Pierre Raynaud

Suivi cinétique de la relaxation des contraintes de croissance au cours de l'oxydation d'un alliage FeCrAl☆

The oxidation behaviour of FeCrAl alloy in O2 was studied in the temperature range 800–1200°C for two types of sample: platelets and wires. In both cases the oxidation rate is controlled by a diffusion process. However, the induced growth stresses and their relaxation are very sensitive to the geometry of the oxidized sample. They have been evaluated as a function of time and temperature by following the resulting differences observed in the rate constants.

Equipment for studying hot corrosion processes in dynamic gas mixtures containing water vapour

Abstract A Setaram unit including a symmetric oven and a MTB 10 8 microbalance was chosen as a base equipment in order to reduce the impulse variations frequently occurring in dynamic regimes. The thermobalance and its surroundings were thoroughly thermostated owing to water vapour. To pull up and let down the sample quickly without damage for the torsion strip, a telehandling airtight apparatus with visual control has been worked out, allowing to make optional the connection between the suspension chain and the microbalance beam. The equipment here described has been conceived for hot corrosion kinetic studies (round 1000°C) concerning low weight samples (10–100mg) in such gaseous flows as X/H2O containing air, oxygen and hydrogen in the presence of water vapour (1–75 %).

Relaxation of the Mechanical Stresses Developed Through Oxide Scales During Oxidation of Metals

The oxidation behaviour of a FeCrAl alloy has been studied in various atmospheres containing water vapour (O2/H2O mixtures) in the temperature range 800–1200°C. The growth stresses developed through the oxide scale and their relaxation have been followed by comparing kinetics obtained from planar and cylindrical samples.