Phosphorous Brazing Alloys – Self Fluxing

Brazing with Silver-Copper-Phosphorus and Copper Phosphorus alloys is widely used for the joining of Copper to Copper where the absence of a flux is a major benefit. The self-fluxing action of the Phosphorus ensures that flux entrapment problems are largely avoided and that high standards of joint soundness can be maintained.

High Phosphorus levels give excellent capillary penetration since the fluidity of the molten brazing alloy is controlled by the Phosphorus content Alloys with high Phosphorus content are less ductile than those with lower Phosphorus and higher Silver contents.

For applications where optimum mechanical strength, or resistance to vibration, is required the lower Phosphorus alloys are necessary (ie Phos 5, Phos 2, Phos 0R). The tin-containing alloy, Phos 0T, offers controlled fluidity, a low melting point and joints of good appearance. Phosphorus containing alloys should not be used on Ferrous or Nickel based parent alloys as they will result in brittle joints. This family of alloys can also be used for brazing high copper content alloys, providing that a suitable flux is used. Phos 15 is available in Strip form for the brazing of Electrical contact material.