光亮剂对化学镀镍层性能及结构的影响

Effect of Brighteners on Structure and Performance of Electroless Nickel Coatings

摘要:

研究了酸性化学镀镍溶液的贵金属离子、重金属离子光亮剂对镀层硬度、结合力、孔隙率以及耐蚀性的影响,并通过AFM,XRD和XPS,分析光亮剂对镀层组织结构的影响。结果表明:贵金属离子光亮剂能明显提高EN镀层的耐蚀性,而重金属离子光亮剂降低了EN镀层的耐蚀性;两种光亮剂都能降低镀层的表面粗糙度,使构成镀层胞状物变小,并使镀层的非晶结构更加明显,镀态镀层表面Ni以Ni原子和Ni2+离子形式存在,P以负价离子和PO43-离子的形式存在,光亮剂的加入利于镀层表面形成磷酸镍的保护膜。

Abstract:

The effect of the noble and heavy metal ion brighteners in acidic electroless nickel solution on properties of coatings including hardness, bonding force, porosity and corrosion resistance were investigated. These brighteners play a dominant role in coating structure from the measurements of AFM, XRD and XPS. The results show that the noble metal ion brighteners can greatly improve the electroless nickel coating performance, for example, reducing the surface coarseness and making the layer column smaller. Moreover, the amorphous structure get more remarkable due to presence of noble and heavy metal ion brighteners. XPS results reveal that Ni element exists in the form of Ni0 and Ni2+, while P exists in the form of negative ion and PO43-. So the brighteners are propitious to form protective film of Ni3(PO4)2.