Abstract: The present application provides improved diffusion coating compositions and improved methods for diffusion coating metal surfaces. The composition includes (a) a coating powder; and (b) a binder, wherein the coating powder comprises at least one metal, and wherein the binder will release an activator gas during vaporization or combustion. The method includes the steps of (a) providing a substrate; (b) applying a diffusion coating composition to at least a portion of the substrate, wherein the composition comprises a coating powder and a binder, the coating powder comprising at least one metal; and (c) vaporizing or combusting at least a portion of the composition so as to vaporize or combust at least a portion of the binder to produce an activation gas and vaporize at least a portion of the metal to form a coating of the metal on the substrate.