Abstract
In this work structural changes of NiCrAl doped by Fe and Si powder after annealing at high temperatures are observed. The material under study was annealed at 800, 1000 and 1200 °C in an air atmosphere for 24 h and the structures obtained were compared with the as-received state. Phase analyses were performed based on X-ray diffraction measurements. The lattice parameters of current phases were measured and quantitative analyses were carried out by the Rietveld refinement from the XRD patterns measured. The character and size of powder particles as well as their chemical composition were studied by SEM equipped with EDX. After exposure at 800 °C for 24 h, the major part of whole material still in a primer solid solution formed, unlike after exposure at 1200 °C whole volume of material transformed into oxides. The presence of different oxides was observed after heating at different temperatures with dominance of NiO. Change of lattice parameters of present phases was observed, what can be concluded as a dissolution effect.

Key words
high-temperature oxidation, NiCrAl powder, phase transformation

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