Experimental Results using a High Vacuum Soldering and Brazing Hood Furnace

摘要

Nowadays many components, for example devices used in electron microscopes, satellites or aircrafts, have to withstand challenging environments such as vacuum or extremely high temperatures. To manufacture reliable components like these a connection between dissimilar materials is often required. This connection can be metal-to-metal or even insulator-to-metal. It has to be strong, high temperature resistant and suitable for use in vacuum, as outgassing of flux material is not acceptable. The purpose of flux material is to remove remaining oxides and to reduce the surface tension in order to promote wetting of the dissimilar materials' surfaces. However, if exposed to vacuum or a high temperature environment, the effects of the flux on the electronic component are harmful. The flux material, which contains acid and salts, changes into the gaseous phase due to its high vapour pressure. The resulting condensation of the flux material on the insulators may produce conductive paths causing a leakage current. This process will destroy the expensive component. Unfortunately, the most active (and therefore corrosive) fluxes also form the strongest connections. Some material properties, for example vacuum resistance, cannot be obtained when manufacturing under conventional atmosphere conditions. One other problem with conventional atmospheres is that gas impurities are always embedded in the connecting surface.