Reliability and design of functional ceramics

The challenges we tackle in materials technology with our in-depth understanding of mechanisms, multiscale simulation, and atomistic calculations:

• Improving fracture toughness, e.g., through microstructure design, doping, or composite structures, because piezoceramics such as PZT (lead zirconate titanate) are brittle and prone to cracking under mechanical or thermal stress.
• Under continuous electrical stress, piezoceramics lose their polar properties over time. Ageing resistance can be improved by varying the compositions, e.g., through targeted doping with acceptor/donor atoms.
• To counteract electrical fatigue and materials fatigue under cyclic stress (mechanical or electrical), fatigue-resistant microstructures, e.g., with fine-grained or textured structures, are necessary.
• Grain boundaries play a decisive role in electrical conductivity and polarization behavior. These properties can be improved by controlling the grain boundary chemistry and structure, e.g., using sintering aids or controlled atmospheres during firing.
• Many high-performance piezoceramics contain lead (e.g., PZT), which is problematic from an environmental and regulatory perspective. It is therefore important to identify and evaluate lead-free alternatives with comparable performance (e.g., based on KNN – potassium sodium niobate).
• Diffusion of electrode materials (e.g., silver, copper) can damage the ceramic. Diffusion resistance can be improved with barrier layers or suitable selection of materials.

To tackle these challenges together with you, we calculate the properties of your materials systems and develop the appropriate simulation methods for them. Our aim is to create a sound understanding of mechanisms with a reasonable amount of computing power. This opens up new possibilities for you in terms of materials design.