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Coating of high-efficiency lead-free soldr particles with antioxidation film and its evaluation

高效无铅焊料颗粒抗氧化膜包覆及其评价

基本信息

批准号：
14550741
负责人：
SATOH Munetaka
金额：
$ 2.37万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14550741/
关键词：
Lead-free solder Wax coating Mechanical energy Elution test Flux Solder paste Powder design Rheological Characteristics

项目摘要

Spherical copper particles were used as model particles of lead-free solder particles. The copper particles were coated with wax powder by means of a dry mechanical method using a ball mill and the antioxidation film was formed on the surface of copper particles. The mechanical energy applied to the copper particles during the film formation processing was evaluated using the relationship between the compressive energy and the strain of a copper particle, which was measured by the unconfined compression test for a single particle. The optimal operating conditions of the ball mill in the processing were determined based on the applied energy in which the copper particles hardly deformed. The elution test in which the wax-coated copper particles were soaked in a dilute nitric acid solution proved that the wax film on the particles prevented the elution of copper to the nitric acid solution. The alloy particles of tin and zinc which were one of the representative lead-free solder particle … More s and were softer than the copper particles were coated with the wax powder using the same method. The solder paste was prepared by kneading the flux with the wax-coated alloy particles and stored at low and room temperatures for a given period of time. The pastes were melted on a copper plate to evaluate the wettability. The results showed that the wax film prevented the oxidation of the alloy particles and the paste including the wax-coated alloy particles had the satisfactory wettability.The flowability of the solder pastes was evaluated with a capillary rheometer. In order to investigate the influence of the particle content in the paste, the wax coating and the particle shape (the strain of particles) on the flowability, the exit velocity of the paste from the capillary was measured under various conditions and then the viscosity coefficient was determined. The results showed that the flowability was maintained even though the particle content was 89.5 wt% (corresponding to 50 vol%) and decreased with increasing in the particle deformation (the strain). The viscosity coefficients of the pastes including the particle having the strain less than 0.1 and the wax-coated particles in which the film thickness was less than 1μm were almost equal to that of untreated spherical particles. It has been proved that the mechanical processing method developed in this study enables the powder design of high-efficiency lead-free solder particles. Less

采用球形铜颗粒作为无铅焊料颗粒的模型颗粒。采用球磨机干式机械法在铜颗粒表面涂上蜡粉，在铜颗粒表面形成抗氧化膜。通过对单个铜颗粒进行无侧限压缩试验，利用压缩能与铜颗粒应变之间的关系来评估在成膜过程中施加在铜颗粒上的机械能。在铜颗粒基本不变形的条件下，确定了球磨机的最佳操作条件。将蜡包覆的铜颗粒浸泡在稀硝酸溶液中的洗脱试验证明，颗粒上的蜡膜阻止了铜在硝酸溶液中的洗脱。采用同样的方法，对具有代表性的无铅焊料颗粒之一锡、锌合金颗粒进行了蜡粉包覆，得到了比铜颗粒更细、更柔软的锡、锌合金颗粒。通过将助焊剂与涂蜡合金颗粒捏合制备锡膏，并在低温和室温下保存一定时间。浆料在铜板上熔化以评价其润湿性。结果表明，蜡膜可以防止合金颗粒氧化，蜡包合金颗粒膏体具有良好的润湿性。用毛细管流变仪对锡膏的流动性进行了评价。为了研究膏体中颗粒含量、蜡包覆层和颗粒形状（颗粒应变）对膏体流动性的影响，测量了膏体在不同条件下从毛细管流出的速度，并确定了膏体的粘度系数。结果表明，当颗粒含量为89.5 wt%（相当于50 vol%）时，其流动性仍保持不变，且流动性随颗粒变形（应变）的增加而降低。应变小于0.1的颗粒和膜厚小于1μm的涂蜡颗粒的黏度系数与未处理的球形颗粒的黏度系数基本相等。实践证明，本研究开发的机械加工方法能够实现高效无铅焊料颗粒的粉末设计。少