Search results for "Nickel aluminide"
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High temperature reactivity of nickel aluminide diffusion coatings
2008
Abstract The high-temperature oxidation behaviour of nickel aluminides has been studied at 900 °C in air under atmospheric pressure. Yttria doped and undoped specimens of nickel were aluminised and then oxidised for 100 h under isothermal and cycling conditions. The results showed that when yttria is added by metal-organic chemical vapour deposition technique prior to the aluminisation process, it increased the oxidation rate of aluminised nickel, but improved the oxide scale adherence under cyclic conditions. The effects of yttria on the scale morphology, oxidation behaviour and scale spallation tendency are discussed based on the experimental results, using X-ray diffraction (XRD), scanni…
Elaboration of Nickel Aluminide Diffusion Coatings: Application to Oxidation Resistance
2008
Aluminide diffusion coatings are widely used in aeronautic domain. Nickel based superalloys present good mechanical properties and creep resistance at high temperature but their corrosion resistance is somewhat poor. In order to enhance their lifetime at high temperature, aluminide coatings can be applied on alloy surface. Aluminium present on material surface can form, at high temperature, alumina scale which is a protective oxide scale. In the present study, nickel aluminide coatings were carried out by aluminisation in a single step pack cementation process on nickel based superalloys 600 and AM1. Ni-Al intermetallic was obtained in each case. Oxidation tests were carried out at 900°C in…