Experiments were conducted to study the effect of liquid and gas phases of water as the oxidizer combusting with both micron- and nano-sized aluminum particles. Combustion of aluminum with steam was achieved using a Bunsen-type dust cloud apparatus. During the experiment, the aluminum particles, ∼5-8 microns in diameter, were entrained in a high-velocity steam flow while the aerosol velocity is regulated by an ejector system to maintain a stable flame at the end of the contoured nozzle. AI/steam/N2 flames were obtained for various equivalence ratios at atmospheric pressure. The flame luminosity was less than that of aluminum/air mixtures due to the reduction in flame temperature. Linear and massburning rates of mixtures of nanoaluminum (38 nm) and liquid water as a function of pressure and mixture composition at room temperature were measured using a constant volume optical pressure vessel. At the highest pressure studied (4.3 M Pa), the linear burning rate was found to be 8.6β0.4 cm/s corresponding to a mass-burning rate of 6.1 g/cm 2-s. The pressure exponent at room temperature was 0.47, which was independent of the overall mixture equivalence ratio for the cases considered.