银基钎料在制造业中的研究进展

钎料的性能很大程度上决定了钎焊接头的质量和钎料的应用范畴.银基钎料作为一类非常重要的硬钎焊材料,其填缝能力优异,强度与黄铜、低碳钢接近,可钎焊除铝、镁合金等轻金属之外的所有金属材料.因此,银基钎料广泛应用于航空航天、超硬工具等制造领域,并且受到国内外钎焊界学者们的高度关注.然而,银基钎料的发展及应用过程中仍存在以下问题:第一,钎料中贵金属银含量偏高(一般高于45%),导致钎料使用成本高;第二,银基钎料挤压、轧制、拉拔等加工过程中不可避免地存在夹杂物,影响钎料的使用性能和连接质量;第三,有益金属或合金调控钎料及其连接性能的机制较为复杂,尚未完全研究清楚;第四,传统制备银基钎料的方法产能低下;第五,银基钎料在制造业领域的应用研究尚未见系统报道.国内外对于银基钎料钎焊性能及工程应用方面的研究主要集中于:(1)开发多种节银降银钎料,主要是有益元素调控银基钎料连接性能方面的研究;(2)改进钎料的传统加工方法,提出新的制造方法,如粉末电磁压制成形、钎焊过程中原位合成、快速凝固、镀覆扩散组合等;(3)研究杂质元素(C、Ca、S、Al、Fe、Bi、Pb、O、N 等)的影响;(4)银基钎料形态创新研究,如三明治复合钎料(中间为铜合金、两边为银钎料)、箔带钎料、镀锡银钎料等;(5)工程应用研究,银基钎料在航空航天、汽车制造、电力能源等工业领域起着不可替代的作用,但目前国内外仍缺乏系统阐述该方面研究的报道.因此,本文对近20年国内外有关银基钎料的研究报道进行了评述,重点讨论了合金元素对银基钎料性能的影响.首先对银基钎料研究现状进行详述,总结了Cu、Zn、Sn、Ga、In、Ni、Mn、Cd、Li、Ce、La、P、Si、Pr在银基钎料中的优缺点,归纳了杂质元素C、S、O、N、Ca、Al、Fe、Pb、Bi的恶化作用.其次对银基钎料在航空航天、汽车制造、电力能源、超硬工具、家用电器、眼镜行业等制造业中的应用研究进行详细介绍.最后提出银基钎料研究和应用中的不足,为银基钎料的深入系统研究及相关技术发展提供理论指导.

Research and Application of Silver-based Brazing Alloys in Manufacturing Industries:a Review

The properties of the brazing filler metals largely decide the quality of brazed joints and application field of brazing filler metals.As an important brazing filler metal,the silver-based brazing alloy possesses excellent filling capacity and high strength (close to brass and low carbon steel),which can braze nearly all the metals except aluminum alloys,magnesium alloys and other light metal materials.Consequently,silver-based brazing alloy has been widely used in aerospace,super-hard tools and other manu-facturing industries,and aroused extensive attention of researchers at home and abroad. Nevertheless,there are still some problems in the development and application of silver-based brazing alloys.Ⅰ.The high silver content always leads to high costs of filler metals.Ⅱ.The inclusions can't be avoided during the process of extrusion,rolling,dra-wing and so forth,which are harmful to the performance and quality of brazed joints.Ⅲ.The mechanism of controlling the properties of brazing alloys and brazed joints by adding beneficial pure metal or alloys is still confused.Ⅳ.The production efficiency of silver-based brazing alloys by traditional process is low.Ⅴ.The application of silver-based brazing alloys in manufacturing industry has not been reported systemically. The research on the brazed joints and engineering applicationsof the silver-based brazing alloys at home and abroad mainly focus on the following aspects.(Ⅰ)Develop brazing alloys with lower silver content.It mainly use selected element to modify the connec-tion properties of brazed joints.(Ⅱ)Improve traditional preparation methods of silver-based brazing alloys,namely,propose new methods,such as powder electromagnetic suppression forming,original position synthesis in brazing process,rapid solidification, coating diffusion etc.(Ⅲ)Study the effect of impurity elements,like C,Ca,S,Al,Fe,Bi,Pb,O,N etc.(Ⅳ)Design silver-based brazing alloys with innovative shape,such as sandwich-like,foil and Sn-plated filler metals etc.(Ⅴ)Explore engineering application. Silver-based brazing alloys have been widely applied in aerospace,automobile manufacturing,electric energy,while it still lack inten-sive study on industrial application. Accordingly,this article reviews the relevant researches on silver-based brazing alloys in recent 20 years,and mainly focus on the effect of alloying elements on the properties of silver-based brazing alloys.First of all,the research status of silver-based brazing alloys is outlined.The effects of Cu,Zn,Sn,Ga,In,Ni,Mn,Cd,Li,Ce,La,P,Si,Pr on silver-based brazing alloys are summa-rized,including their advantages and disadvantages.Meanwhile,the negative effects of C,S,O,N,Ca,Al,Fe,Pb and Bi are pointed out.Secondly,the applications of silver-based brazing alloys in manufacturing industries,including aerospace,automobile manufacturing,electric energy,super-hard tools,household appliances,optics are concluded in detail.At last,the existing problems in the research and application of silver-based filler metals are put forward,which will provide theoretical guidance for the in-depth systematic study of silver-based brazing alloys.