Be it in quartz watches, as injection systems for motor vehicles or in loudspeakers - piezoceramics have been an integral part of modern technology for years. And with good reason, after all, the material has quite extraordinary properties: when pressure is applied to piezoceramics, i.e. when the material is subjected to mechanical stress, it generates voltage. And vice versa: when a voltage is applied, the shape of the material changes.

Researchers from Fraunhofer IKTS and Fraunhofer IZM, together with the Hasso Plattner Institute and the FU Berlin, want to promote the use of piezoceramics, particularly for developments in SMEs, as part of the “Smart Co-Creation” project. In the spirit of Design Thinking, two series of three workshops have already taken place, during which experts and users discussed the application potential of piezoceramics for specific industries.

The first collaborative brainstorming session focused on medical applications: using piezoceramics in intelligent dental implants could improve the monitoring of the implants. Technically, this works as follows: chewing exerts mechanical pressure on the ceramic, which generates an electrical voltage that can be analysed. If there are irregularities or damage in the dental structure, this voltage changes and immediate action can be taken without any major work.

The second series of workshops focused on the use of piezoceramics for monitoring large infrastructures. For example, they can be used to record the vibrations of bridges. Changes in vibration patterns indicate damage. This means that the condition of the bridge can be monitored and repairs can be carried out before serious damage occurs.

However, piezoceramics have one disadvantage: they contain lead, which can escape in the form of dust during extraction and smelting, as well as if the material is improperly recycled, and can enter the water cycle, for example. The consequences for humans and the environment are drastic, as this heavy metal can cause nerve damage even in low quantities.

In order to prevent this, the European Union has issued directives that essentially ban the use of lead in electrical and electronic devices.

However, there are exemptions. Due to the fact that no lead-free ceramic material with comparable performance has yet been developed with the current state of science and technology, exceptions have been made to the rule for piezoceramics. The directives are updated to the state of the art in science and technology every four to seven years, i.e. a review is carried out to determine whether scientific and technical progress makes it possible to substitute lead in piezoceramics, although this has not been the case to date.

Dr Otmar Deubzer, expert in product-related environmental law at Fraunhofer IZM, attended both workshops and ensured that the applications conformed to the European Commission's RoHS, REACh, WEEE and EuP/ErP directives. “Piezoceramics are a wonderful material with characteristics that are really not easy to replace. It is therefore especially important that a realistic and responsible approach is taken right from the conception stage, which will enable piezoceramics to be used in electronic product development in accordance with the legal exemptions. I am very happy to have been able to contribute my expertise to the “Smart Co-Creation” project and look forward to the resulting developments,” said the scientist. Future projects that aim to realise the full potential of the material are already being applied for, thanks to the sharing of ideas.

“Smart Co-Creation” was funded by the German Federal Ministry of Education and Research. The project is managed by Fraunhofer IKTS and is part of the innovation network smart³.

(Text: Olga Putsykina)