Corrosion behavior of Al-Zn/Al2O3 and Al-Zn-X/Al2O3 (X = Cu, Mn) composites synthesized by mechanical-thermal treatment

The development of ceramic particulate reinforced aluminum metal matrix composites (MMCs) has resulted in advanced engineering materials for potential use in structural applications in automobile and marine industries. In the present work we have analyzed the corrosion behavior of Al-Zn-Al2O3 MMCs with minor alloying additions of Cu and Mn. The composites have been prepared via reaction sintering of partially reacted oxide mixtures derived from a high-energy ball milling process. The influence of the high-energy ball milling on the corrosion behavior of composites in a 3.5 wt% NaCl solution has been investigated through electrochemical experiments. The results of the corrosion tests, evaluated using the potentiodynamic method in the NaCl solution, indicate that the corrosion of the investigated composite materials depends on the weight fraction of the reinforcing particles. The polarization curves show that the milling procedure improves the corrosion resistance of the composites in the passive condition. This is illustrated by the corrosion potential, which becomes more and more noble with milling. (c) 2007 Elsevier B.V. All rights reserved.