Vacuum diffusion welding and vacuum brazing

Diffusion welding is a welding method in which the weldments are closely bonded and kept at a certain temperature and pressure for a period of time, so that the atoms between the contact surfaces are diffused to form a connection. Because welding is usually completed in high temperature environment, in order to avoid oxidation of weldments under high temperature, vacuum protection is generally used, so it is also called “vacuum diffusion welding”.

It is especially suitable for welding dissimilar metal materials, non-metallic materials such as graphite and ceramics, dispersion strengthened superalloys, metal matrix composites and porous sintered materials.

Vacuum brazing: it uses the metal material whose liquidus temperature is lower than that of the base metal’s solidus temperature as the filler metal, heats the parts and solder until the solder melts, uses the liquid solder to wet the base metal, fills the joint gap, and dissolves and diffuses with the base metal, and then the liquid solder crystallizes and solidifies, so as to realize the connection of parts (the weldment is not melted, only the solder is melted).