problem faced by the renewable energy industry. Wind turbines are subject to a wide range of environmental factors during a 20 + year lifespan, with hailstones often touted as a key contributor to the deterioration of the blade profile. An experimental campaign was carri...

This paper represents the investigation of rain erosion on wind turbine blade materials under load in the simulation of onshore and offshore environmental conditions. The experimental work was carried out on a whirling arm rig with the material under a static 3 point bend to simulate large multi-megawatt wind turbine blades flexing during operation...

Selection of a water deoxygenation method presents some challenges due to the broad range of options including physical, chemical, electrochemical and biological techniques. This communication presents the design of an apparatus developed for efficient and simple deoxygenation of water for the purpose of electrochemical corrosion studies in a lab e...

This paper presents a study of the erosion resistance of coated and uncoated polymer matrix composites for tidal turbine conditions. It focuses on the development of comparative erosive wear mode and mechanism maps for such materials. In our earlier work, i.e. testing of glass fibre reinforced polymer composites for tribological applications in mar...

This paper represents the investigation of liquid impacts on wind turbine blade materials in the simulation of onshore and offshore environmental conditions. G 10 epoxy glass laminate was used as a specimen material. The experimental work was carried out on a raindrop erosion test rig at the varying angles of attack for a range tip speed. Two solut...

Synergistic effect between corrosion and wear has been widely recognized in many tribo-corrosion systems. In most wet application conditions, dissolved oxygen (DO) is a controlling factor to the dynamics of corrosion process and is therefore expected to have significant impact on the tribo-corrosion performance of materials. In this study, the effe...

There has been significant progress in implant research during last the 10 years (2005–2015). The increase in the elderly population coupled with a lack of proper physical activity is a potential cause for the sudden increment in implant usage. Implant life and performance are influenced by several parameters; however, literature showed that corros...

Tribology in marine renewable technologies has become of increasing interest due to the implications for developing improved materials for tidal and wave energy conversion devices. This on-going research mainly focuses on tidal devices; the materials of interest are primarily polymer-based composite materials that are used to provide structural int...

Tidal energy, of all marine renewables energy, possesses higher persistency and predictability over long-time scales. Moreover, the higher density of water than air also results in greater power output from a tidal turbine than a wind turbine with similar dimensions. Due to the aggressive marine environment, there are barriers in the development of...

Leading edge erosion of wind turbine blades is an important issue within the industry and has been found to have a substantial impact on the annual energy output of generators. This forces operators to make blade repair a necessity, adding to the operation and maintenance costs of a project. A wind turbine’s tip speed can in some cases have an uppe...

Tribology in marine renewable technologies has become of increasing interest due to the implications for developing improved materials for tidal and wave energy conversion devices. For tidal devices, the materials of interest are primarily polymer based composite materials that are used to provide structural integrity while reducing weight. These a...

Material losses in slurry handling systems constitute a significant fraction of cost in oil sands, mining, and mineral processing operations. It is thus important to better understand wear attack mechanisms and major factors affecting wear in such applications. In this work, a methodology and a testing system have been developed to study the abrasi...

The role of salivary media is essential during mastication and ingestion processes; yet it can hinder the performance of foreign materials in the oral cavity. The aim of this study was to examine the effects of applied load and applied electrical potential on the tribo-corrosion mechanisms of 316L stainless steel in an environment similar to oral c...

Wear maps were developed following a series of micro-abrasion-corrosion testing during idealised hip contact conditions for a CoCrMo alloy in a foetal calf serum solution. The main aim of the study was to characterise wear-corrosion or bio-tribocorrosion regimes of the alloy over a range of applied loads and applied potentials. The transitioning mi...

Wind turbines can be subject to a wide range of environmental conditions during a life span that could conceivably extend beyond 20 years. Hailstone impact is thought to be a key factor in the leading edge erosion and damage of the composite materials of wind turbine blades. Using UK meteorological data, this paper demonstrates that the rotational...

The fourth International Conference on Tribo-Corrosion was held in Glasgow from 9–11 April 2014 and had a distinctively Gaelic flavour, with the city of Glasgow being the gateway to the Gaelic traditions encapsulated in the Highlands and Islands of Scotland. An electic group of participants took part in the conference from 23 countries which was th...

In this work, a fundamental study of the wear transition regimes with respect to sliding speed and normal load was carried out for a pin-on-disk sliding couple, involving hardened steel (disks) and titanium base titanium carbide composite coatings (pins). The coating was deposited using a Tungsten Inert Gas (TIG) welding torch melting process. The...

A fundamental study of wear transition regimes was carried out for a pin-on-disk sliding couple, involving titanium and steel. The sliding speed was varied from 0.38 to 1.5 m s-1 and the normal load from 10 to 50 N. Wear mapping approaches have been undertaken to represent the transitions in wear modes and wear mechanisms regimes, as a function of...

In this work, a study of the wear transition regimes was carried out for a pin-on-disk sliding couple, involving two steels of different hardness and Cr contents. Dry sliding wear behaviour of the more highly alloyed stainless steel was dominated by adhesive wear and tribo-oxidation at relatively low sliding speeds and by mixed and adhesive wear at...

The number of joint replacement procedures is expected to increase with an ageing population that is rising annually [1]. In hip replacement devices, wear remains the primary mode of failure in-vivo and an on-going challenge for orthopaedic manufacturers, clinicians and tribologists. Such devices operate in a biological environment under tribo-corr...

Load bearing implant prostheses such as orthopaedic hip and knee implants may be considered as tribocorrosion systems since the wear processes are a result of combined mechanical and chemical mechanisms. The long-term success of implant prostheses depends on a number of factors, including age, body weight and activity levels. Pre-clinical testing i...

Stainless steel can be used as a dental implant. However, there has been little work on the micro-abrasion of such materials in laboratory simulated oral environments, where abrasion, sliding wear can interact simultaneously. In this study, the effects of applied load, and exposure time were evaluated for a 316 stainless steel in a laboratory simul...

Dry sliding wear (pin-on-disc) tests were carried out under ambient conditions at room temperature for TiC coated and uncoated 303 stainless steel, using alumina as a counterface. The composite coating which was developed by Tungsten Inert Gas (TIG) methods increased the surface hardness of the substrate and the sliding wear resistance of the subst...

The growth kinetics of tetragonal and monoclinic ZrO2 crystallites in 3 mol% yttria partially stabilized ZrO2 (3Y-PSZ) precursor powder has been investigated using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area analysis, transmission electron microscopy (TEM) and high resolution TEM (HRTEM). After calcination of the 3Y-...

The phase transformation behavior of freeze-dried 3 mol% yttria-partially-stabilized zirconia (3Y-PSZ) precursor powder has been studied. When the freeze-dried 3Y-PSZ precursor powder was calcined at 773-1073 K for 2 h, the crystalline structure was composed of tetragonal and monoclinic ZrO2 as primary and secondary phases, respectively. The freeze...

Tribocorrosion affects all walks of life from oil and gas conversion to biomedical materials. Wear can interact with corrosion to enhance it or impede it; conversely, corrosion can enhance or impede wear. The understanding of the interactions between physical and chemical phenomena has been greatly assisted by electrochemical and microscopic techni...

The micro-abrasion of Y-TZP, a candidate dental restorative material, was investigated in a range of caffeine-containing solutions which included tea and coffee. Additions of sugar and milk were used to test the effects of viscosity and pH on the wear rate. The results indicated a significant increase in wear rate in the various solutions, with som...

The increasing developments in wind turbine technology, coupled with an unpredictable operating environment, present significant challenges regarding erosion issues on the leading edge of the blade tips. This review examines the potential degradation posed by the different environmental variables, with specific emphasis on both rain droplet and hai...

Tribo-corrosion is an emerging interdisciplinary subject that spans from basic research on the behavior of surfaces in mechanical contact in chemically active surroundings to the test methods needed to quantify its effects, and from the selection of materials for bio-implants to the minimization of surface degradation and wastage in advanced energy...

Previous investigations into the erosive-corrosive wear of metals in aqueous conditions have concluded that the process is best described by discrete wear regimes. Such regimes identify the dominant wear process that is causing wastage of the target material. Primarily, the regimes are categorized by the dominating electrochemical process, whether...

The scale of modern blades means that tip speeds in excess of 100ms-1 are now common in utility scale turbines. Coupling this with a hailstone terminal velocity ranging from 9ms-1 to 40ms-1, the relative impact velocity becomes highly significant. There is little published data on the performance of blade materials under these impact conditions and...

The objective of this work is to investigate the micro-abrasion of Y-TZP in tea. This material is a candidate replacement in dental restoration and to date there has been very little work carried out to investigate the wear behaviour in oral cavity conditions. Various additions such as milk and sugar, which affect the solution viscosity and pH, wer...

The scale of modern blades means that tip speeds in excess of 100ms -1 are now common in utility scale turbines. Coupling this with a hailstone terminal velocity ranging from 9ms-1 to 40ms-1, the relative impact velocity becomes highly significant. There is little published data on the performance of blade materials under these impact conditions an...

In previous studies of erosion-corrosion, several different theories have been developed to produce a model which represents the relationship between particle erosion and chemical corrosion. Regimes in the models define how the two mechanisms behave relative to one another, whether it is erosion dominated, corrosion dominated. This paper investigat...

The effects of rain and hail erosion and impact damage on the leading edge of offshore wind turbine blades have been investigated. A literature review was conducted to establish the effects of exposure to these conditions and also to investigate the liquid impact phenomena and their implications for leading edge materials. The role of Explicit Dyna...

The use of technologies related to combustion of coal in fluidized bed combustors (FBCs) present attractive advantages over conventional pulverized coal units. Some of the outstanding characteristics are: excellent heat transfer, low emission of contaminants, good combustion efficiencies and good fuel flexibility. However, FBC units can suffer mate...

A CFD (computational fluid dynamics) model has been developed to evaluate the effects of particle concentration on the erosion–corrosion of the inner surfaces of a circular pipe of 90° bend at room temperatures. The relative intensity of erosion and corrosion around the pipe geometry results in transitions between various erosion–corrosion regimes,...

The micro-abrasion-corrosion behavior of a Ti alloy in Hank's solution was investigated using various electrochemical and microscopy techniques. The effects of applied load and particle concentration were assessed for various corrosion, wear and wear-corrosion components of the wastage. Electrochemical potentiodynamic and potentiostatic tests were...

The process of micro-abrasion–corrosion has been the subject of much research in recent years due to the fact that the action of micron sized particles, typically less than 10μm in diameter, can cause significant degradation of materials in many diverse environments involving aqueous corrosion. Cermet based coatings are often used to combat micro-a...

In studies of the interactions of erosion and corrosion, there are many variables which may affect the wastage rate, i.e. relating to properties of the impacting particles, the target and the environment. In this chapter, an overview is presented of models of solid particle erosion for metallic materials, metals and composites. Combining erosion mo...

The threshold velocity for erosion of a ductile material is considered as the velocity required for initiation of plastic deformation in the substrate. For a brittle material, it defines the velocity required to nucleate a median crack in the elastic/plastic interface beneath the indentation. By invoking models for the solid particle erosion of duc...

In this study, the erosion–corrosion performance of carbon steel was investigated in crude oil, reservoir water, and a mixture of both solutions at a range of applied potentials, velocities and impact angle. The application of such work is to upstream and downstream oilfield conditions, where the proportions of hydrocarbon and water may vary during...

The object of this work was to evaluate the particulate erosion performance of Y-TZP (Yttria Tetragonal Zirconia Polycrystalline), used in the construction of artificial teeth, at various pH values, impact angles and exposure times. The results showed that the highest degradation recorded was in acidic environments. However, the incubation time to...

Decorative coatings require not only an attractive appearance for market applications, but also an ability to protect the surface underneath. Because of this, corrosion, wear and their combined effects (termed tribocorrosion) are particularly important for lifetime prediction. In this paper, the tribocorrosion behaviour of a range of single layered...

In this paper, a model is generated of the effect of temperature on the erosion–corrosion of Fe in aqueous conditions, for room temperature to 373K. The results indicate how the transition from active to passivation dominated regimes for Fe is favoured as the temperature is increased. 2D and 3D maps are constructed showing the transitions between e...

Tribo-corrosion mechanisms of 316L Stainless Steel in slurries containing common household soft drinks have been studied through investigating the micro-abrasion–corrosion performance using a ball and disk apparatus which has been modified to measure the in situ corrosion current during the abrasion process. The objective of this study was to evalu...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The low-stress three body abrasion behaviour of a range of steels was investigated. The tests were carried out in a rubber wheel tester (according to ASTM G65-94, reapproved in 2000) at room temperature. The abrasive particles used were angular alumina particles of four different sizes. The results showed that, in general, the smaller particles (50...

Erosion by solid particles in oil/water slurries is a technologically important area. In such conditions, it is necessary to distinguish between the effects of the sand, aqueous environment, and the oil. Erosion–corrosion maps provide a means of identification between erosion–corrosion regimes as a function of erosion and corrosion parameters. Howe...

The 2nd International Symposium on TriboCorrosion was held on the 17th and 18th of March 2009, at the Austrian Center of Competence for Tribology. TriboCorrosion is an interdisciplinary subject and it encompasses diverse aspects such as mechanical engineering, physics, chemistry, material science. The symposium was attended by more than hundred del...

In studies of tribo-corrosion, the degradation of bio-materials has become of increasing research interest in recent years. This is because, in many cases, the interactions of the tribological and corrosion component in biological environments are not well understood. Moreover, the wide range of variables involved in the tribo-corrosion process, an...

Erosion–corrosion of materials in aqueous environments is a complex phenomenon involving a very large number of variables. In such cases, characteristics of the target, particle and the environment affect the degradation mechanism. Predicting material behaviour may sometimes be a “black art” due to the parameter size which is involved in such proce...

Nanoscale CrN/NbN multilayer PVD coatings have exhibited resistance to erosion–corrosion. However growth defects (under dense structures and droplets) in the coating produced by some deposition technologies reduce the ability to offer combined erosion–corrosion resistance. In this work a novel High Power Impulse Magnetron Sputtering (HIPIMS) techni...

In studies of erosion-corrosion, much work has been carried out in recent years to identify regimes of behaviour. Such regimes describe the transition between the erosion and corrosion dominated mechanisms. They can also be used, by assigning various criteria, to identify other regimes of behaviour such as extent of "synergy/antagonism" in the proc...

There is increasing interest in the interactions of microabrasion, involving small particles of less than 10 mm in size, with corrosion. This is because such interactions occur in many environments ranging from the offshore to health care sectors. In particular, microabrasion–corrosion can occur in oral processing, where the abrasive components of...

The 1st International Conference on Tribo-Corrosion was held in Hyderabad in India between 4 and 6 December 2006. The conference was hosted by the NFTDC (Non Ferrous Materials Technology Development Centre) in Hyderabad who organized a truly special programme events. A kaleidoscope of colour from the gardens surrounding the Institute, lit up specia...

Materials exposed to aqueous slurry environments must not only resist the impact of solid particles and the flowing environment but also the degradation caused by electrochemical corrosion. In this study, the combined effects of slurry particle concentration and velocity on the erosion–corrosion of a WC/Co–Cr coating were assessed at a range of ele...

The area of micro-abrasion is an interesting and relatively recent area in tribo-testing methodologies, where small particles of less than 10μm are employed between interacting surfaces. It is topical for a number of reasons; its direct relation to the mechanisms of the wear process in bio-tribological applications, ease in conducting tests and the...

The contribution that a Physicist can make to Tribology will be greatly increased by effective and enlightened collaboration with the chemist, metallurgist and engineer. David Tabor (1913–2005) The first meeting of the Institute of Physics Tribology Group was held at Cranfield, UK, in 1980 entitled 'Tribology: Contrasts in Frictional Processes'. Th...

Very little research effort has been directed at development of models of erosion–corrosion of composite materials. This is because, in part, the understanding of the erosion–corrosion mechanisms of such materials is poor. In addition, although there has been a significant degree of effort in the development of models for erosion of MMCs, there are...

In studies of erosion-corrosion of composite-based coatings, there has been an extensive research carried out in recent years. This is because such coatings, which contain hard particles as reinforcements, have the potential to provide an improvement in mechanical properties compared to the un-reinforced base material. In addition, composite-based...

Corrosive species in various forms exist widely in the environment and can significantly affect wear behaviour of materials, usually accelerating wear. Under conditions where the environments are seemingly non-deleterious in terms of corrosivity, some species from the environment can still affect the tribological behaviour of materials. It is thus...