ABSTRACT

The aim of the present work is to study the effects of multi-walled carbon nanotubes (MWCNT) concentration and current density on the surface morphology, microhardness, and corrosion resistance of pulsed electrodeposited Ni-P-MWCNT composite coatings. Ni-P-MWCNT composite coatings were deposited on low-carbon steel substrates using different MWCNT concentrations, namely 0.5, 1.0, and 1.5 g L⁻¹ under various current densities of 3, 4, and 5 A dm⁻². The as-produced coatings were characterised using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Vickers microhardness measurement, and electrochemical impedance spectroscopy (EIS). To determine the impact of post-heat treatment on the microstructure and microhardness of the coatings, the composite coatings were heat-treated at 400°C for 1 h. Change in the studied variables profoundly altered the final characteristics of the Ni-P deposits. While the incorporation of 1.0 g L⁻¹ MWCNT enhanced the microhardness of the alloy deposit by 560 HV, the microhardness of the composite coating was further increased by 405 HV when it underwent post deposition-heat treatment. The corrosion resistance of the composite coating is about 4 times higher than that of alloy deposits. The optimum mechano-corrosion results were obtained for Ni-P-1.0 g L⁻¹ MWCNT coating fabricated under current density of 4 A dm⁻².

摘要

本工作的目的是研究多壁碳纳米管 (MWCNT) 浓度和电流密度对脉冲电沉积 Ni-P-MWCNT 复合涂层的表面形貌、显微硬度和耐腐蚀性的影响。在 3、4 和 5 A dm ^-2的各种电流密度下，使用不同的 MWCNT 浓度，即 0.5、1.0 和 1.5 g L ^{-1将 Ni-P-MWCNT 复合涂层沉积在低碳钢基材上}. 使用场发射扫描电子显微镜 (FE-SEM)、X 射线衍射 (XRD)、维氏显微硬度测量和电化学阻抗谱 (EIS) 对所生产的涂层进行表征。为了确定后热处理对涂层微观结构和显微硬度的影响，复合涂层在 400°C 下热处理 1 小时。所研究变量的变化深刻地改变了 Ni-P 矿床的最终特征。而掺入1.0 g L ^-1多壁碳纳米管使合金镀层的显微硬度提高了560 HV，复合涂层的显微硬度在经过沉积后热处理后进一步提高了405 HV。复合镀层的耐腐蚀性比合金镀层高约4倍。^{在4 A dm -2电流密度下制备的Ni-P-1.0 g L -1} MWCNT涂层获得了最佳的机械腐蚀结果。