The processing variables which lead to the rough, convoluted surface topologies of platinum modified aluminide coatings were studied. Platinum deposition techniques such as electroplating, ion plating, and sputtering were examined as were postplating diffusion treatments and aluminizing processes. It was found that while the initial Pt surface could be varied by the deposition process and procedures selected, the principal factor influencing surface topology was Pt substrate (IN-738) interdiffusion. Subsequent aluminizing processing had a much smaller additional effect. The effects of the surface roughness and phases and porosity found in the Pt layer on subsequently aluminized coatings performance are not known.