High-temperature oxidation resistance behavior of porous Ni-16Cr-9Al materials
The oxidation behavior of porous Ni-16Cr-9Al alloys at 800 and 1 000 8C was studied using the isothermal temperature oxidation method. The differences in surface morphology, phase and pore structure between oxidized and non-oxidized materials were characterized by means of scanning electron microscopy, X-ray diffraction analysis and mercury intrusion porosimetry. The results revealed that the oxidation rate of the samples which were oxidized for 420 h at 800 8C was 0.012 %2 h-1 and the oxidation products were Al2O3 and Cr2O3. The oxidation rate of the samples which were oxidized for 390 h at 1 000 8C was 0.415 %2 h-1 and the oxidation products were Al2O3, Cr2O3 and Ni(Cr, Al)2O4. All the oxidation kinetics curves obeyed the parabolic law, exhibiting excellent high temperature oxidation resistance.