Characteristics of corroded surface of extruded aluminum borate whisker reinforced pure aluminum composite

The changes of the surface morphology of an extruded composite of Al₁₈B₄O₃₃ w/ pure Al during the early stages of corrosion by 3.5 % NaCl solution were observed by atomic force microscopy. The features of corrosion of the composite samples with different normal angles to the extrusion orientation in 3.5% NaCl solution were studied. The results indicated that corrosion occurred preferentially at the interface between whisker and matrix. Pitting occurred frequently at the end of whisker firstly and propagated along the interface between whisker and matrix. The number and size of pits on the surfaces of the extruded Al₁₈B₄O₃₃ w/ pure Al composite samples are different due to the sample surfaces with various angles to the extrusion orientation of the bulk composite.