Surface Engineering: Origins, Status and Potential
Following his Inaugural Lecture, Ros Dodd met Professor Hanshan Dong to find out more about the internationally leading Birmingham research addressing the challenges of materials engineering.
Growing up in China’s so-called Cultural Revolution, Professor Hanshan Dong had little hope of a good education as all the universities were closed.
The fact he went on to become a world-leading academic in his field makes his achievements even more remarkable.
Hanshan has made ground-breaking contributions to the surface engineering of titanium-based alloys: his novel ceramic conversion technology made it possible, for the first time, to use titanium components in engines and cars for Formula One and IndyCar racing.
Recently appointed Chair in Surface Engineering, he is currently working on developing anti-bacterial stainless steel food processing and medical equipment that could help to eradicate super-bugs.
‘I get inquiries from around the world from people wanting me to help them solve problems with titanium,’ he says.
Born in Shanghai, Hanshan was at primary school when Chairman Mao set in motion the Cultural Revolution in 1966.
‘We had no formal lessons; it was a real problem for my generation growing up in China at that time,’ he recalls.
‘The universities were closed for ten years, so I got a job as a technician in a small manufacturing company.’
It was coming up against work problems he couldn’t solve that made Hanshan want to learn more about engineering. When the universities reopened in the late 1970s following the reforms implemented by Mao’s successor, Deng Xiaoping, he beat off stiff competition to win a place at the University of Shanghai, where he gained his first degree, in Metallurgy and Materials Science.
His research interest in surfaces was triggered while doing MPhil studies related to improving the wear properties of bearing steels.
After five years as a lecturer in Shanghai, Hanshan won an Overseas Research Scholarship, which enabled him to come to the UK for a year. He arrived in Birmingham in 1992 – and never left.
‘While I was still in China, I was influenced by the late Professor Tom Bell, who was the founder of the discipline of surface engineering – he was very famous in China. I met him in Shanghai and he’s probably the reason I came to Birmingham.’
Although surface engineering had been practised for thousands of years, it was only established as a discipline in the mid-1980s.
‘Surface engineering – improving the surface properties of materials – is applicable in almost everything we do – from the razors we shave with to the engines that power our cars and the hard discs in our computers. It is also very important for the aerospace industry; without surface engineering, you couldn’t use very high temperatures in engines.’
And, of course, surface engineering is also vital in the motor racing industry.
‘The motor sports industry sponsored my PhD, which was on the surface treatment of titanium.’
Titanium is an attractive metal as it is light and strong – much lighter and as strong as steel. But it has a major drawback: its wear property is extremely poor. When it comes into contact with any other surface, titanium will transfer to the counterpart surface. In other words, it quickly wears away. So without surface treatment, the metal is unusable in many applications.
So Hanshan’s first major research project was to develop two new process patents to treat titanium.
‘The treatment is actually simple, cost-effective and 100 per cent environmentally friendly,’ he explains. ‘What I did was convert the titanium surface into ceramic, because ceramics have much better wear properties. If you heat a titanium component in oxygen containing gas, the titanium will act within the oxygen and form titanium oxides. Titanium oxide is ceramic.’
Because the treatment is in situ conversion rather than applying a coating, there is no risk of it wearing off.
‘Titanium components treated using my technology have been used in racing car engines for years now,’ says Hanshan.
The ceramic conversion process is what he ‘is most proud of’, and in 2004 it won him the Harvey Flower Titanium Prize.
He is now using the same process to treat titanium artificial hip joints, which – apart from the surface wear problem – are much better than stainless steel ones.
However, stainless steel remains a hugely popular material for kitchen utensils and medical instruments.
‘Although the fact it’s stainless is great, the wear resistance of stainless steel is poor, especially austenitic steel. So a knife will soon lose its sharpness. You can use another stainless steel, called martensitic, which is much harder, but the corrosion resistance isn’t very good.
‘So my research group has developed a novel process called “low temperature plasma surface treatment”, which hardens the stainless steel without losing its corrosion resistance.’
Hanshan is now working on what might be his most important piece of research yet – producing anti-bacterial stainless steel surfaces in a bid to eradicate the spread of super-bugs.
‘Silver can kill bacteria, so if you coat a surface with polymer-based paste that contains silver, it will have anti-bacterial properties. However, polymer is very soft, so if you’re thinking about medical instruments and food process equipment, then it’s useless. So what we’re trying to do is to introduce silver into stainless steel using the previously patented process, low temperature plasma surface treatment.
‘We have a patent pending in this area and we’re working with a company – we can’t name them at the moment – and I’m hopeful that we could have anti-bacterial stainless steel products on the market within five years.’