Emission acoustique couplée à la thermogravimétrie. Application à la corrosion par métal dusting.

National audienceContents:1-Catastrophic corrosion of Fe-based alloys in reducing environment with high carbon activity (ac > 1) → 400°C - 700°C.2-Experimental device** High-temperature corrosion** Innovative solution: TGA + EA in situ** Waveguide test at room temperature** Test at high temperature: Zirconium alloy oxidation** Rate of mass gain as a function of time** Bursts average frequency variation as a function of time blank test (▲) Zircaloy-4 oxidation air test (●)** Rate of mass gain and burst amplitude as a function of time3-Metal dusting** Metal dusting of pre-oxidized iron at 650°C** Rate of mass gain of pre-oxidized iron at 650°C** Burst amplitude as a function of time** Metal dusting of iron at 650 °C** Mechanism (Metal dusting of pre-oxidized iron)4-ConclusionThe TGA / EA Coupling is efficient to deepen knowledge in alloys corrosion at high temperature•Simultaneous acquisition in situ of the sample mass change and of the acoustic signals•Validation of the waveguide at ambient temperature and high temperature•Allocation of bursts of EA emissive phenomena to cracks during oxidation or cooling: advantage over post mortem observations samples5-Developments** High temperature (>1000°C) in the corrosive atmosphere (metal alloys, cermet) → Assignment of EA signals to cracks** Cycling test