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César Steil


On Ceramic Conductivity



© J. Trebosc

He could talk forever about ceramics, cubic zirconia, or ion oxides, but says very little about himself. “Why talk about me?” wonders César Steil in a calm, steady voice. Clearly this research scientist from Villeneuve-d'Ascq1 breaks the stereotype of the Brazilian extrovert. And if he admits that he enjoys soccer, samba, and parties as much as the rest of his compatriots, he also insists that Brazil brings much more to the table: “It also plays an important role in space and nanotechnology research.”

Born to a modest family of shopkeepers in the state of Santa Catarina in southern Brazil, Steil's gifts in math and physics soon became apparent. He received a scholarship for advanced studies at the University of São Carlos with one driving ambition: to become a research scientist. In his second year there and during an internship in a research laboratory, he discovered the exceptional properties of ceramics: resistance to both high temperatures and wear, chemical inertness, etc. This research triggered his interest for these unusual materials, “and even more for their electrochemical properties.”

It was two years later that Steil came to pursue his research in France. “I had long wanted to do my thesis in Europe. Initially I had thought of England.” But in 1991, after his Masters degree, he signed up for a thesis at the Special Ceramics Laboratory of the École des Mines in Saint-Étienne. “I had done a two-month internship there the previous year, and I really liked both the atmosphere and the working conditions.” Splitting his time between Saint-Étienne and Grenoble,2 he studied ionic conductivity of ceramics based on cubic zirconia. “They offer three major applications,” he explains. “First, they can be used to detect the level of oxygen dissolved in molten steel in order to produce a very high-quality stainless alloy. Secondly, they can be used in electrochemical compressors to generate very pure oxygen from ambient air. This solution is of great interest to aircraft manufacturers. And thirdly,” he adds, “they can be used as an electrolyte in solid oxide fuel cells (SOFC), a very popular application these days.” But there is one problem: To be useful, zircon must be heated to temperatures between 800° and 1000°C. Those high temperatures raise issues concerning the choice of assembly materials, reactivity, stability at high temperatures, gas leaks, etc. Current research aims at discovering other ionic conductors at lower temperatures. Steil has focused his studies on the properties of Bimevox, which is a conductor at 700° or even 600° C. He first worked in Grenoble during his post-doctoral period and then in the Villeneuve-d'Ascq laboratory which he joined in 1998 as a visiting scientist. Promoted to a research engineer two years later, he decided to settle in France despite several offers in Brazil. “But I still do my best to maintain scientific cooperation with my native country,” he concludes.


Emmanuel Thévenon




Notes :

1. Laboratoire de cristallochimie et physico-chimie du solide (Laboratory of Crystal Chemistry and Solids Physical Chemistry, CNRS / Université Lille-I / Université Valenciennes joint lab).
2. Laboratoire d'électrochimie et de physico-chimie des matériaux et des interfaces (LEPMI, Laboratory of Electrochemistry and Physical Chemistry of Materials and Interfaces. CNRS / INP Grenoble / Université Grenoble-I joint lab).

Contacts :

César Steil
LCPS, Villeneuve-d'Ascq.


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