The role and application of potassium fluoaluminate brazing flux in aluminum industry.

Al and Al alloy surface easy to generate a layer of high density and chemical stability of Al2O3 membrane, especially when the mass fraction of Mg in the parent metal > 3%, the generation of Al2O3 + MgO style clearance oxide film, the chemical stability of higher, more difficult to eliminate.
The oxide on the surface of Al and Al alloy makes the solder in the brazing process condense into a ball and not wet with the parent material.
The purpose of the aluminum brazing agent is to remove the oxide film on the surface of the aluminum and reduce the wetting and spreading of the molten solder and the mother material.
In the process of aluminum and aluminum alloy brazing, traditionally chlorine salt flux is dominant, but this kind of soldering flux exists chloride halide ions such as electrochemical corrosion of parent metal has strong hygroscopicity strong, not easy to save;
In addition, after welding, the cleaning requirements of the residue are higher, otherwise, the soldering material will be seriously corroded after welding.
Potassium fluoaluminate is almost noncorrosive to the parent material, its spreading performance is excellent, no residue.

Such as the melting method, the grinding method and solid phase of fluoride potassium aluminate prepared flux contains free content, mostly to the welding work has corrosion effect, so in practice has been curbed, therefore preparation help welding performance good fluorine chemical precipitation method using potassium aluminate solder powder is effective and promising method.