Effect of current density and electrolyte pH on microstructure of Mn–Cu electroplated coatings
Effect of current density and electrolyte pH on microstructure of Mn–Cu electroplated coatings
复制标题
DOI：
10.1016/j.apsusc.2013.07.049
复制
发表时间：
2013-11
影响因子：
6.7
通讯作者：
M. Haerifar;M. Zandrahimi
中科院分区：
文献类型：
--
作者：
M. Haerifar;M. Zandrahimi
在本研究中，304不锈钢（SS）电镀纳米晶Mn-Cu合金镀层从含有硫酸铵的浴。采用动电位扫描和恒电流实验对Mn-Cu电沉积膜进行了电化学研究。通过扫描电子显微镜（SEM）、增重测量、X射线衍射（XRD）和能量色散X射线能谱（EDS）分别表征了pH和电流密度对沉积物的微观结构、阴极效率、晶体结构和化学组成的影响。结果表明：低电流密度下获得的Mn-Cu镀层中含有大量的Cu，且镀层组织不均匀;而高电流密度下获得的Mn-Cu镀层中含有少量的Cu，且镀层均匀、致密、呈非晶态。薄膜的XRD和SEM分析表明，Mn-Cu合金的沉积受电流密度的影响比电解液pH值。然而，结果并没有显示任何特定的变化，在晶粒尺寸的涂层与电流密度的变化。结果表明，Cu的共沉积延缓了沉积态韧性γ-Mn向硬脆α-Mn的相变。
In the present study 304 stainless steel (SS) was electrochemically plated with nanocrystalline Mn–Cu alloy coatings from a bath containing ammonium sulfate. The electrochemical investigation of Mn–Cu electrodeposited films was managed by potentiodynamic scans and galvanostatic experiments. The effect of pH and current density on the microstructure, cathodic efficiency, crystallographic structure, and chemical composition of the deposits were characterized by means of scanning electron microscopy (SEM), weight gain measurements, X-ray diffraction (XRD), and energy dispersive X-ray spectrometry (EDS), respectively. The results showed that Mn–Cu coatings obtained at low current density contain a large amount of Cu and a heterogeneous microstructure, while at high current density uniform, compact, and amorphous coatings with a small amount of Cu was obtained. The XRD and SEM analyses of the films showed that the deposition of Mn–Cu alloy is more affected by the current density than electrolyte pH. However, the results did not show any specific changes in the grain size of the coatings with variation of current densities. The results indicated that Cu co-deposition delayed the phase transformation of as-deposited ductile γ-Mn to the brittle and hard α-Mn.