WETTING OF COPPER BY NI-P BASED BRAZING A LLOYS

Wetting of copper by three binds of Ni-P based brazing alloys (NiP10, NiCr14P10 and NiNb10P10) was studied. All three alloys wet copper just after melting. Chromium and niobium improve wetting of copper relativ ely to the Ni-P braze. The interface between copper and brazing alloys in all cases is a solid solution of copper in Ni-P or Ni-Cr-P or Ni-N b-P, either as a diffusion zone or as a homogeneous layer. Due to the interaction of copper and brazing alloys a Ni3P phase arises in each b raze containing copper in NiP10, chromium in NiCr14P10 and niobium in NiNb10P10, and a Ni based solid solution containing copper in each bra ze and chromium and niobium in NiCr14P10 and NiNb10P10 brazing alloys, respectively.