Purpose

The ability to produce a uniform composition, high corrosion resistance with a hard coating layer during the electroless coating techniques are mainly based on the plating bath composition. The complexing agent is one of the most important components that control the coating layer properties. This paper aims to investigate the effect of the glycine as a complex agent on the surface and corrosion properties of Ni-P and Ni-P/Al₂O₃ electroless coating.

Design/methodology/approach

In this study, the effect of glycine as a complexing agent on the final surface and corrosion properties of the Ni-P and Ni-P/Al₂O₃ coatings has been investigated. The surface morphology and composition of the coated samples were investigated by scanning electron microscope (SEM) imaging and energy dispersive x-ray spectroscopy (EDS) analysis. Linear polarization scan and electrochemical impedance spectroscopy techniques were used to investigate the corrosion properties of the coating layer.

Findings

The results clarify that, glycine has a remarkable effect on the porosity content of Ni-P and Ni-P/Al₂O₃. It was found that increasing of glycine concentration results in higher porosity content in the coating layers. Also, the porosity in the coating layers minimizes the protectability of the coating against corrosion. The results also show that adding nano-alumina (Al₂O₃) to the coating path has improved the corrosion properties by decreasing the porosity in the coating layer. The scanning electron microscope (SEM) images showed that the concentration of glycine affects the content and distribution of alumina nanoparticles embedded in the coating layer. Also, it was observed that using a high concentration of glycine (0.4 M glycine), the alumina tends to agglomerate and the final alumina content in the coating was decreased.

Originality/value

The present study reveals that the quality of the final coating plays a major role in the corrosion performance of the steel substrate. The coating quality can by improve remarkably by optimization of the complexing agent used in the plating bath, to minimize the porosity involve in the coating layer.

中文翻译：

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甘氨酸作为络合剂对Ni-P和Ni-P / Al2O3化学镀层表面和腐蚀性能的影响

目的

在化学镀覆技术中产生具有硬涂层的均匀组成，高耐腐蚀性的能力主要基于镀浴组成。络合剂是控制涂层性能的最重要成分之一。本文旨在研究甘氨酸作为复合剂对Ni-P和Ni-P / Al ₂ O ₃化学镀层的表面和腐蚀性能的影响。

设计/方法/方法

在这项研究中，研究了甘氨酸作为络合剂对Ni-P和Ni-P / Al ₂ O ₃涂层的最终表面和腐蚀性能的影响。通过扫描电子显微镜（SEM）成像和能量色散X射线光谱（EDS）分析研究了涂层样品的表面形态和组成。线性极化扫描和电化学阻抗光谱技术用于研究涂层的腐蚀性能。

发现

结果表明，甘氨酸对Ni-P和Ni-P / Al ₂ O ₃的孔隙率具有显着影响。发现甘氨酸浓度的增加导致涂层中更高的孔隙率含量。而且，涂层中的孔隙率使涂层的防腐蚀能力最小化。结果还表明，添加纳米氧化铝（Al ₂ O ₃到涂层路径）通过降低涂层中的孔隙率改善了腐蚀性能。扫描电子显微镜（SEM）图像显示，甘氨酸的浓度会影响包埋在涂层中的氧化铝纳米颗粒的含量和分布。而且，观察到使用高浓度的甘氨酸（0.4M甘氨酸），氧化铝趋于附聚并且涂层中的最终氧化铝含量降低。

创意/价值

本研究表明，最终涂层的质量在钢基材的腐蚀性能中起着重要作用。通过优化镀浴中使用的络合剂，可以最大程度地提高涂层质量，以最大程度地减少涂层中的孔隙率。