Investigation of phase transition employing strain mapping in TT- and T-Nb2O5 obtained by HRTEM micrographs

[Display omitted] •Synthesis of TT-, T- and H- phases of Nb2O5 by controlled polymeric method.•Unprecedented Nb2O5 strain mapping by HRTEM micrographs, using the geometric phase analysis (GPA).•High strain values in the boundaries of the particles and along the b-c axis due to disordered polyhedral.•Increased crystallite size causes changes in average strain and the phase segregation between TT- and T- phases. This work aimed to study the crystalline structure of TT-,T-phases of Nb2O5 nanoparticles through XRD, Rietveld refinement, and HRTEM, using geometric phase analysis (GPA). The results show the presence of distorted NbO6 and NbO7 polyhedral, producing strain effects, mainly in the plane boundaries and along the b-c plane. XRD and HRTEM analyses show the TT→T transition at 700 °C, with increased particle size and increased strain in the boundaries between nanoparticles. The sample calcinated at 700 °C presents segregation of the TT-(001), (100), and T-(130) planes, where the strain effect is more relevant along the [100] zone axis and between phases.