Totally superficial

What we consider to be a negative character trait has a thoroughly positive connotation for materials scientists. Because, chemically speaking, it's what happens on the surface that counts. Whether it's biological compatibility in implants, antibacterial coatings in hospitals, or catalytic processes in the production of, say, synthetic fuels – surfaces are crucial to all of these.

And it is often the surfaces that are responsible for very specific properties of the material. This is the basis for various high-tech coating technologies that can be used to produce piezoelectric thin films, for instance, which are widely used in microelectronics and are also likely to play a decisive role in future quantum technologies and photonics applications.

Sometimes coatings are “only” there for protection. Certain oxide layers are just as important in high-strength steels, where they prevent “hydrogen embrittlement” and thus ensure stability, as they are in titanium implants, which are protected from biocorrosion in the very same way. This is because our bodily fluids are a surprisingly aggressive environment, even for materials as robust as titanium.

Of course, it is always worthwhile to look beyond the surface and get to the bottom of things. For the current issue, however, we are actually only scratching the surface – because even that holds enough secrets ...

Michael Hagmann
Head of Empa communication