IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Iron L-shell chemical effects in iron nitride films
Autor/es:
ANA BERTOL; SAULO JACOBSEN; PABLO PÉREZ; JORGE TRINCAVELLI; GUSTAVO CASTELLANO; RUTH HINRICHS; MARCOS VASCONCELLOS
Lugar:
Gramado - Rio Grande do Sul
Reunión:
Congreso; 13th International Conference on Particle-Induced X-ray Emission; 2013
Institución organizadora:
Laboratório de Implantação Iónica, Instituo de Física, Universidade Federal do Rio Grande do Sul, Sociedade Brasileira de Física, International Atomic Energy Agency
Resumen:
Iron nitride phases have been studied for a long time, due to their application in magnetic recording and because of their wear reducing properties when used as protective surface coatings. These phases can be obtained by various methods. It has been shown that reactive magnetron sputtering can produce phases encompassing the whole composition range in the phase diagram, even disclosing new phases and structures [1]. In this work two iron nitride films were obtained with different deposition atmospheres (Fe_x N_y 1 with 80 vol% N_2: 20 vol% Ar and Fe_x N_y 2 with 40 vol% N : 60 vol% Ar). The films were deposited on carbon planchets with nominal thickness of 10 nm using the reactive magnetron sputtering process in a ultra-high vacuum equipment. The phase composition of the films was characterized using GIXRD and Mössbauer spectroscopy, and their elemental composition was determined with Rutherford backscattering spectrometry (RBS) in the High Voltage Engineering 3 MV Tandetron of the Laboratório de Implantação Iônica, IF-UFRGS, Brasil. The spectra of the Fe-L-lines from the two films and a bulk iron standard were acquired using an electron probe microanalyser (JEOLJXA8230 in the Laboratorio de Microscopía Electrónica y Análisis por Rayos X of the Univ. Nacional de Córdoba, Argentina) equipped with a wavelength dispersive spectrometer (WDS) with a synthetic crystal (LDE1) with 2d≈ 60 Å. The beam energy was kept at 5 keV. The spectra were processed with the software “POEMA” [2], considering the necessary adjustments of the bremsstrahlung, the characteristic line intensities, the peak shape, and the detector efficiency. The latter factor was obtained calibrating the WDS spectrometer efficiency against the EDS efficiency, measuring reference spectra simultaneously in the EPMAwith both spectrometers [3]. The comparison of the spectra showed that the position of the La_1,2 line that is due to transitions of the outer M shell was shifted (Figure 1) and that the relative intensities of the La/Lb -lines, were affected by the chemical environment. We propose the use of the chemical effects as an additional phase recognition method, which can be used as a depth sensitive technique in cross sections of thicker films, as those used in wear coatings obtained by conventional glow discharge plasma nitriding.