Bonding solid-state diffusion

In 1902, Wagner published an analysis, based on diffusion reactions, of the oxidation of the surface of a metal. His interpretation has remained a classic in solid state diffusion analysis. The surface of a metal consists of metal atoms bound to the inner structure by a series of hybrid-bonds. If oxygen gas is present (air), the metal can form an oxide coating ... 

At site 8, an increase in copper concentration was observed simultaneously with a decrease in gold and silver concentrations. The two caps, previously well-fitted, were joined by the process known as solid-state diffusion bonding with copper salts in a reducing atmosphere. The process took place at about 890 °C (10). The relatively low temperature permitted joining at site 8 without desoldering the join at site 6, only 1.5 mm distant. This joining method was widely used by the Etruscans in their famous granulation work. 

Solid-state brazing is simply a process of solid-state diffusion. Solid-state brazing occurs at a rate which is temperature dependent, meaning that less time is required to achieve a satisfactory solid-state diffusion bond at higher temperatures. To realize diffusion times of the order of a few hours, the temperature should be at least 500 °C, perhaps 600 °C and the parts (membrane and adjacent... 

Further methods have been developed for Al-SiC and Ti-SiC MMCs which make use of diffusion bonding/solid-state processing of stacks of plasma sprayed foils or stacks of alternating metal foils and fiber fabrics (foil-fiber-foil). 

Excluding contamination by adapting well controlled processing methods also facilitates the production of high toughness interfaces. Consider as an example the interface between 7-Ni(Cr) and o -Al203. When this interface is produced by solid-state diffusion bonding, the... 

Solid state diffusion bonding 1200-1500°C, 3-50 MPa 1500°C, 3-17 MPa Ti3SiC2) Ti5Si3Cx, TiC, TiSi2 MosSisCx, M02C... 

Sintering Bonding particles together by solid state diffusion to the contact points at an elevated temperature and sometimes under pressure. In many cases a small amount of bonding fluid may be present, such as in glass-bonded sintered alumina. See also Hot isostatic pressing (HIP). 

Gold s low elastic modulus and rapid self-diffusion are beneficial for solid-state diffusion bonding. 

On the other hand, the reliability of the product improves, too, if each state of the plasticity deformation, the creep deformation, and the diffusion joint in the solid phase diffusion bonding as the bonding process, is accurately understood, and the bonding process is controlled properly. 

---