Thermally stimulated crystalline phase transformations in metastable Fe–Cr alloy films prepared by pulsed laser deposition

Abstract

Thermally induced crystalline phase formation of metastable Fe–Cr alloy films with different Cr-content (34.5, 43.5 and 48.5 at.% Cr) and thickness of 100 nm prepared by cross-beam pulsed laser deposition was examined by wide angle X-ray scattering. Therefore the annealing temperature was increased stepwise up to 1100 °C, the duration of the treatment per step was 90 min. Through a number of intermediate metastable crystalline phases, above 550 °C the phase composition did not change until the onset of reaction with Si/SiO 2 substrate at ∼900 °C. Equilibrium σ-FeCr is formed in all samples. In addition, body-centered cubic (b.c.c.) and tetragonally distorted b.c.c. Fe–Cr phases are formed in a film with nearly equiatomic composition. Reactions with substrate result in formation of Fe- and Cr-silicides.