High temperature in-situ phase stability of sputtered TiAl x N coatings

Document Type

Journal Article


Elsevier Ltd


School of Engineering


Originally published as: Patel, S. B., Mohammadpour, E., Mondinos, N., Zhao, X., Veder, J. -., Zhou, Z. -., . . . Jiang, Z. -. (2019). High temperature in-situ phase stability of sputtered TiAl x N coatings. Journal of Alloys and Compounds, , 507-514. Original article available here


The temperature dependence of phase composition and lattice parameters, for TiAl x N thin film coating, are experimentally investigated by in-situ synchrotron radiation X-ray diffraction (SR-XRD), at temperatures between 25 °C and 700 °C. Mechanical properties, such as: Young's modulus (E), hardness (H) and plastic deformation index (PDI) – were experimentally determined by nanoindentation, at 25 °C. Crystalline structural analysis, of SR-XRD results, indicates the major phases are TiN and AlN; with Ti 2 O and TiO 2 phases also present above 600 °C. The lattice constants increased with an increase in temperature. Atomic and phase compositions, at 25 °C, were also verified by X-ray photoelectron spectroscopy (XPS). Field emission scanning electron microscopy (FESEM) images display an increase in surface roughness and reduction in grain size, with increasing Aluminium percentage (Al%). Nanoindentation analysis showed a maximum hardness of 25.1 ± 1.5 GPa (sample containing 12% Al), which was subsequently reduced upon addition of more Aluminium. Finite element modelling (FEM), including von Mises stress distribution, indicates lower mechanical integrity, for samples with high Al% content. © 2019