Abstract
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MAX phases display a unique combination of characteristics of both metals and ceramics, and unusual mechanical, electrical and thermal properties. In this chapter, the oxidation characteristics of Ti3 AlC2, Ti3 SiC2 and Ti2 AlC over the temperature range 500-1400 oC were studied by synchrotron radiation diffraction, neutron diffraction, secondary-ion mass spectrometry (SIMS) and nuclear magnetic resonance (NMR) experiments, which provided elemental and phase compositional depth profi les over this range as well as evidence of glassy phase formation. Evidence for the outward diffusion of Al or Si during oxidation was shown for the fi rst time by the complementary SIMS and NMR results, suggesting amorphous Al or Si at low temperature oxidation, which is vital for strong adherent oxide scales during oxidation. During oxidation, anatase formed at 500 oC, which transformed to rutile at 600 oC and was completed by 900 oC. The crystalline phase α -Al2 O3 was detected at 900 oC in Ti3 AlC2 or Ti2 AlC. Tridymite and cristobalite were detected at 1000 and 1350 oC respectively in Ti3 SiC2. © 2012 Woodhead Publishing Limited.