Benzotriazole (BTAH) was used for the first time to inhibit the corrosion of Al-B4C composites in a NaCl solution. Its corrosion inhibition effect was systematically investigated as a function of BTAH concentrations, volume fractions of B4C particles and immersion time by using potentiodynamic polarization, electrochemical impedance and infrared reflection adsorption spectroscopy techniques. It was found that BTAH is a good corrosion inhibitor for the Al-B4C MMCs in a 3.5 g L-1 NaCl solution, and its inhibition efficiency increased with increasing BTAH concentration. For the same BTAH concentration and immersion time, higher B4C volume fraction leads to higher corrosion inhibition efficiency. The inhibition efficiency of benzotriazole was also influenced by the immersion time: the inhibition efficiency increases with the immersion time in the first 18 h. However, prolonging the immersion time leads to a decrease in the inhibition efficiency. As the BTAH was an inhibitor with a cathodic character and it inhibited corrosion by physically adsorbing on B4C particles at the composite surface, it obeyed the Freundlich adsorption isotherm. (C) 2013 Elsevier B.V. All rights reserved.