Extending the OE
When David Williams left New Zealand in the mid-1970s, he was anticipating a two-year OE and hoping for a change in direction after his PhD in electrochemistry. More than three decades later, he finally returned home in 2006 to take up a position at his alma mater, the University of Auckland, and to join the research team at the MacDiarmid Institute for Advanced Materials and nanotechnology. In between lay exceptional academic achievements, several successful businesses and more than 40 patents — and an enduring fascination with chemistry.
David’s first stop-over as a young graduate who “had enough of electrochemistry for a while” was Oxford University and a research team using nuclear magnetic resonance spectroscopy. “I learned to distinguish between a Burgundy and a Bordeaux by smell, but I wasn’t very good at NMR spectroscopy,” he says. And so a year later he moved on to Imperial College London to join a team working on the extraction of metals from low-grade sources and waste products. As part of the extraction process he used molten salt heated to 1300°C, not far from its boiling point. “I’d put things into the furnace in little steel capsules. They’d get white hot and then I would tip them straight into liquid nitrogen. People used to watch me from a safe distance!”
This experience led to “a real job” at the metals company IMI Titanium, which made titanium alloys to be used as corrosion resistant materials for containers and in aircraft production. “As part of diversifying the business, the company got into electrochemistry using titanium and its intermetallic compounds as electrodes in the extraction and purification of metals. They began developing oxygen-evolving anodes for use in the electrowinning of copper and cobalt. I was involved in that, using intermetallic compounds such as titanium nickel, which proved a particularly good material for these anodes.”
In 1981, David Williams had what he sees as his major career break when he joined the UK Atomic Energy Research Establishment at Harwell. “It was a superb materials science lab at the time, with 4000 researchers. I worked in the chemical sensors group, but half my time was spent on fundamental research to support nuclear power, and that’s where I started my work on corrosion.”
Nuclear power plants use stainless steel to contain radioactive solutions, but under certain circumstances, stainless steel can be less than stainless and vulnerable to small-scale localized corrosion. Manganese is added to stainless steel to help with processing properties, but it scavenges sulphur from the steel, resulting in tiny inclusions of manganese sulphide.
“The critical corrosion is localised corrosion,” says Professor Williams. “You can get a source of local corrosion around an impurity in the stainless steel, and it works its way all the way to a hole. This kind of localised corrosion is random in time and space, so it’s been very difficult to study.”
Professor Williams says his contribution to solving the problem was to introduce measurement processes and methods to quantify this kind of localised, or pitting corrosion. “It’s measured by looking at small fluctuations in current. Experiments showed tiny fluctuations well before there is noticeable corrosion, and I was able to correlate that with the chemistry and microscopy of the materials.”
His work on corrosion led to the development of techniques of in-situ microscopy, which allowed him to observe corrosion in action. He used scanning laser microscopy and electro-chemical scanning probe microscopy to show that the key chemistry of the corrosion process is happening right at the edge of the manganese sulphide impurities. In 2002, the research and further work to quantify the effect was published in the prestigious science journal Nature.
“The quality of stainless steel has improved enormously since we began this work, and the content of sulphur is much reduced, but localised pitting corrosion remains an ongoing problem and concern. It’s an ongoing stream of my research to improve the measurements of composition around these inclusions, and it’s an active topic I am now working on in collaboration with colleagues at the University of Western Australia.”
Looking back at this time in his career, Professor Williams credits the research laboratories at Harwell with offering one of his greatest opportunities. “The work was interesting, my publication rate shot up and the smartest people were there. There were two doors to the canteen, one at the front and one at the back. I would use the back door to spot who was there and what kind of conversation I would like to have on any particular day.”
The abundance of talent and multi-disciplinary mix of research topics meant that many problems could be brainstormed, and often solved, over lunch or coffee.
Apart from the corrosion research, he was also able to build on his work on chemical sensors for gases, based on semiconducting oxides, which led to the discovery of several chemical compounds that were particularly suitable. However, the Harwell institute was privatised during the Thatcher era, and so it was time for the next move to University College London, where he became Thomas Graham Professor of Chemistry and later head of the chemistry department. During this time, Professor Williams made his first forays into private business.
“We were looking into commercialising our research on gas sensors, and with venture capital funding we set up a company called Capteur Sensors. Over eight years we developed it to a level of sales of one million sensors a year. Eventually, it was sold for nine or ten million pounds.”
Even his modest one percent share in the company was enough to buy a house in Katikati in 2000, and to begin his slow return to New Zealand. First though, on visits back, he helped to start another company. Aeroqual Ltd, based in Auckland, uses the same type of gas sensors to build instruments to monitor air quality and gases in the atmosphere. Using private fi nance this time, the team developed its first instrument to measure ozone. “It has the performance of the big analytical instruments for measuring ozone in the air but it’s much smaller, lighter and cheaper. It can even be flown on balloons to measure ozone in the stratosphere.”
An instrument to measure nitrogen dioxide, another compound local authorities are required to monitor, was next, and another one with a high sensitivity for volatile hydrocarbons in the air is under development in collaboration with Christchurch-based Syft Technologies.
“And then, back in London, I was drinking beer in the back garden with a friend who’d developed a home-kit device to measure glucose. His company had just been sold, and he asked whether I’d want to be part of the next adventure.”
The aim of this next business venture was to develop devices to measure cardiac markers, or heart hormones, to provide a quicker diagnosis of heart disease. But in a quick procession of further business transactions, Professor Williams found himself chief scientist of Inverness Medical Innovations and embarking “on a big learning curve to learn how to work with immuno-assays and using antibodies to measure markers”.
It was amidst this busy time that a conversation with Jim Metson, another principal investigator with the MacDiarmid Institute, led to an invitation to come back to the University of Auckland, and to tackle a suite of other challenging chemistry problems. “For the MacDiarmid Institute I’m now working with antifreeze peptides from Antarctic fish. They work by changing the shape of ice crystals, and the most effective peptides are those that have sugars attached. They are easy to study and the system can be easily manipulated chemically.”
Professor Williams says he’s happy to be back and working among a group of great people, but after 32 years in the UK, his strong connections with research teams there will continue extending his big OE for some time yet.