27Al and 7Li spin-echo and spin-echo double resonance NMR applications to the study of lithium depletion and surface oxidation in Al-Li alloy

The physical properties and the near-surface microstructures of Al-Li alloys are known to be affected by thermo-mechanical processes during alloy manufacture. The research reported here explored Al-27 and Li-7 spin-echo and spin-echo double resonance NMR to follow the structural changes that accompany lithium depletion and oxidation processes at the alloy surface. The NMR analysis generally agrees with conclusions reached previously using other analytical methods. The major oxide compound generated is Li2CO3 and the minor oxide compound is LiAlO2, which is formed at higher temperatures. LiAlO2 is shown to be formed in spatially confined clusters on the surface of the Li-depleted, Al-rich near-surface layer. Copyright (C) 2001 John Wiley Sons, Ltd.