碳纤维无钯化学镀镍前处理工艺

Pretreatment Processing of Electroless Nickel Plating on Carbon Fiber with Palladium-free Activation

传统的碳纤维化学镀镍采用PdCl2-SnCl2前处理,该工艺过程繁多、需消耗大量的贵金属钯且成本高。本研究采用无钯化学镀方法对碳纤维进行化学镀镍前处理。研究了硝酸处理时间对镍镀层的作用关系,表明30min最佳。分析了碳纤维络合吸附Ni2+过程中Ni2+与其增重率的关系,推导了Ni2+吸附过程的动力学方程,吸附反应的平衡常数K=2.525,推导所得曲线与实验曲线基本一致。讨论了反应温度对镀层中P含量的影响,反应温度为80℃时,镀层中P含量达最大值11.42%。通过SEM、DSC、XRD分析对比KBH4-NiSO4无钯前处理法与PdCl2-SnCl2前处理法所得镀层,表明用无钯化学镀方法得到的镍镀层能达到传统镀层的均匀性、紧密性、粘合性、抗氧化性。

Traditional electroless nickel plating on carbon fibers concerns the use of PdCl2-SnCl2 activation pre-treatment,which can be costly and requires extended process lines with high consumption of noble metal palladium. A new pretreatment process of electroless nickel plating on carbon fibers is proposed in this paper,using palladium-free activation. The effects of nitric acid processing time on the quality of nickel coating is studied and the optimal processing time is determined to be 30min. The effects of the concentrations of Ni2＋ on the rate of weight gain during Ni2＋ complexing adsorption process is analyzed,the kinetic equation of the process is established,and the reaction equilibrium constant K is determined as 2.525. The theoretical values calculated by the equation are basically consistent with the experimental data. The effects of the reaction temperature on P content in the Ni-P coating are discussed. P content reaches a maximum value 11.42% at temperature of 80℃. Materials characterizations of the deposited layers are analyzed by SEM,EDX and XRD. The experiment results show that the nickel deposit on carbon fiber obtained by this KBH4-NiSO4 method is as uniform,compact,adhesive and antioxidant as that obtained by conventional electroless nickel plating.