Cu-p Base Amorphous Brazing Performance, And Brazing Machine Management

The silver-based solder has moderate melting point, good technology, and good strength, toughness, electrical conductivity, thermal conductivity and corrosion resistance, is very broad application of hard solder. But most of the silver-based solder are toxic element cadmium, and high cost. To avoid pollution of the environment, reduce costs, on behalf of the silver solder is always one of frontier research in the field brazing and hot, with great economic and social benefits.Traditional copper-phosphorus solder with low melting point, good fluidity, the temperature close to the silver brazing filler metals. Can be a good wetting of copper and its alloys, Brazing of P can also reduce copper oxide, generated after reduction of the oxide into the liquid metal surface was covered to prevent oxidation. So when soldering copper without flux, solder joints with high strength and electrical conductivity, and the brittle than the solder joint itself is small, is 500 ~ 800℃temperature range of brazing copper and copper alloy to replace silver-based solder material is an ideal material. However, the traditional copper-phosphorus solder containing P are within the 5%, due to high phosphorus content in solder matrix contains large amounts of brittle compounds Cu3P, lead solder brittle at room temperature, joint strength and toughness than the difference between silver-based solder many solder processing difficulties, made using traditional methods is difficult to foil; the other hand, phosphor copper solder impatience of the corrosion of ferrous metal, the wettability is poor, and with elements such as Fe and Ni reacts brittle phase, Therefore, the scope of its application was limited. Actual production need a better soldering properties of phosphorus-based solder copper.How to maintain the advantages of copper phosphorus brazing are based on further improving its performance, especially at room temperature brittle and can be molded, so as to expand its scope of application is the development of a solder direction. Making use of rapid solidification of amorphous brazing technology is to obtain good overall performance Cu-P filler metal is one important means, and can greatly simplify the process.Amorphous solder melting point solder melting point lower than the average, the tensile strength and impact strength of weld is better than silver solder, so not only for ordinary copper and copper alloy brazing, also used in demanding high-tech fields precision, high-reliability soldering occasions. U.S., Japan and other developed countries have replaced their traditional solder, as a new generation of solder used in aerospace, aviation, electronics, energy, transportation, military, automotive, and civil and other industries. But compared with developed countries, the domestic is still lagging behind, so to carry out copper phosphorus brazing of amorphous far.On the basis of theoretical analysis, several different componets of Cu-P based filler metals were designed and successfully prepared on single-roller rapid solidification equipment. The melting characteristics and structures of the filler metals were explored by means of DTA, XRD, etc. Based on study above, the rapidly quenched filler metal with excellent properties in this paper were used to braze copper. The impact of solder composition, structure, and brazing process on quenching filler metals wettability on copper, joint mechanical property and microstructure were studied. Brazing mechanism was studied by comparing amorphous filler metals with conventional filler metals.The results indicated that the filler alloy foils CuP7.7Sn5.4Ni14Si0.2,three Cu-P based filler alloy foils with Zr and CuP7.7Sn5.4Ni14Si0.2B0.03 are mainly of amorphous structure. CuP7.7Sn5.4Ni14Si0.2Zr0.04 conventional filler metal mainly consists of primary (Cu, Ni)3P,(α-Cu+Cu3P) eutectic and (α-Cu+Cu3P+δ) eutectic compositions. The wettability of quenching filler metals is much higher than conventional filler metals. Alloying elements Zr and B have played a beneficial effect on the wettability of filler metals, in which B affects obviously. With the increase of brazing temperature and brazing holding time, the wettability of filler metals increase; but when the spread area of filler metals decreases due to P evaporation. In the same process condition, the shear strength of amorphous brazing joints is higher than conventional filler metals. When the brazing temperature and brazing holding time increase excessively, the shear strength will decrease.The brazing joint consists of, interface area and diffusion zone. With the increase of brazing temperature and brazing holding time, the interface area of amorphous and conventional filler metal increases and the organizations of HAZ of base metal and brazinrg seam centre zone overgrow. Excessively high brazing temperature or long brazing holding time will produce brittle phase, but this effect on amorphous filler metals is much smaller. Study shows that in the same condition, amorphous filler metals interact with the base metal much more intensely than the corresponding conventional filler metals. The organizations in interface area and centre zone of amorphous brazinrg seam are evidently uniform and small. The diffusion of Sn,P is the best and Ni is the worst among all alloy element. With the increase of brazing temperature or brazing holding tim, alloy elements P,Sn diffuse intensely to base metal and this is good to get uniform and continuous solid solution interface area. But excessively high brazing temperature or long brazing holding time will result in producing brittle phase in interface area and make the jiont ability declined. In the same condtion, the possibility of producing P,Sn brittle compounds is small in amorphous filler metal's brazing seam interface zone.