Liquidus surface of quaternary copper phosphorus brazing filler metals with silver and tin.

Liquidus surface of copper phosphorus brazing filler metals with silver and tin addition was investigated. Spreadability and erosion of Cu-Ag-Sn-P quaternary filler metals on copper base metal were also studied. Primary phase could be predicted by using the phosphorus equivalent. The filler metals with the phosphorus equivalent more than 8.38 crystallizes Cu3P primary phase, whereas the filler metals with the value less than 8.38 crystallizes copper solid solution. The primary phase is also predicted by the electron concentration of filler metal, and also the ratio of electron concentration of tin plus phosphorus content to that of copper plus silver content. The erosion depth of copper base metal increased almost linearly with tin, silver and phosphorus content.