苯基硫脲对6063铝合金表面化学镀镍层电化学性能的影响  

Effect of Phenyl Thiourea as a Stabilizer on the Electrochemical Properties of Electroless Ni-P Coatings on 6063 Aluminum Alloy

作　　者：余会成[1] 韦贻春[1] 韩燕燕[1] 

机构地区：[1]广西民族大学化学化工学院,南宁530006

出　　处：《应用化学》2013年第6期683-689,共7页Chinese Journal of Applied Chemistry

基　　金：广西产业重大科技攻关工程(11107003-2);广西民族大学引进人才科研启动基金(2009QD024)

摘　　要：采用极化曲线及交流阻抗技术研究了不同浓度的苯基硫脲(稳定剂)对6063铝合金表面镍层的电化学性能的影响。极化曲线结果表明,镀液中加入苯基硫脲后的镀镍层比基体铝合金具有更正的腐蚀电位(Ecorr)、小孔(点)腐蚀电位(Epit)及更低的腐蚀电流(icorr)。为了解释镍层的电化学性能,建立了等效电路模型,并拟合出了表面电阻(Rcoat)及电容(Qcoat),电荷转移电阻(Rct)及双电层电容(Qdl)等腐蚀参数。交流阻抗研究结果表明,加入6～10 mg/L苯基硫脲后的镀镍层具有较高的表面电阻(Rcoat)、电荷转移电阻(Rct)及较低的表面电容与双电层电容(Qcoat与Qdl)。镀镍层的交流阻抗谱及极化曲线的测试结果表明,制备的镀层具有较好的耐腐蚀性能,并且相互吻合。采用扫描电子显微镜及能谱对化学镀镍层的表面形貌及成份进行了分析。结果显示,表面处于较均匀的状态,磷元素的质量分数超过10%。Polarization curves and AC impedance spectroscopy were used to investigate the effects of different concentrations of stabilizer phenyl thiourea（PHTU） on the electrochemical properties of electroless Ni-P coatings on a 6063 aluminum alloy. The polarization curves show that the coatings formed in phenyl thiourea-containing electroless nickel solution have a more positive corrosion potential（Ecorr） and pitting corrosion potential（Epit）, and a lower corrosion current density（icorr） than the bare aluminum alloy. To explain the electrochemical properties of the coatings, a simple equivalent circuit is designed. Electrochemical parameters of EIS, such as the surface resistance（Rcoat） and capacitance（Qcoat）, charge transfer resistance（Rct） and double layer capacitance（Qdl）, have been obtained by fitting the EIS plots. The EIS results show that th coatings formed in 6～10 mg/L PHTU electroless nickel solution present a higher resistance（Rcoat and Rct） and lower capacitance（Qcoat and Qdl） values. The EIS and polarization curve results indicate that the prepared coatings have a better corrosion resistance and the EIS and polarization curve results are in agreement with each other. The morphology and composition of the Ni-P coatings have been examined by using a SEM and EDS, respectively. The results show the coating surface is in a uniform state and the mass fraction of P element on the coating surface is more than 10%.

关 键 词：化学镀镍层 铝合金 稳定剂 电化学 腐蚀阻力 

分 类 号：O647[理学—物理化学]