热浸镀锡铜磷钎料的性能

以Cu93P钎料为基体，在其表面热浸镀锡，制备CuPSn钎料，采用扫描电镜、万能力学试验机、显微硬度计、差热分析仪、箱式电阻炉和体视显微镜分析锡镀层的界面形貌，钎料的抗拉强度、显微硬度、熔化温度和润湿性。结果表明：在Cu93P钎料表面热浸镀锡过程中，液态锡与钎料发生了界面反应，生成Cu₆Sn₅金属间化合物，即钎料基体与锡镀层形成良好的冶金结合；随着热浸镀温度的升高和时间的延长，CuPSn钎料的抗拉强度和显微硬度均呈降低趋势，抗拉强度的降低源于界面处产生的Cu₆Sn₅脆性化合物和孔洞，显微硬度的降低源于热浸镀的去应力退火作用；Cu93P钎料表面热浸镀锡可降低钎料的熔化温度，提高钎料的润湿性，Cu93P钎料表面热浸镀5.20%（质量分数）锡之后，Cu88.16P6.64Sn5.20在纯铜板上的润湿铺展面积比基体Cu93P钎料增加43.15%。

Properties of Cu-P Brazing Filler Metal After Hot-Dip Tinning

The CuPSn brazing filler metal was prepared on the basis of Cu93P brazing filler metal by hot-dip tinning. The interface morphology of tin coating was observed by scanning electron microscope. The tensile strength, microhardness, melting temperature and wettability of the brazing filler metal were investigated by universal mechanical testing machine, micro-hardness tester, differential thermal analyzer, resistance furnace and stereomicroscope. The results indicate that the liquid tin reacts with the brazing filler metal to form Cu₆Sn₅ intermetallic compound during hot-dip tinning, which means that the brazing filler metal and tin coating form good metallurgical bonding. The tensile strength and microhardness of brazing filler metal decrease with the increase of hot-dipping temperature and time. The decrease of tensile strength is due to the formation of Cu₆Sn₅ brittle compound and pores at the interface, and the decrease of microhardness is due to the stress-relieving annealing effect of hot-dip. Hot-dip tinning can reduce the melting temperature and improve the wettability of the brazing filler metal. The wetting area of brazing filler metal increases by about 43.15% compared with that of the matrix when 5.20wt% tin is hot dipped in it, and the Cu88.16P6.64Sn5.20 brazing filler metal possesses a good wettability.