Dr Irina Pozdnyakova

Nationality: 
United States
Scientific Field: 
Materials and Energy sciences
Period: 
January, 2017 to January, 2018
From: 
IMERYS
In residence: 
Cemhti
Project title: 
Study of the kinetics of corrosion of refractory ceramics by liquid slags

The knowledge of the reaction kinetics of corrosion of refractory ceramics used in industrial processes at high temperature has become essential for modeling their damage and for optimizing either the materials of the processes. All phase transformations occurring during the processes are generally known but the reaction speeds have been rarely studied in particular because of the experimental difficulties for in situ observations of a heterogeneous reactive system such as a molten slag in contact with a refractory ceramic. A PhD thesis, currently underway at the CEMHTI, showed the validity of a proposed approach based on X-ray diffraction analysis at high temperature (up to 1650 °C) allowing to study phase transformations during the corrosion of a ceramics with a liquid slag. Due to high reaction speeds, it is not currently possible to obtain complete and accurate information on the structural evolution of the system. It is therefore necessary to use synchrotron techniques to go further. This project which will be in continuation of the thesis and will 1) improve the quality of the analysis and 2) enable to study more complex systems (chemically). The reaction kinetics is also linked to the impregnation rate of the ceramic and thus to the viscosity of the slag. In parallel of the kinetic studies, it is then important to study the evolution of the high-temperature viscosity as a function of temperature. Despite their importance, there is very little data in this area. The determination of thermophysical properties of the slags will be an important step forward. These kinetic aspects and viscosity are the two main objectives of this project in which we will first consider simple compositions to understand the phenomena and then increase the complexity of the slag in order to finally approach closest as possible the industrial compositions.

Host Scientist: 
Jacques Poirier