Abstrait

Study of some characteristics describing the oxidation of a {m,m�?�?�?�?�?�?�?�?}-based {30Cr, 1C, 15Ta} containing alloy during heating up to high temperature and the oxide scales behavior during post-{isothermal stage} cooling. part 1: {m, m�?�?�?�?�?�?�?�?}={Ni, Co}

Ga�?�?�?�?�?�?�?«l Pierson, Kevin Duretz, Thierry Schweitzer, Elodie Conrath, Patrice Berthod

An alloy based on nickel and cobalt in equal parts, rich in chromium and containing a dense TaC network in itsmicrostructure was tested in oxidation at high temperature in dry synthetic air. The thermogravimetry tests were performed at 1000, 1100 and 1200°C during 40 hours. The mass gain files were plotted versus temperature and exploited to specify the oxidation start during heating and spallation start during cooling temperatures as well as the successive parts of mass gain achieved during heating and during the isothermal stage. The three mass gain kinetics were globally parabolic and the oxidation rateswere characteristic of a chromia-forming behaviour. The oxidation start temperature at heating was seemingly the same for the three tests. The higher the temperature the higher the heating mass gains and the isothermal mass gain, and also the higher the temperature of spallation start at cooling. The mass gain obtained at the end of heating represents about 5% of the total mass gain.