Phosphating passivation of vacuum evaporated Al/NdFeB magnets boosting high anti-corrosion performances

Chen, Jing; Yang, Hongyi; Xu, Guangqing; Zhang, Pengjie; Lv, Jun; Sun, Wei; Li, Bingshan; Huang, Jun; Wang, Dongmei; Wu, Yucheng

doi:10.1016/j.surfcoat.2020.126115

Cited by 20 publications

(7 citation statements)

References 39 publications

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“…Furthermore, the high-resolution P 2p spectrum of the Al substrate surface confirmed the existence of P–O–Al (133.4 eV), PO (134.2 eV), P–O–Mg (134.8 eV), and P–O–Al (135.3 eV) (Figure e). Compared with the Figure b,c, the new appeared peaks at 533.4 and 135.3 eV were assigned to the P–O adsorption of the cross-linked phosphate networks (CP&MgO-AOP) on the Al substrate surface (Figure d,e) . The changes in the chemical environment of the Al element result in the chemical shift of the P–O–Al bonding.…”

Section: Resultsmentioning

confidence: 89%

Robust Waterborne Superhydrophobic Coatings with Reinforced Composite Interfaces

Lin

Zhang

Yuan

et al. 2020

ACS Appl. Mater. Interfaces

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Waterborne superhydrophobic coatings have attracted tremendous attention recently, but their practical applications are severely limited by hydrophobic instability and poor mechanical durability. Herein, a novel robust waterborne PTFE-CP&MgO-AOP superhydrophobic coating was successfully fabricated by reinforcing composite interfaces. Combined with the self-polymerization of dopamine and the in situ grown MgO, CNTs-polydopamine&MgO (CP&MgO) particles with improved interfacial compatibility were obtained. Through the cross-linking and hydrogen bonding interactions, phosphate networks (CP&MgO-AOP) with the aluminum orthophosphate (AOP) binder were formed during dehydration polymerization. The phosphate networks not only enhanced the interfacial interaction among CP&MgO to form coral-like structures but also strengthened the interfacial binding force between the waterborne polytetrafluoroethylene (PTFE) coating and the substrate. With the enhanced composite interfacial strength, the waterborne PTFE-CP&MgO-AOP coating exhibited excellent wear-resistance, which can withstand more than 1.27 × 105 abrasion cycles. Moreover, the chemical bonding between the functional groups of phosphate networks and metal substrate improved the adhesion strength from grade 5 to 1. Furthermore, the prepared coating surface with the reticular/coral-like composite structures can lock the stable gas layer to maintain excellent hydrophobic stability, even under the conditions of strong acidic/alkaline, high-temperature, xenon lamp irradiation, and mechanical wear. Thus, this study is expected to open new insights into interfacial enhancement of robust waterborne superhydrophobic coatings.

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Section: Resultsmentioning

confidence: 89%

Robust Waterborne Superhydrophobic Coatings with Reinforced Composite Interfaces

Lin

Zhang

Yuan

et al. 2020

ACS Appl. Mater. Interfaces

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“…This is mainly because the corrosion products with a certain thickness are generated on the surface [34], which greatly hinders the diffusion of ions and results in a sharp decrease in the corrosion rate (seen in Figure 3g). At the middle and late stages of corrosion (4-5 d), the R p of the Q235 steel decreased to 53.10 Ω•cm 2 for 4 d and 58.84 Ω•cm 2 for 5 d. It may be that the morphology and structure of the corrosion products changed with the progress of the corrosion [18,35]. At the same time, part of the surface cracked leading to the intrusion of corrosive ions into the matrix, causing the corrosion to continue (Seen Figure 3j-m) [18].…”

Section: Corrosion Ratementioning

confidence: 97%

“…At the middle and late stages of corrosion (4-5 d), the R p of the Q235 steel decreased to 53.10 Ω•cm 2 for 4 d and 58.84 Ω•cm 2 for 5 d. It may be that the morphology and structure of the corrosion products changed with the progress of the corrosion [18,35]. At the same time, part of the surface cracked leading to the intrusion of corrosive ions into the matrix, causing the corrosion to continue (Seen Figure 3j-m) [18]. The relationship between the corrosion rate and the corrosion current density in Table 3 is shown in Equation ( 2) [36].…”

Section: Corrosion Ratementioning

confidence: 97%

“…Onyeachu et al (2020) [17] found that the exposure time has positive effects in enhancing the corrosion resistance and efficiency of 2-(2-pyridyl) benzimidazole. Chen et al (2020) [18] studied the corrosion processes and corrosion mechanisms of the samples during the immersion test in 3.5 mass% NaCl solution at different time intervals. Rodrigues et al (2020) [19] parameterized the sintering times, which aided in evaluating the effect of the intermetallic compound formed on the microstructural array.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Corrosion Time on the Synergistic Corrosion of Q235 Steel in Sodium Aluminate Solutions

Quan

Chen

2021

Metals

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During Bayer alumina production with high-sulfur bauxite, the sulfide ions in the sodium aluminate solution caused serious corrosion to Q235 steel, which is the material of the tank equipment. This study investigates the effect of corrosion time on Q235 steel synergistic corrosion in sodium aluminate solution using the weight-loss method and electrochemical measurements. The results indicate that the corrosion rate decreases sharply, the rate equation satisfies the mathematical model of power function at the initial stage of corrosion, and the transformation of unstable iron sulfide to stable iron oxide at the later stage results in the decrease in sulfur content in the corrosion products and surface pseudo-passivation. There are two main types of corrosion products, as follows: one is the octahedral crystal particle, which is composed of Fe2O3, Fe3O4, Al2O3 and NaFeO2, and the other is the interlayer corrosion between the surface layer and the matrix, which is composed of FeS, FeS2 and MnS2. At day 3, the dynamics of the Q235 steel electrode is controlled by charge transfer and ion diffusion. However, at other times the dynamics are mainly controlled by charge transfer.

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“…As an environment friendly technique, PVD including evaporation [16], ion vapour deposition (IVD) [17], and magnetron sputtering have been applied in industry [18,19]. Al coatings prepared by PVD are suitable for corrosion protection [20,21] and do not change the magnetic properties of the magnet [22,23]. However, the coating prepared by evaporation always exhibit defects in the form of micropores, whereas the coating prepared through IVD tend to exhibit large granulated inclusions and columnar structures, which could lead to perpendicular gaps [24].…”

Section: Introductionmentioning

confidence: 99%

Microstructures of Al coatings prepared through magnetron co-sputtering with microcrystalline Ti doping

Zhang

Cui

Wang

et al. 2022

J. Phys.: Conf. Ser.

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Sintered NdFeB magnets are being utilised in numerous applications because of the excellent magnetic properties. However, due to its main components are Fe, B and rare earth metals. There is a potential difference between the neodymium rich phase, boron rich phase and the main phase, which was very easy to form a primary battery and cause electrochemical corrosion on the surface of the material. After the materials are easy to be corroded or the components and structures change, the performance of the materials will become weak or even lost, which will affect the service performance and life of the devices or equipment. According to the requirements of surface protection technology for NdFeB magnets, the preparation of protective coating by magnetron sputtering was an efficient means to enhance the corrosion resistance of magnets. Pure Al coating was deficient in microstructure, hardness and corrosion resistance, and the preparation of composite coating by doping co-sputtering had become a development trend. In the current work, AlTi coatings with various Ti contents were prepared from an Al target and a Ti target using direct and radio frequency hybrid magnetron co-sputtering. The surface morphology, microstructure, and elemental compositions of the AlTi coatings were explored through XRD (X-ray diffraction), SEM (scanning electron microscopy), and EDS (energy dispersive spectroscopy). The anticorrosion performances of the AlTi coatings were evaluated by performing electrochemical tests. According to SEM and EDS, the AlTi composite coating was denser and more homogeneous than that of the Al single layer. Furthermore, the results demonstrated that microcrystalline Ti doping reduced the grain size of Al coatings. Therefore, the corrosion current density of the sintered NdFeB magnets plated with Al(120w)/Ti(10w) was approximately more than a hundred times inferior to that of the pure Al layer, and the hardness of AlTi composite coatings also improved.

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Phosphating passivation of vacuum evaporated Al/NdFeB magnets boosting high anti-corrosion performances

Cited by 20 publications

References 39 publications

Robust Waterborne Superhydrophobic Coatings with Reinforced Composite Interfaces

Robust Waterborne Superhydrophobic Coatings with Reinforced Composite Interfaces

Effect of Corrosion Time on the Synergistic Corrosion of Q235 Steel in Sodium Aluminate Solutions

Microstructures of Al coatings prepared through magnetron co-sputtering with microcrystalline Ti doping

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