【作者】 刘昕；

【导师】 雷永平；

【作者基本信息】 北京工业大学 ， 材料加工工程， 2004， 硕士

【摘要】 摘要 采用机械合金化(MA)可直接制备无铅钎料粉体，MA 在控制钎料成份和杂质分布，细化第二相的尺寸，并使其实现弥散分布等方面具有独特的优势，因此有着重要的工程应用价值。另外，利用机械合金化制备钎料粉体，是一种新的探索，其中合金元素的相互作用，新相的形成，合金粉体与磨料介质之间的相互作用等机理性研究具有重要的理论意义。 本文在大量试验的基础上，确定出适合于制备无铅钎料粉体的主要工艺参数。利用扫描电镜(SEM)、差热分析仪(DTA)、X 射线衍射仪(XRD)对 Sn-0.7Cu、Sn-3.5Ag 合金粉末的形貌、机械合金化进程、球磨条件对机械合金化合金相的影响、机械合金化 Sn-0.7Cu、Sn-3.5Ag 的反应机制进行了研究。将 MA 制备的钎料粉体与 RMA 型焊剂相配合，并制成焊膏。研究了铺展试样的微观组织和搭接接头的力学性能，并与熔炼法制备的无铅钎料进行对比。 结果表明，通过对球磨工艺参数的选择和优化，采用机械合金化可制备出无铅钎料粉体。金属粉末的最终颗粒尺寸可通过合适的工艺参数来控制。加入丙酮可明显加速MA进程。球磨条件对MA合金相的形成有很大的影响。对于Sn-Cu、Sn-Ag二元系，其MA过程是一个反复地冷焊、断裂的过程，并形成复合层片状组织；其机械合金化反应机制是通过机械诱发原子扩散，使原子间发生置换固溶和晶界溶解，而逐渐形成Cu6Sn5、Ag3Sn等合金相。 采用MA法制备钎料的铺展面积及润湿角与采用熔炼法制备钎料的铺展面积及润湿角差别不大，但前者的接头强度较低于后者的接头强度。Sn-0.7Cu(MA)的金相组织由富Sn相、Cu6Sn5和少量Cu3Sn相组成。而Sn-3.5Ag(MA)的金相组织中由于紫铜基板中的Cu原子向钎料中的扩散，使其微观组织中出现Cu6Sn5相，而在基体上则均匀分布着富Sn相和Ag3Sn相。更多还原

【Abstract】 Mechanical alloying (MA) technology is a new process to prepare solderpowders. There are particular advantages in controlling the composition of solderalloy, the distribution of impurities, the refining and dispersion of the second phase.In addition, MA process is a new exploration in the preparation of solder powders. Itis very important to investigate theoretically the reciprocity of alloy elements，theformation of new-phase and the interaction between alloy powder and milling media. The primary MA parameters in the preparation of lead-free solder powders wereobtained based on a number of experiments. Morphology of Sn-0.7Cu and Sn-3.5Agpowders, the course of mechanical alloying and the effect of ball milling conditionson the formation of mechanical alloy were analyzed using a scanning electronmicroscope (SEM), a differential thermal analyzer (DTA) and an X-raydiffractometer (XRD). The reactive mechanism of mechanical alloying Sn-0.7Cuand Sn-3.5Ag was educed. The microstructure and regular mechanical property oflead-free solder paste made from MA powders and RMA flux was investigated,compared with the ones made from cast. The results show that the lead-free solder powders and the size of particles canbe controlled under the proper MA parameters. As a surfactant, acetone appears to beeffective to accelerate the MA process. Ball milling parameters effects the formationof MA alloy significantly. The course of mechanical alloying Sn-Cu and Sn-Ag isdescribed as bonding and rupturing time and again, ensuing from which sheetmicrostructure was formed. The reactive mechanism of mechanical alloyingSn-0.7Cu and Sn-3.5Ag is that the mechanical-induced atom diffusion drivessubstitution solid solution and interface dissolution, as a result of which Cu6Sn5 andAg3Sn was formed. There is no distinct difference in spreading area and wetting angle between MApaste and cast solder, but the shear strength of the former is less than the one of thelater. The microstructure of Sn-0.7Cu (MA) is composed of Sn-rich phase, Cu6Sn5and Cu3Sn phase IMCs. The microstructure of Sn-3.5Ag (MA) is made up of Cu6Sn5 - II -<WP=6>ABSTRACTphase that was formed by copper atoms diffusion from copper board, Sn-rich phaseand Ag3Sn that evenly distributed in base body.更多还原