| Sil-fos™5 is used to braze copper and copper alloys. When brazing copper the phosphorus within the alloy imparts a metallurgical based self-fluxing capability. When Sil-fos™5 is used to join copper alloys (such as brass, bronze or gun metal) a separate flux will be required because the self-fluxing action only occurs on copper. This filler metal should not be used to braze iron containing materials like carbon or stainless steels or nickel containing materials as the phosphorus within the filler metal will form brittle, intermetallic, phosphide compounds, at the joint interface. Sil-fos™5 is not suitable for use in sulfurous atmospheres at elevated service temperatures. Phosphorus is the key element, the higher this is the more free flowing the filler metal, but the lower its ductility. Silver is used to improve the filler metal’s ductility, but reduces its flow properties. Sil-fos™5 provides the best combination of flow and ductility of all the silver-copper-phosphorus type brazing filler metals. The optimum joint gap for brazing is normally 0.05-0.2mm. Sil-fos™5 is extensively used in refrigeration, air conditioning and heat-exchanger components for flux-free brazing of copper pipes and tubes. It is also used for joining copper in electrical engineering applications. Information provided by Johnson Matthey Metal Joining |
