Influence of volume fraction and particles size on the corrosion resistance of aluminium composite with ceramic particles
Katarzyna Łuczak, Piotr Liberski, Józef Śleziona Politechnika Śląska, Katedra Technologii Stopów Metali i Kompozytów, ul. Krasińskiego 8, 40-019 Katowice
Annals 3 No. 6, 2003 pages 75-78
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abstract This paper presents the comparative results of corrosion resistance of the aluminium matrix composite with ceramic particles. The research was carried on the AK 12 aluminium matrix reinforced with Al2O3 and SiC particles. They were compared with the aluminium matrix. This research was conducted in environment containing Cl− ions which the aluminium alloys are not resistant to. The comparative corrosion test in neutral salt spray (NNS 5% solution NaCl) by laboratory investigation was made. Mass changes of specimens were determined in fixed period of time exposition (Fig. 1) and corrosion rate was calculated (Fig. 2). It has been noticed the addition of ceramic particles influences the decrease of the corrosion resistance. Also electrochemical parametres of corrosion process in potentiostatic method in 5% water solution were specified. It has been noted that the addition of ceramic particles into aluminium matrix influences the polarisation curves (Fig. 3) that the tested materials are susceptible to pitting corrosion and the additon of ceramic particles influences the increase of intensity of pitting corrosion. Presented results indicate on worse corrosion resistance of ceramic particles reinforced aluminium matrix composite, in comparison with aluminium matrix, and their resistance depends on particles kind, size and volume fraction. Moreover, introducing to AK12 aluminium matrix the SiC ceramic reinforcing particles gives better resistance to interaction of aggressive environment that AK12 aluminium matrix reinforced with Al2O3 particles. Corrosion resistance of these composites decreases with increase of volume fraction and diameter particles. Key words: corrosion resistance, aluminium alloys, polarisation curves