High-Temperature Diffusion Brazing
A thermal joining process in vacuum or protective gas where melting-point depression elements diffuse into the base metal through isothermal solidification. This drastically increases the high-temperature strength of the joint.
In diffusion brazing, you join parts in a vacuum or under protective gas without the base material melting. The filler metal is heated and the alloying elements diffuse into the joint zone and the base material. It is important that the temperature remains constant throughout the holding time and that you cool down slowly, otherwise the structure becomes uneven and the joint can become brittle or crack. Process times are long because diffusion needs time, and you must have precise temperature control to avoid distortions or stresses.