The caustic leaching kinetics of the rapidly quenched Ni-Al alloys has been studied by measuring the evolution of H-2 during the leaching process. The effects of various parameters, such as the composition and the particle size of the Ni-Al alloys, the concentration of the NaOH aqueous solution, and the temperature have been systematically investigated. It is found that the leaching process of the rapidly quenched Ni-Al alloys can be well fitted by a reaction-controlled shrinking core model, which is attributed to the uniform microstructure of the alloys prepared by the rapid quenching technique. (C) 2003 Elsevier B.V. All rights reserved.