Cerium-based conversion coatings on Al(18)B(4)O(33)w/6061Al composite surface were obtained by immersing the composite into a solution containing various concentrations of CeCl3. Results indicate that the susceptibility to pitting for the conversion-coated composites was much lower than that of the untreated composite, and the corrosion resistance of the coated composites was improved markedly; moreover, the concentration of CeCl3 in the cerium solution affects significantly the corrosion behaviors of the coated composites. The coating obtained from a solution containing 7.5 g CeCl3 into 1000 ml produced better corrosion resistance on the composite due to the surface being almost covered by conversion coating. EDX and XPS experimental results indicated that the coatings were made up of oxygen, cerium, and aluminum. (c) 2007 Elsevier B.V. All rights reserved.