Differential sputtering and the formation of repeating fragments in ToF-SIMS spectra of light metal alloy surfaces

Authors

  • Chuong L. Nguyen,

    Corresponding author
    1. Materials Accelerator, The University of Auckland, Auckland, New Zealand
    • Light Metals Research Centre, School of Chemical Sciences, The University of Auckland, Auckland, New Zealand
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  • James B. Metson

    1. Light Metals Research Centre, School of Chemical Sciences, The University of Auckland, Auckland, New Zealand
    2. MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, Wellington, New Zealand
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Chuong Nguyen, Light Metals Research Centre, School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. E-mail: c.nguyen@auckland.ac.nz

Abstract

Time of flight secondary ion mass spectrometry (ToF-SIMS) spectra of aluminium hydroxide powders and thin films suggest that fragments of largely intact hydroxide layers are cleaved from the surface during ion bombardment. This leads to the presence of large repeating clusters of aluminium oxide dominated fragments up to 3000 Da in the SIMS spectra. The more intense repeating fragments of aluminium species appear to enhance the sputter rate on Al2O3. In the case of oxide films on the surface of aluminium alloy with 13 wt.% Si, there were no detectable higher mass repeating fragments for silicon species. The difference is linked both to the limited observations of these very large fragments in the absence of a layered crystal structure and the initially higher removal rate of aluminium species compared with silicon species on the surface of this alloy. This latter observation, confirmed by SIMS imaging during profiling, is at odds with typical observations reported in the literature. Copyright © 2012 John Wiley & Sons, Ltd.

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