Laboratory sheet

Research topics :

• As the demand for developing environmentally friendly and energy efficient technologies increases, it is critical to devise processes for the production of materials which match those demands at lower costs. In this context, flash sintering (FS) can overcome conventional sintering issues, leading to a reduction of the processing time from days/hours to min/seconds, while decreasing the operation temperatures. Among the candidate materials suitable for flash-sintering, this project focuses on yttria stabilized zirconia (YSZ), because it is widely used for fuel cells, one of energy technologies that is critical for public transportation and the automotive industry. In this work, nanoparticles of YSZ will be deposited in a transmission electron microscopy (TEM) grid, to simulate in real time the process of flash-sintering. In particular, the nanoparticles will be subjected to different electric fields and processing temperatures, while the mechanisms can be monitored in real time, inside an advanced TEM.

• Potassium-Sodium-Niobate (KNN) is getting increasing importance as lead-free piezoelectric functional material. However, monophasic dense KNN products are yet difficult to obtain and this project proposes a new method to densify materials abruptly above a threshold condition, FLASH sintering (FS), using a combination of temperature and electrical field directly applied to the specimen. A clear understanding of the phenomena does not exist yet. The present work aims to exploit FS and study the science behind it with the following objectives: (i) To investigate the dependence of FS on KNN dimensionality (bulk, films, nanoparticles) (ii) To identify the densification mechanisms in KNN FS and effects of electrical field (iii) To develop alternative sintering techniques for functional oxides aiming to decrease the thermal budget (iv) To prove the concept for low temperature sintering of KNN thin films on flexible substrates, never explored by FS, and extend it to other lead free oxides.

Contact information:

Paulo Ferreira

Ph: +351 253 140 112

Email: paulo.ferreira@inl.int

Leonard Francis

Ph: +351 253 140 112

Email: Leonard.Francis@inl.int