Enhanced sulphidation/oxidation resistance of Ti–45Al–8Nb alloy by nanostructured CrAlYN/CrN coatings at 750 °C

Authors

  • T. Dudziak,

    Corresponding author
    1. Advanced Materials Research Institute, School of Computing, Engineering and Information Sciences, Northumbria University, Newcastle-upon-Tyne, UK
    • Advanced Materials Research Institute, School of Computing, Engineering and Information Sciences, Northumbria University, Newcastle upon Tyne, NE1 8ST (UK)

      E-mail: t.dudziak@cranfield.ac.uk

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    • Currently Research Fellow at Cranfield University, Bedfordshire, MK43 0AL (UK).
  • H. L. Du,

    1. Advanced Materials Research Institute, School of Computing, Engineering and Information Sciences, Northumbria University, Newcastle-upon-Tyne, UK
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  • P. K. Datta,

    1. Advanced Materials Research Institute, School of Computing, Engineering and Information Sciences, Northumbria University, Newcastle-upon-Tyne, UK
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  • A. P. Ehiasarian,

    1. Nanotechnology Centre for PVD Research, Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield, UK
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  • C. Reinhard,

    1. Nanotechnology Centre for PVD Research, Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield, UK
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  • P. Eh. Hovsepian

    1. Nanotechnology Centre for PVD Research, Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield, UK
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Abstract

This paper discusses the sulphidation/oxidation protection offered by multilayer CrAlYN/CrN coatings etched by Cr, CrAl and Y ions, deposited by a combined high power impulse magnetron sputtering (HIPIMS)/unbalanced magnetron sputtering (UBM) technique on a Ti–45Al–8Nb alloy (at%). The test was performed at 750 °C in an environment of H2/H2S/H2O yielding low oxygen (10−18 Pa) and high sulphur (10−1 Pa) partial pressures for up to 1000 h. The results show that all the exposed materials underwent uneven degradation; some places developed a thin protective oxide scale (Al,Cr)2O3 with a tiny sulphur content, whilst others developed a porous non-protective TiO2 + Al2O3 scale as well with a tiny sulphur content.

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