Tribological and corrosion behavior of PEO coatings with graphite nanoparticles on AZ91 and AZ80 magnesium alloys

Pezzato, Luca; Angelini, Valerio; Brunelli, Katya; Martini, Carla; Dabalà, Manuele

doi:10.1016/s1003-6326(18)64659-x

Cited by 61 publications

(19 citation statements)

References 28 publications

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“…This fact is due to the particular mechanism of formation of PEO coatings that permit the formation not only of the substrate oxide but also of compounds coming from the electrolyte . In this case, sodium silicates and phosphate were present in the electrolyte, so the composition of the coating resulted in accordance with the one of the electrolyte and also with the ones previously reported in literature . Mg peaks can also be found in the spectra due to the reflection from the substrate.…”

Section: Resultssupporting

confidence: 88%

“…[13] In this case, sodium silicates and phosphate were present in the electrolyte, so the composition of the coating resulted in accordance with the one of the electrolyte and also with the ones previously reported in literature. [14][15][16] Mg peaks can also be found in the spectra due to the reflection from the substrate.…”

Section: Microstructural Characterizationmentioning

confidence: 99%

“…However, generally a sealing treatment is necessary in order to ensure sufficient resistance against corrosion . Different types of sealing treatments were performed in literature: with particles in order to give also particular properties to the coating, with rare‐earth based conversion layers, and also with compounds that can ensure active protection . However, due to the economical and practical reasons, linked also with the fact that are the ones used in traditional anodizing, the sealing treatments in boiling water remain the ones mainly used in the industrial world.…”

Section: Introductionmentioning

confidence: 99%

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Corrosion and mechanical properties of plasma electrolytic oxidation‐coated AZ80 magnesium alloy

Pezzato

Coelho

Bertolini

et al. 2019

Materials & Corrosion

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Plasma electrolytic oxidation (PEO) coatings were produced on AZ80 magnesium alloy in a solution containing silicates and phosphates and working at high current densities with short treatment times. The effect of a sealing treatment in boiling water on corrosion and mechanical properties of the coatings were investigated. Moreover, the corrosion mechanism of the samples with and without the sealing treatment was evaluated. The microstructure of the coatings was characterized with scanning electron microscope observation and X‐ray diffraction analysis. The mechanical properties were evaluated with nanoindentation tests and the corrosion resistance was studied by potentiodynamic polarization, electrochemical impedance spectroscopy, and scanning vibrating electrode technique. The results showed that the sealing did not influence the microstructure and the mechanical properties of the samples and instead produced a remarkable increase in the corrosion resistance. The crevice corrosion, present in the sample without the sealing, was avoided with the treatment in boiling water.

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Section: Resultssupporting

confidence: 88%

Section: Microstructural Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Corrosion and mechanical properties of plasma electrolytic oxidation‐coated AZ80 magnesium alloy

Pezzato

Coelho

Bertolini

et al. 2019

Materials & Corrosion

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“…Belmonte et al [16] proposed a conclusion that graphene/composite displayed an excellent wear resistance and a small friction coefficient due to the lubricity of graphene, owing to the effect of graphene nanofillers on the tribological performance of ceramic coatings. Pezzato et al [17] and Lv et al [18] found graphite with nanometer structure tending to be absorbed on the surface of the coating and embedded into the pores.As discussed above, some studies on the corrosion-and wear-resistance of the PEO coatings with graphene on magnesium and titanium alloys have been performed [19,20]. However, the study on aluminum alloys is lacking, especially for D16T aluminum alloys using as drill pipe.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Corrosion and Wear Behavior of PEO Coatings on D16T Aluminum Alloy with Different Concentrations of Graphene

Liu

Liao

et al. 2020

Coatings

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The effect of added graphene concentration on the microstructure, phase composition, corrosion-and wear-resistance of plasma electrolyte oxidation (PEO) coatings formed on D16T aluminum alloy in silicate electrolyte with different concentrations of graphene were investigated. The results show that the morphologies of the coatings with graphene were obviously different ascribed to the mode of graphene incorporated into the coating. The coatings consisted of mainly α-Al 2 O 3 , γ-Al 2 O 3 , and Al, which were divided into an outer porous layer and a dense inner layer. The thickness of the coatings increased non-linearly with graphene concentration. The corrosion resistance of the coatings with graphene was significantly improved. The wear resistance of the coatings was also greatly improved apart from the coating with 3 g/L graphene. The coating produced in the electrolyte with 2 g/L graphene exhibited the optimal comprehensive properties because graphene successfully incorporated into the coating via the pores and spread on the surface of the coating.Coatings 2020, 10, 249 2 of 20 are influenced by various process parameters such as the constituent and concentration of electrolytes, oxidation time, substrate, various electrical parameters, and additives [7,8]. The constituent and concentration of the additive play an important role in changing the structure, morphology, wear-and corrosion-resistance of the coatings among those factors. A large number of works about the PEO coatings incorporated particles or powders like TiO 2 [9], ZrO 2 [10], Fe micrograins [11], α-Al 2 O 3 [8], and so on were performed. Zhao et al. [7] studied the effect of graphene oxide on the corrosion resistance of the PEO coating on AZ31 magnesium alloy, and reported that the incorporated graphene oxide markedly decreased micropores and improved the corrosion resistance of AZ31 magnesium alloy. Sarbishei et al. [12] reported that alumina nanoparticles incorporated into the PEO coatings formed on a titanium substrate, reducing the density of the coating and the pores' size. The corrosion resistance was improved with the increase of the alumina concentration, and the coatings formed in the electrolyte with 10 g/L alumina nanoparticles showed the best properties. Fatimah [13] studied the structure and corrosion properties of the coatings formed on 6061 Al alloy through the dual incorporation of SiO 2 and ZrO 2 nanoparticles into the oxide layer and found the coatings with SiO 2 and ZrO 2 displaying the best corrosion resistance because they were used as micropores blocker and cracks filler. Yazdanl et al. [14] studied the tribological performance of graphene/carbon nanotube hybrid reinforced Al 2 O 3 , and it was determined that the coating with graphene nanoplatelets hybrid reinforced Al 2 O 3 composites displayed the best wear resistance. Hvizdos et al. [15] studied the tribological properties of Si 3 N 4 -graphene nanocomposites, and Si 3 N 4 -graphene nanocomposites owned better wear resistance was also confirmed. Belmonte et al. [16] pro...

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Corrosion and Wear Resistance of Micro‐Arc Oxidation Composite Coatings on Magnesium Alloy AZ31—The Influence of Inclusions of Carbon Spheres

Xiao

Fan

et al. 2019

Adv Eng Mater

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Poor corrosion and wear resistance of magnesium (Mg) alloys restrict their applications. Herein, corrosion and wear‐resistant films are formed upon Mg alloy AZ31 through a micro‐arc oxidation (MAO) process in silicate electrolyte in the presence of carbon spheres (CS). Surface morphology, chemical composition, corrosion resistance, hardness, and coefficient of friction (CoF) of the MAO coatings are investigated using field‐emission scanning electron microscopy (FE‐SEM), Fourier transform infrared spectrometry (FTIR), X‐ray diffractometer (XRD), X‐ray photoelectron spectroscopy (XPS), electrochemical and hydrogen evolution measurements, automatic micro‐hardness testing, and reciprocating tribometer, respectively. Results demonstrate that the surface morphology and hardness of MAO coatings vary with the concentration of CS. The presence of CS results in an increased coating thickness from 8.0 ± 1.8 to 12.2 ± 1.8 μm, mean pore size from 0.7 ± 0.1 to 1.9 ± 0.1 μm, open porosity of MAO coating from 4.2 ± 0.4 to 5.6% ± 1.1%, and coating hardness from 347.0 ± 59.0 to 853.0 ± 67.3 Vickers‐hardness (HV). Furthermore, CS‐modified MAO coatings lead to improved corrosion resistance in comparison with that of the neat MAO counterparts. Moreover, the high hardness and formation of SiC of CS‐modified coatings lead to a low and stabilized CoF, which implies an enhanced wear resistance.

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Tribological and corrosion behavior of PEO coatings with graphite nanoparticles on AZ91 and AZ80 magnesium alloys

Cited by 61 publications

References 28 publications

Corrosion and mechanical properties of plasma electrolytic oxidation‐coated AZ80 magnesium alloy

Corrosion and mechanical properties of plasma electrolytic oxidation‐coated AZ80 magnesium alloy

Corrosion and Wear Behavior of PEO Coatings on D16T Aluminum Alloy with Different Concentrations of Graphene

Corrosion and Wear Resistance of Micro‐Arc Oxidation Composite Coatings on Magnesium Alloy AZ31—The Influence of Inclusions of Carbon Spheres

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