High densification and anti-corrosion of graphene-coated aluminum coating deposited on AZ31B magnesium by low-pressure c
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Carbon Letters https://doi.org/10.1007/s42823-020-00128-y
ORIGINAL ARTICLE
High densification and anti‑corrosion of graphene‑coated aluminum coating deposited on AZ31B magnesium by low‑pressure cold spray Liuyan Zhang1 · Xiujin Wang1 · Huishu Wu1 · Yongjin Mai1 · Cansen Liu1 · Xiaohua Jie1 Received: 16 September 2019 / Revised: 1 January 2020 / Accepted: 30 January 2020 © Korean Carbon Society 2020
Abstract In this paper, graphene-coated Al powders prepared by in situ reduction method were directly used for cold spraying, obtaining a graphene-reinforced Al matrix composite coating with more compact structure and better performance. Cross-sectional analysis revealed that compared with the pure Al powders, the graphene-coated Al powders were more severely deformed, and the resulting coating was denser and its porosity was reduced by over 80%. The hardness of the graphene-coated Al coating was increased by 40%, and its brine immersion time was prolonged by nearly three times. However, the graphene increases the pitting sensitivity of the Al coating; so, the enhanced corrosion resistance of the graphene-coated Al coating is mainly attributed to the improvement of its structure densification. Keywords Composites · Metals · Electrochemical measurements · Raman spectroscopy · Surface properties
1 Introduction Due to its special structure, electrical, mechanical, and thermal properties, graphene has been used to reinforce the properties of metal matrix composites (MMC) such as antifriction, thermal conductivity, compressive strength, elasticity, and hardness [1–4]. But its corrosion resistance is rarely reported. The graphene has chemical inertness/stability [5], which is similar to carbon nanotube, and potentially can help in forming a passive layer on the MMC [6]. The uniform dispersion of graphene in MMC is a key issue. Some methods have been tried. Ball milling of graphene with metallic powders is a common method [1, 7–10], but it generally takes a long time, breaks particles, and modifies particle shape. Direct electrostatic adsorption can mix graphene oxide (GO) with metal powders, but a subsequent heating should be conducted to reduce GO to graphene [3]. Compared to these methods, in situ reduction
* Liuyan Zhang [email protected] Xiaohua Jie [email protected] 1
School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, People’s Republic of China
reaction method is an efficient method for rapidly preparing aluminum powders coated with graphene [2, 11]. The MMC preparing methods mainly contain powder metallurgy, electrochemical/chemical deposition, melting and solidification, and thermal/cold spraying [6]. Cold spraying is a technique to accelerate and deposit the solid powders onto the substrate surface at a lower temperature to form a MMC coating [12]. And it is especially suitable for magnesium alloy protection. The corrosion resistance or wear resistance of the cold-sprayed Al-based composite coatings has been reported [13–15]. Yin et al. found that cold spraying could fabr
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