An experimental program to determine the feasibility of thermally spraying aluminum on a lead substrate was initiated in support of the accelerator production of tritium (APT) Project for the U.S. Department of Energy. The program consisted of two distinct parts: (1) the characterization of the thermally sprayed coatings,including microhardness testing, effects of heating, and microstructure and porosity determinations, and (2) effects of mercury doping and heat treatments on the thermally sprayed composite. The project determined that aluminum could successfully be thermally sprayed onto the lead. The coatings had a dense microstructure, with a Vicker's Pyramid Hardness (VPH) of about 60, and a maximum porosity (found in strips on the samples) of 12%. Published by Elsevier Science Inc.