| 摘要: |
| 针对铝合金盘基片镀镍过程中产生的凹点型缺陷导致基片报废的问题，采用扫描电子显微镜、聚焦离子束显微镜对计算机硬盘用铝合金盘基片的微观组织缺陷进行分析，并通过实验室模拟化学镀镍前处理过程，观察前处理对铝合金盘基片表面形貌、相分布与表面润湿性的影响。结果表明：发现在前处理过程中铝合金表面析出相周围的铝基体发生溶解，造成析出相脱落，形成微孔。而深度较大的微孔由于气体难以及时排出，溶液难以浸没，造成微孔底部Zn覆盖较少。说明在镀镍过程中，基片浸入镀镍溶液时深度较大的微孔中的气体同样无法全部及时排除，造成微孔处无法发生镀镍反应，使得微孔处形成孔洞，最终造成镀层表面的凹点型缺陷。 |
| 关键词: 铝合金盘 金属间化合物 化学镀镍 润湿性 微观组织缺陷 |
| DOI：10.11933/j.issn.1007-9289.20180122001 |
| 分类号:TG174.441 |
| 基金项目: |
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| Defect Formation Mechanism of Electroless Nickel Plating on Aluminum Alloy Disk |
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RAN Hong-feng, XIAO Jiang-chu, ZHU Yi
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Shenzhen Kaifa Technology Co., Ltd., Shenzhen 518035
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| Abstract: |
| In view of the pit defect caused by the nickel plating of the aluminum alloy disc substrate, resulting in substrate scrap, the microstructure defects of the aluminum alloy disc substrate were studied by scanning electron microscope (SEM) and focused ion beam microscope (FIB). The influence of the pretreatment process on the surface morphology, phase distribution and surface wettability of aluminum alloy surface were analyzed through the simulation of electroless nickel plating pretreatment process. The result show that the aluminum matrix around the intermetallic compounds dissolves during the pretreatment, causing the precipitated phase (intermetallic compounds) to fall off and forming micro-pits. When the micro-pit is of deep size, it is difficult for the gas to discharge in time. Then the pit is difficult to immerse by plating solution, resulting in less Zn coverage at the inner surface of the micro-pit. During the nickel plating process, the gas in some deep micro-pits cannot be all eliminated in time when the substrate is immersed in the nickel plating solution. Thus, no nickel plating reaction occurs in the micro-pits, resulting in the void formation in the micro-pits. The pit type defects are finally formed on the plating surface. |
| Key words: aluminum alloy disk intermetallic compound electroless nickel plating wettability microstructure defect |
