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One of the main problems encountered during the fabrication of Al-matrix composites reinforced with SiC particulates is the possible formation of Al{sub 4}C{sub 3}. This compound is very detrimental for the mechanical properties of the composites owing to its hydrophilic character. Moreover the occurrence of the reaction leads to Si rejection in the matrix thus changing also its properties. One way to prevent the formation of Al{sub 4}C{sub 3} during fabrication or subsequent recycling treatment is to use Al-Si alloys as the matrix. However the amount of Si needed to prevent the reaction is temperature dependent and alloys containing 7 to 9 wt% Si can thus be used up to about 750--800 C without Al{sub 4}C{sub 3} formation. The other way which can be employed particularly with wrought Al-alloys is to coat the particulates. Various oxide coatings produced either by a sol-gel or a day mixing technique were tested recently and it was shown that the rate of degradation was significantly decreased as a consequence of the formation of more stable oxides. TiO{sub 2} coating was found particularly efficient in Mg containing Al-alloys owing to the formation of MgO or MgAl{sub 2}O{sub 4}. The aim of this study is to investigate the influence of a complex tin and antimony oxide coating on the rate of degradation of the particles in liquid aluminum. Al-Mg alloys were also used in this work for comparison with previous studies. The presence of Mg allows to follow the reaction rate by making the alloy age hardenable when some Si is rejected as a consequence of Al{sub 4}C{sub 3} formation. However, this technique is only efficient during the first stages of the …