ABSTRACT
The three joining processes that will be described here are soldering, brazing, and solid-state diffusion bonding. Soldering and brazing both involve using a ller metal that is heated above its melting point, made to wet the mating surfaces of a joint, with or without the aid of a chemical uxing agent, leading to the formation of metallurgical bonds between the ller and the respective components. By convention, the joining process is dened as soldering if the ller metal melts below 450°C and as brazing if it melts above this temperature. In both soldering and brazing, it is uncommon for the original surfaces of the components to be eroded by reaction with the ller beyond the microscopic level (<100 μm). Solid-state diffusion bonding involves placing surfaces of two components in contact under a loading that at the least is provided by the weight of the upper component and heating the assembly until the voids at the interface have been removed by diffusion (see next section).
