Abstract: A method of joining superalloy substrates together comprises diffusion bonding the superalloy substrates by depositing an activator directly on the surface of the joint to be bonded and thereafter subjecting the joint to heat and pressure. The heat and pressure causes the surface of the superalloy, in the presence of the activator, to diffusion bond without the use of a brazing alloy. By eliminating the brazing alloy, a high strength, high temperature bond is achieved, yet there is no molten brazing alloy to be drawn through capillary action into any fine features surrounding the joint being bonded, and there is no residue left at the interface that would diminish the mechanical properties of the joint.