IFIR   05409
INSTITUTO DE FISICA DE ROSARIO
Unidad Ejecutora - UE
artículos
Título:
Austenite modification of AISI 316L SS by pulsed nitrogen ion beams generated in Dense Plasma Focus discharges
Autor/es:
FEUGEAS J., RICO L., NOSEI L., GÓMEZ B., BEMPORAD E., LESAGE J. FERRÓN J.
Revista:
SURFACE AND COATINGS TECHNOLOGY
Editorial:
ELSEVIER SCIENCE SA
Referencias:
Año: 2009 vol. 204 p. 1193 - 1199
ISSN:
0257-8972
Resumen:
We present the results of surface modification of AISI 316L stainless steel by surface irradiation with high energy, pulsed nitrogen ion beams generated with 0.8 kJ Dense Plasma Focus. The surface characterization was done using GAXRD, Auger electrons spectroscopy, TEM and optical microscopy. After the irradiation, we found a modification of a 1 μm thick surface layer, on which a gradual lattice expansion of the austenite was observed with the number of irradiation pulses, i.e. with the total nitrogen ion fluence. In addition, on the _40 nm close to the surface layer, a disordered lattice structure had been observed through TEM analysis. Those results can be explained in terms of the extreme thermal effect induced on the surface through the fast high energy release during the pulsed ion interaction with the steel surface, followed by an also rapid cooling down process which limits the nitrogen diffusion to the bulk. This lattice gradual expansion of the austenite is different from the results observed on glow discharges ion nitriding processes, in which an abrupt expan- sion of the lattice parameters of the austenite are produced starting at certain time during the process (explained by Mändl et al., J. Appl. Phys. 91 (2002) 9737), conducting to a phase known as expanded austenite.