Effect of trace calcium on melting behavior of Ag-Cu-Zn brazing alloy by thermal analysis kinetics

The purity of the brazing alloys applied is necessary to be improved with the increasing cleanness of steel.Calcium is easily brought into the widely used brazing alloy,Ag-Cu-Zn,during the producing process.This paper aims at revealing the effect of calcium on the melting behavior of the brazing alloy.The thermal analysis kinetics of silver alloy with trace calcium was studied by using differential scanning calorimetry（DSC）,and the enthalpy peaks were analyzed by differential methods.The rate constant of phase transformation in the probable brazing temperature range goes up with increasing calcium content,according to the values of the apparent activation energy,E,and the frequency constant,A.It is concluded that the calcium addition could improve the melting performance of Ag-Cu-Zn brazing alloy.