铜浸镀锡层的宏、微观形貌形成过程

Formation Process of the Microcosmic and Macroscopical Morphology of Immersion Tin Plating onto Copper Substrate

以硫脲作为电位调整剂,以甲烷磺酸锡为主盐的酸性溶液作为镀液,采用浸镀法在铜基材上制备了锡镀层。采用场发射扫描电子显微术(FESEM)和X射线衍射(XRD)表征锡镀层的组织结构,数码相机微距照片表征镀层的宏观形貌。研究表明,该镀液体系浸镀锡可以获得光滑而致密的浸锡层,无枝晶形成。该镀层主要相结构为体心四方的白锡。镀层的形成可分为锡晶粒的剧烈瞬间形核、平面层状生长和镀层致密化排列3个阶段。

The tin coatings are prepared by immersion plating method on the copper substrate.The acid plating solution is used in which thiourea is added as the potential adjusting agent,and the stannous methanesulfonate is used as the primary salt.The tin coating is characterized by a field emission scanning electron microscopy（FESEM） and the X-ray diffraction（XRD）.The macroscopical morphology is researched by the numeral photos.The results show that in this methanesulphonic acid based plating baths,the glossy and compact tin coatings without dendrite tin growth can be obtained by immersion plating.The main phase structure of the coating is tin with body-centered tetragonal crystalline structure.The formation of the coating can be divided into three stages： exquisite instantaneous nucleation,planar sandwich growth and coating closed-grained growth.