Using New Techniques to Understand Corrosion

In this interview, Professor Philip Withers, Regius Professor of Materials, University of Manchester, talks to AZoM about the ESPRC Prosperity Partnership Project he is leading, and how it is tackling the issue of corrosion.

Can you give a brief overview of the recently announced EPSRC Prosperity Partnership Projects, which you are leading?

It is a brand-new scheme that the EPSRC have developed. Indeed it is the first time they have run something like this where they have set up a competition for large companies to work with universities and I think they were overwhelmed by the number of proposals they got. Our project builds on an existing relationship between BP and The University of Manchester through the BP International Centre for Advanced Materials (BP-ICAM) which is a $100m research centre involving Manchester, Imperial College London, the University of Cambridge and the University of Illinois at Urbana-Champaign. At BP-ICAM, we already have a team of people from all of these different organisations working together on corrosion and wear but we identified that, to move forward, it wasn’t simply good enough to just look at existing lubricant and methods of preventing corrosion.

Image Credits: International Centre of Advanced Materials

We needed to go right back to first principles. We said, “What we have got to do is understand the very early stages of corrosion and understand how corrosion films nucleate and grow.” If we can understand this, we can stabilize corrosion. Most people do not realize that corrosion films are very important. They provide a protection to metals. The only reason you can pull two pieces of aluminium foil apart is because the oxide between them is preventing one piece of metal joining to the other. Understanding stable films is really important. The problem is; these stable films that you get on aluminium, they protect aluminium, but in steels and other materials they often break down. When they start to break down you get localized pitting. Understanding that localized corrosion is really important.

You mentioned that the Universities of Manchester, Cambridge and Imperial College already collaborate with BP on corrosion research through the BP-ICAM.  What are the strengths of these three university partners and what new areas of expertise do Leeds and Edinburgh bring to this EPSRC project?

We are putting together a piece of work to really understand how these films form, and how they break down. As you mentioned, we have got our existing partners of The University of Manchester, the University of Cambridge and Imperial College London working on this project, who each bring an area of expertise. At Manchester we have experts in the area of corrosion scales and corrosion imaging and characterisation. At Cambridge we have experts in the area of surface science and at Imperial we have strengths in multi-scale modelling.  We have also identified key skills at the University of Leeds in the area of tribocorrosion, or corrosion wear and we have added the University of Edinburgh to bring in specialized techniques for looking at materials behaving under really high pressures. They help the project because when you have an oil film, and you have a harsh and demanding environment, then you need to be able to understand how the films behave under this extreme mixture of environment and load.

What techniques are you using in the project to take a more forensic approach?

People have historically studied corrosion empirically. They have measured growth rates and they have looked at pitting to try to understand that. What we are doing is bringing some novel techniques, like x-ray imaging and synchrotron radiation science, to probe into what is going on at these early stages. These new techniques, coupled with an ability to model across the length scales, mean we can now model in a way we could never do before. It means what we will be trying to do is to shed new light on these early stages, and if we can grow stable films we will be able to reduce the corrosion rates, which is in everybody’s interest.

Your personal area of expertise lies in imaging and characterization of materials across a wide range of length scales. Could you explain more about how this works and how these advanced techniques are being applied in the project?

I am sure everyone knows about x-rays. Superman had x-ray eyes, well, now Doctors have x-ray eyes too. X-rays penetrate materials and we can use those x-rays to probe the near surface region to understand how these films are growing and how this damage is accumulating. The x-rays allow us to study materials in situ. Traditionally, if you want to study a region of corrosion, you must take it out of the environment and clean it up first. You have to cut it up and you have to look at it under very idealised conditions. Now that is fine, but that is very unlike what the corrosion is actually experiencing. With x-rays, we can look at a surface in the environment and we can understand how the corrosion is taking place in real time. So, we get kind of 3D movies of the corrosion events taking place. By watching what is going on, we can understand better about why those particular sites are corroding. You might have a pipeline that is thousands of miles long and corrosion only happens in certain locations. You may ask, “Why does it happen there? What is it about this particular part of that environment that is triggering corrosion there?” X-rays are a good way of looking at what is going on in situ.

Will both BP and the oil and gas industry benefit from this?

Of course, corrosion is everywhere. Traditionally we have had to manage it. That means you have to take things out of service after a certain length of time. Of course, in the worst-case scenario, you get unexpected failures where corrosion happens faster than you would expect and that can be an environmental problem, but also an economic problem. BP has a very significant interest in the safe and economic operation of plants.

Image Credits: shutterstock.com/Oil and Gas Photographer

BP also makes Castrol GTX. Every car owner is very aware that wear and corrosion can affect the performance of their car. If we want to have greener, lower energy transport, we need to have lubricants that work more efficiently because energy is lost when surface rubs against another. You want low friction surfaces that will glide over one another with the minimum amount of damage and the maximum amount of ease and so oil is a very important element towards environmentally friendly cars.

That is the benefit for BP.

But, as I said, corrosion is all around us, so there are many other industries that will benefit. Whether that is in energy production, the marine sector or the aerospace and automotive sector. Corrosion can also be important in the medical sector as we have a lot implants working in extreme, very unusual conditions, and so we need to be able to have safe materials for biomedical components, as well as for these heavy engineering components that BP is interested in.

Why is it so important for universities to work in collaboration with the industries that solve global challenges such as corrosion and wear?

One of the things I always say to my material science students is that when I was a student, new materials meant going into space and doing exciting things like that. But many of the world’s real problems today relate to things like clean water, greener energy production and so forth. All these challenges have materials right at their core. For example, the battery. I am sure everyone has seen batteries corrode and when they do, they can corrode very dangerously.

Image Credits: shutterstock.com/agrofruti

Understanding corrosion and oxidation are very, very important to the materials of the future. As well as understanding how to manage older components that are already in place, we also need to be able to design new materials with new coatings and with new treatments that will allow them to last much longer. These are global challenges which universities can help provide solutions for.

Where can our readers find out more information about this project?

The EPSRC’s website has some information about this project and there is even a short film about this project that they might find interesting.

About Professor Philip Withers

Professor Philip Withers FRS, FREng, FRAes, FIMMM read Natural Sciences and completed his PhD at the University of Cambridge in the 1980s focusing on mental matrix composites for his PhD. In 1989 he became a lecturer in Materials Science and Metallurgy at Cambridge before being appointed to a Chair at The University of Manchester in 1998.

He is particularly interested in how things fail and how to design materials that are stronger, operate at higher temperatures or will last longer. In 2008 he established the Henry Moseley X-ray Imaging Facility which is now the most comprehensive suite of 3D X-ray imaging systems in the UK. In September 2012 he became the founding Director of the $100m BP International Centre for Advanced Materials (BP-ICAM) and in 2017 the Chief Scientist for the £235m Henry Royce Institute.

He is a Fellow of Royal Society (2016), the Royal Academy of Engineering (2005), the Royal Aeronautical Society (2008) and the Institute of Materials, Minerals and Mining (2004). In 2016 he became the first Regius Professor of Materials in the UK.