Activating Precursors for Brazing Processes that Deposit Two Layers through Melting

Abstract

We present the manufacturing process, by melting in a controlled environment, of specific alloys that have a benefic effect on the diffusion phenomena’s in the base material of the addition coated rods for brazing. The friable precursors obtained by melting are grinded with the purpose of integrating them in the coat of the rods, namely the addition material. The metallurgic activation activity of the precursors is enhanced by using them as nano-powders in the coat of the rods.Of major importance for deep joint capillary brazing are the fluidity and superficial tension of the melt - addition material, or, in case of non-ferrous alloys, the degree of de-oxidation of base materials. In order to improve the above mentioned characteristics, we made precursors type: 5o% Cu-45% Sn-5% P (CIF); 92% Cu-2% Si 6% P- (RAV). The batch design was done by two distinct melting processes, in high frequency currents (CIF) and electric arc (RAV) in a controlled environment. The melts were cast in graphite forms as loose briquettes. The briquettes thus obtained were analyzed structurally and sclerometrically, and after testing, they were grinded in planetary mills until we obtained nano-powders. The resulting powders will be used, as required, to prepare brazing sheaths.