The pitting behavior of Al-3103 implanted with molybdenum X. Zhang a, * , S. Lo Russo a , S. Zandolin a , A. Miotello b , E. Cattaruzza c , P.L. Bonora d , L. Benedetti d a INFM, Dipartimento di Fisica, Universit  a di Padova, Via Marzolo 8, 35131 Padova, Italy b INFM, Dipartimento di Fisica, Universit  a di Trento, Via Sommarive 14, I-38050 Povo, Italy c INFM, Dipartimento di Chimica Fisica, Universit  a di Venezia, Dorsoduro 2137, I-30123 Venezia, Italy d Dipartimento di Ingegneria dei Materiali, Universit  a di Trento, Via Mesiano 77, I-38050 Mesiano, Italy Received 20 January 2000; accepted 9 May 2000 Abstract The pitting corrosion of Al-3103 (Al±Mn alloy) implanted with molybdenum was investi- gated in solutions containing 0.1 M NaCl using potentiodynamic polarization tests. The Mo ion implantation in Al-3103 was performed with ion energies from 50 to 100 keV at doses ranging from 5  10 16 to 2  10 17 ions/cm 2 . The Mo depth pro®les were measured by Ruth- erford backscattering spectrometry. Polarization tests were performed in the presence and absence of a bicarbonate (HCO  3 )/carbonate (CO 2 3 ) buer. Compared to the unimplanted ones, the implanted samples showed an increase of corrosion potentials from 170 to 240 mV in the unbuered solution and an increase of pitting potentials from 90 to 160 mV in the buered solution. The surface chemical states and corrosion morphology of the samples were analyzed by X-ray photoelectron spectroscopy and scanning electron microscopy, respectively. Ó 2000 Elsevier Science Ltd. All rights reserved. Keywords: Aluminum alloy; Ion implantation; Passivation; Pitting 1. Introduction Materials of aluminum alloys play a very important role in modern industry. The Al±Mn alloy (Al-3103), due to its high heat conductivity, mechanical strength and www.elsevier.com/locate/corsci Corrosion Science 43 (2001) 85±97 * Corresponding author. Tel.: +39-49-827-7020; fax: +39-49-827-7003. E-mail address: zhang@padova.infm.it (X. Zhang). 0010-938X/00/$ - see front matter Ó 2000 Elsevier Science Ltd. All rights reserved. PII:S0010-938X(00)00058-5