Article

Thermophysical Properties of Materials

2022. V. 60. № 3. P. 345–352

Chandio AliDad, Shaikh AsifAhmed, Ahmed Haseeb

Isothermal oxidation studies of

$\beta\rm NiAl$ coatings for aeroengine applications

Annotation

Nickel aluminide

$(\beta\rm NiAl)$ coatings were prepared by

$in~situ$ aluminising technique onto CMSX-

$4$ superalloy substrates and isothermally oxidised at

$1150^{\circ}$ C for

$100$ h. The factors influencing the spallation resistance of

$\beta\rm NiAl$ coatings were examined. The thermally grown oxide formed during oxidation was found to be multiphase

$(\rm TiO_2{,}~\rm Ni_2\rm AlO_4{,}$ and

$\theta$ -

$\rm Al_2O_3)$ along with pure

$\alpha$ -

$\rm AL_2\rm O_3$ . Coatings and substrate underwent massive interdiffusion resulting in

$(\rm i)$ segregation of alloy-precipitates at thermally grown oxide and coating interface,

$(\rm ii)$ sulphur migrated from substrate was present in such precipitates and

$(\rm iii)~\rm Ni$ influx and

$\rm Al$ depletion rendering

$\beta\rm NiAl \to \gamma'$ -

$\rm Ni_3\rm Al$ transformation. Moreover, the degree of spallation and thermally grown oxide residual stresses increased with the oxidation time.

Article reference:
Chandio AliDad, Shaikh AsifAhmed, Ahmed Haseeb Isothermal oxidation studies of

$\beta\rm NiAl$ coatings for aeroengine applications, High Temp., 2022. V. 60. № 3. P. 345

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