【作者】 王洪礼；

【导师】 路文江； 俞伟元；

【作者基本信息】 兰州理工大学 ， 材料加工工程， 2010， 硕士

【摘要】 为了解决铝铜直接钎焊时存在Al-CuAl2脆性相生成问题,采用电镀的方法在Zn-27Al薄带钎料的表面镀上一层Ni,通过控制电镀电压、通电时间以及电镀液温度等工艺参数,来控制镀层镍的含量,制备出形如Ni/Zn-Al/Ni式锌基复合钎料。采用差热分析(DTA)、X衍射分析仪(XRD)、润湿性、强度实验等方法,分析制备出来的新型锌基复合钎料的综合性能。讨论了该方法在制备新型锌基复合钎料方面的可行性。研究结果表明：其它条件不变时,通电电压3V,通电10分钟,电镀液温度20～30℃时,镀层厚度与镀层质量最为理想。制备出来的新型复合钎料形如Ni/Zn-Al/Ni形式,Ni在Zn-27Al基体表面形成均匀致密的镀层,且镀层结晶细致,平滑光亮,与基体层结合力强且易于弯折弯曲,无脆性之虞。与Zn-27Al钎料相比,新型复合钎料的固-液相线温度略微变化,并且润湿性能优良,在钎焊温度565℃时铺展面积达到最大值,钎焊接头抗剪强度较高。在氮气保护的电阻炉中用锌基复合钎料和Zn-27Al钎料对Cu与Al进行钎焊试验,利用光学显微镜、X射线衍射(XRD)、电子探针(EPMA)、扫描电镜分析(SEM)等多种现代测试手段,对钎焊接头进行微观组织分析并阐述Ni层的阻挡作用；研究结果表明：Cu-Al钎焊接头由Cu侧钎缝界面、中央钎缝区、Al侧钎缝界面三部分组成。复合钎料钎缝中AlCu偏聚在Cu侧、a-Al固溶体偏聚在Al侧的现象消失,组织分布更加均匀、且有少量的Ni3Al生成；Ni层能够有效的阻止Al和Cu的扩散,从而减少低熔点脆性Al2Cu化合物的生成,改善了接头性能。更多还原

【Abstract】 In order to solve the generation phase Al-CuAl2 brittleness of aluminum brazing copper existed direct,plating method was adopted by plating nickel on the surface of thin Zn-27A1 solder strip,controlling variables such as voltage,power time,plating bath temperature and the amount of nickel,the produced Ni/Zn-Al/Ni type zinc-based compound filler.Function was explored by means of differential thermal analysis(DTA),XRD,wettability,strength experiments,etc.Besides,feasibility of this plating method has also been discussed for producing the new zinc-based filler metals.The results show that with the power voltage of 3V,electricity for 10 minutes,plating bath temperature of 20～30℃and the other conditions unchanged,the coating of nickel is of the best thickness and quality.The newly produced composite filler is Ni/Zn-Al/Ni fillers and the nickel covering is tense,crystalline coating and detailed,smooth light and the substrate layer is combined with strong,even and quite flexible,and bend curl,non-brittle risk.Compared with Zn-27A1 solder,this compound fillers solid-liquid line temperature has changed a litter or so and the spreading area can reach the maximum under 565℃.The brazed joints are of higher shear-resistance.Aluminum and copper had been brazed with zinc base composite filler metal and Zn-27Al filler metal in furnace protected by the nitrogen.The phase change in brazing process has been studied by means of electron probe microanalyser (EPMA),X-ray diffraction(XRD) and scanning electron microscope(SEM),and explain the role of Ni barrier layer.Experimental results showed that the Cu-Al brazing filler metal includes a transition region on Cu side,the central solder joint area and a transition region on Al side at that time.the brittle intermetallic compound CuAl in the Cu side and a-Al solid solution segregation in the Al side dispersed and the organization distributed more evenly,and a little Ni3Al compounds appeared in joint brazing with zinc base composite filler metal.Ni coating can effectively prevent the spread of Al and Cu,and can reduce the formation of low melting point brittle Al2Cu compounds,the joint property is improved.更多还原