Reactive Partial Transient Liquid Phase Bonding (R-PTLPB) of YSZ to Crofer22APU Using Nickel and Copper-Nickel as Core Interlayers

摘要

High temperature applications demand high quality and reliable joints, which offer an outstanding corrosive and thermal resistance. These requirements have pushed conventional brazing technologies to their limits. One new possibility to solve this problem is reactive partial transient liquid phase diffusion bonding, which combines an active interlayer with a melting point depressing core layer to bond dissimilar materials. Diffusion processes lead to an isothermal melting and solidification of the materials. The result is a bond with a high re-melting temperature and a good microstructure. In the conducted experiments, YSZ was joined to Crofer22APU by using zirconium and titanium as active elements. The active elements were applied by means of physical vapor deposition (Arc-PVD). The amount of the active elements was varied. Nickel and copper-nickel foils were utilized as core layers. The influence of different bonding temperatures, the fixturing force, the holding time, and the different active elements on the microstructure were studied and evaluated.