Reaction mechanism between oxide film on surface of Al-Li alloy and CsF-AlF3 flux

The composition of the oxide film on the surface of Al-Li alloy was measured after accelerated oxidation at 500 and 540 °C, and the reaction mechanism between CsF-AlF3 flux and the oxide film on the surface of Al-Li alloy was also discussed. The results show that the oxide film on the surface of Al-Li alloy is mostly composed of Li2CO3 and amorphous Al2O3. The brazing technology for Al-Li alloy is accomplished using the improved CsF-AlF3 flux. The improved flux CsF-AlF3 can effectively remove the oxide film by the way of reacting and/or dissolving the oxide film, of which CsF compound plays an important role in the course of removing the oxide film. The key step is the generation of HF, which induces and accelerates the reaction of removing oxide film. The generation of H2O also accelerates the reaction.