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Go to Editorial ManagerBrazing is one of the best methods of graphite to graphite or to metals joining. But the major problem associating the graphite brazing is the poor wetting by the conventional molten fillers. For this reason, scientists have produced a special filler metal based on active elements which interacts with graphite to form carbides. Also, recently another technique to overcome the wetting problem was introduced by H. Ohmura and T. Yoshida. It included inserting an intermediate layer of pure iron foil inside the copper filler. In the present work, another filler combination of Cu/ steel/Cu foils is proposed as new filler technique for graphite brazing. It was found that, it produced a succeeded joint with a good properties consisted of a columnar phase which resulted from the partially dissolution of iron in molten copper. Additionally, the increasing of brazing time caused reducing the thickness of the steel central layer and increasing the thickness of the columnar phase layers. The x-ray diffraction test developed that, the joints contained two carbide types, iron and copper free elements.
The objective of this research is to characterize new technique of copper filler addition to the brazing joints of 316L stainless steel to overcome the wetting problem between them. This technique includes the electrochemical deposition of copper on the stainless steel joint parts to insure optimum coinciding, minimum oxidation during brazing heating, and consequently good wetting and bonding. An evaluation of the present technique and a comparison with traditional one were performed. The samples ware tested to find the shear strength, microhardness, microstructure and x-ray diffractometry. In general, the present new electrodeposited fillers were clearly better than the traditional filler in producing perfect joints with higher shear strength. On the other hand, there was an opportunity of production acceptable joints with electrodeposited fillers under air environment.