6063铝合金氧化膜与CsF-AlF_3及KF-AlF_3钎剂的反应机制

Mechanism of CsF-AlF_3 and KF-AlF_3 fluxes reacting with oxide films of 6063 aluminum alloy

选用CsF-AlF3和KF-AlF3钎剂,研究了两种钎剂在6063铝合金表面不同温度下的去膜效果,并分析和探讨了钎剂与6063铝合金表面氧化膜的反应机制.研究发现,CsF-AlF3钎剂是以反应、溶解的机制去除6063铝合金表面氧化膜的,NH4F在高温下生成的HF是CsF-AlF3钎剂去膜的关键化合物.此外,H2O的存在或形成促进了HF的生成,从而加速了钎剂的去膜进程.CsF-AlF3钎剂反应产物中没有发现CsF和AlF3,只有少量的CsAlF4存在.在570℃下,KF-AlF3钎剂反应产物中以KAlF4为主,而在610℃条件下,KAlF4已不存在,只有少量的KMgF3生成.结果表明,在610℃条件下,Mg,Mn元素和KAlF4将逐渐地消耗掉,使得钎剂熔点急剧升高,导致钎剂流动性变差.

CsF-AlF3 flux and KF-AmF3 fluxes were selected,the effects of removing the oxides on the surface of 6063 aluminum alloy by these two fluxes were studied at different temperatures,and then the reaction mechanism between flux and surface oxide film of 6063 aluminum alloy was analyzed and discussed.It is discoved that the oxide film on the surface of 6063 aluminum alloy was removed by CsF-AlF3 flux in a reacting and/or dissoluting way,and the HF formed at high temperature from NH4F was the critical compounds existed in the CsF-AlF3 flux.In addition,the formation of HF was improved and accelerated duo to the H2O,hence the process of removing the oxides was accelerated by the flux.The CsF and AlF3 were not found,and only a few amount of CsAlF4 was found in the residuai of CsF-AlF3 flux,and also,the main residua of KF-AlF3 flux was KAlF4 at the 570 ℃,KAlF4 was not found at the 610 ℃,which only a few amount of KMgF3 was found.Results also indicated that in the residua of KF-AlF3 flux,Mg,Mn and KAlF4 would loss gradually,which lead to the melting point of flux increasing rapidly and the flux fluidity became poorer.