Purushotham, N.Santhy, K.Suresh Babu, P.Govindarajan, G.Rajasekaran, R.2026-02-042023Journal of Thermal Spray Technology, 2023, 32, 7, pp. 2091-210310599630https://doi.org/10.1007/s11666-023-01627-whttps://idr.nitk.ac.in/handle/123456789/21701In situ high-temperature x-ray diffraction (HT-XRD) was used in the present study to assess the coefficient of thermal expansion and recrystallization of Ni-5 wt.%Al coatings. Atmospheric plasma spray (APS) and detonation spray (DSC) techniques were used to deposit Ni-5 wt.%Al coatings on IN718 substrates. The coatings were examined using HT-XRD at ambient conditions (25 °C) up to high temperatures (1150 °C) under a vacuum pressure of around 10−4 mbar. Coefficients of thermal expansion (CTE), crystallite size (D) and lattice strain (ε) were determined by the Scherer and Williamson-Hall (W-H) method with a uniform strain model (UDM) using x-ray peak profile analysis (XPPA). The microstructure of the Ni-5 wt.%Al coatings was analyzed by field emission scanning electron microscopy (FESEM). No phase changes were observed in either coating, as the Ni-5 wt.%Al coatings consisted mainly of γ-Ni crystals with a face-centered cube (FCC) phase in both coating techniques. Lattice parameters as a function of temperature were used to calculate linear thermal expansion coefficients. The linear thermal expansion of Ni-5 wt.%Al coatings deposited by both thermal spray methods was discussed on the basis of process-induced microstructures. © 2023, ASM International.Aluminum coatingsAtmospheric temperatureCrystallite sizeDetonationField emission microscopesMicrostructureNickel compoundsPlasma jetsPlasma sprayingScanning electron microscopySprayed coatingsX ray diffractionAl coatingsAtmospheric plasma sprayingAtmospheric plasma-sprayingDetonation sprayDetonation spray coatingHigh-temperature XRDIn situ high-temperature XRDLattice strainSpray coatingWilliamson-HallThermal expansion