Engine components can over time develop ‘coke formations’ which can lead to increases in temperature causing cracking of components, blockages and engine failure. Coked components have poorer thermal conductivity, can reduce efficiency and the lifespan of engine components through increased wear, so lubricants not only act to reduce friction of such components but also play a key role in engine thermal management and cleanliness.

Both visual and X-ray imaging are often used to assess the performance of lubricating oils during engine testing and studying ‘carbon deposits’ which are the natural by-product of burning gasoline in gasoline engines. Although there are challenges regarding both of these methods, visual assessment can often mean vital information can be missed. In small objects, X-ray imaging is available to achieve the correct contrast between the low-density material and high-density substrate, but the large scale of engine components means that X-rays are strongly absorbed and inner surface deposits are often obscured. Assessing internal deposits are currently left to destructive methods, as often the component must be cut open and damaged therefore preventing continued use.