Comparison of nitrogen ion beam and plasma immersion implantation in Al5052 alloy

Experiments comparing nitrogen ion implantations in Al5052 by beam and plasma immersion were carried out. Beam implantation (BI) was carried out using a 100 keV, high current beam implanter while the plasma immersion ion implantation (PIII) was obtained using a glow discharge plasma source coupled to a pulsed high voltage supply. A nitrogen BI dose of 5 × 1017 cm−2 at 100 keV was attained with near Gaussian implantation profile while the PIII was performed until we reached similar doses with a maximum energy of 15 keV. Implantation profiles were obtained by Auger electron spectroscopy (AES). X-ray diffraction (XRD) indicated the formation of AlN in both cases but it was more clearly demonstrated by high resolution AES. For BI treatment, a buried AlN layer was achieved while for PIII, a layer of AlNxOy close to the surface was seen. Due to the high temperature reached in the PIII processing (400 °C), a softening of the Al5052 bulk resulted while for BI processed samples with <200 °C an increase in hardness was observed.