Effects of the Chemical Compositions of KF-CsF-AlF_3 Middle Temperature Aluminum Flux on Melting Characteristics

摘要

According to the KF-CsF-AlF3 ternary phase diagram, 25 samples (named 'group A') near the region around the E_4 and E_5 (ternary eutectics points), and 22 samples (named 'group B') near another region around the e_5 (binary eutectic point) and m_2 (ternary eutectics point) were prepared by the wet synthesis method. The melting curves of these samples were measured by differential scanning calorimetry (DSC). Based on the DSC data, the effects of the flux's compositions on the melting characteristics were analyzed and summarized. The results indicated that the lowest solidus of group A samples was about 480°C, meanwhile, their liquidus was about 520～530°C, and the melting range was approximately 40°C. Furthermore, when the content of CsF was lower than 18mol%, the solidus of group A samples apparently rose to about 510°C, but the liquidus did not change greatly. The lowest solidus of group B samples was about 420°C, meanwhile, their liquidus was below 450°C, and the melting range was approximately 20～30°C. So, with this profile of melting characteristics, some of the samples of group B flux would be good substrates for aluminum alloy middle temperature brazing, with good prospects for application.