添加剂对脉冲电沉积纳米晶锌镀层性能的影响

Influence of Organic Additives on the Properties of Pulse-Eelectrodeposited Nanocrystalline Zinc Coating

通过向电镀溶液中加入有机添加剂的方法在硫酸盐体系中制备纳米级锌镀层。采用极化曲线研究了有机物添加剂对锌沉积行为的影响,并用XRD和SEM对镀层结构和形貌进行表征。研究表明,当脉冲导通时间为4ms,关断时间为8ms,脉冲峰值电流密度为2A/cm2时,以苄叉丙酮和硫脲为主光亮剂,含量分别为0.5g/L,可制备出光亮致密的纳米级锌镀层,平均晶粒尺寸为43nm。镀层晶粒细化的主要原因是有机添加剂的加入提高了锌的沉积过电位,使锌晶核的形成速度变快而长大速度变慢。

Nanocrystalline zinc coating was prepared via the pulse-electrodeposition in a sulfate bath containing organic additives.The effect of the organic additives on the electrodeposition behavior of the Zn coating was investigated,based on the measurement of the polarization curves.Moreover,the microstructure and morphology of the Zn coating were analyzed by means of X-ray diffraction and scanning electron microscopy.The results indicated that it was feasible to prepare bright and compact nanocrystalline zinc coating with an average grain size of 43 nm at current-on time of 4 ms,current-off time of 8 ms,and peak current density of 2 A/cm2,when the concentration of the brightening agents thiourea and benzalacetone was kept as 0.5 g/L.The refining of the grains of the Zn coating was mainly attributed to the increase in the overpotential of Zn cathode in the presence of the organic additives,which contributed to promoting the formation and retarding the growing-up of the crystal-cores.