Microstructure evolution and improved corrosion resistance of electrodeposited NiCo-Al composite coatings with different Al contents

JOURNAL OF ALLOYS AND COMPOUNDS

卷:738

Article

Cai, Fei¹  Cai, Xijun^1,2  Zhang, Shihong^1,2  Jiang, Chuanhai³ 

[1] Anhui Univ Technol, Res Ctr Modern Surface & Interface Engn, Maanshan City 243002, Anhui, Peoples R China

[2] Anhui Univ Technol, Sch Mat Sci & Engn, Maanshan City 243002, Anhui, Peoples R China

[3] Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, 800 Dongchuan Rd, Shanghai 200240, Peoples R China

关键词: Composite coating;    Rietveld while pattern fitting;    Texture;    Corrosion resistance;   

DOI  :  10.1016/j.jallcom.2017.11.335

来源: Elsevier

【 摘 要 】

In current work, pure Ni, NiCo, NiCo/2.9Al and NiCo/5.5Al coatings were fabricated by using electrodepositing method. X-ray diffraction (XRD), Rietveld while pattern fitting (RWPF), transmission electron microscope (TEM), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) experiments in 3.5 wt% NaCl solutions were used to investigate the effects of Al metal particles on the structure evolution and corrosion resistance of the investigated four coatings. Both the RWPF and TEM results showed that alloying with Co significantly decreased the crystallite size. Furthermore, crystallite size was further reduced with the addition of Al micro-particles and smaller XRD crystallite size of 17 nm was obtained for NiCo/5.5Al composite coating. Measured pole figure and fitted pole figure exhibited the fiber texture for all the investigated coatings and addition of Co and Al suppressed the (200) texture of pure Ni coating and promoted the random orientation for the NiCo and NiCo-Al composite coating. Corrosion experiment results showed that, compared with Ni and NiCo coatings, addition of Al micro-particle could significantly increase the corrosion resistance. The NiCo/5.5Al composite coating exhibited the smaller corrosion current density of 0.581 mu A/cm(2). (c) 2017 Elsevier B.V. All rights reserved.

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