Metal-matrix composites corrosion testing

Metal-matrix composites are thought to corrode by a crevice corrosion mechanism with the crevice forming at the fibre/matrix interface (Cosgrave and Hinton 1991). They have studied the corrosion behaviour of an Al alloy 6061/boron metal-matrix composite in 0.1 M NaCl solution. As shown in fig. 11, the presence of lOOOppm CeCls in the test solution, significantly reduced the corrosion rate of the composite, particularly at long immersion times. After testing with CeCls present, a thick opaque yellow film of hydrated Ce oxide was observed on the surface of the composite. Cosgrave and Hinton concluded that the presence of this film was responsible for the corrosion protection, and that the... 

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