Crystalline and amorphous PEO based ceramic coatings on AA6061: Nanoindentation and corrosion studies

Pillai, Anju M.; Ghosh, Rabindra; Dey, Arjun; Prajwal, Kumar; Rajendra, A.; Sharma, Anand; Sampath, S.

doi:10.1016/j.ceramint.2021.01.147

Cited by 30 publications

(4 citation statements)

References 42 publications

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“…First of all, the coating produced on the as printed sample was the one characterized by the higher amorphous phase, as evidenced by XRD in Fig. 12 , and this induces an increase in the mechanical properties, as evidenced by Pillai et al 48 . Secondly, as evidenced by the SEM observations of both the surfaces and the cross sections, the coatings produced on the as printed and the annealed samples were thicker and denser, thus leading to higher hardness values in comparison to the ones obtained on the cast and the solution treated samples.…”

Section: Resultsmentioning

confidence: 86%

Influence of silicon morphology on direct current plasma electrolytic oxidation process in AlSi10Mg alloy produced with laser powder bed fusion

Pezzato

Gennari

Franceschi

et al. 2022

Sci Rep

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In this work, plasma electrolytic oxidation (PEO) process was applied on AlSi10Mg samples, produced with laser powder bed fusion (L-PBF), in the as printed condition and after different heat treatments, and, for comparison, on as-cast samples of AlSi10Mg. PEO process was performed in direct-current mode using high current densities and short time in a basic silicate electrolyte. For the first time, the effects of silicon morphology in L-PBF AlSi10Mg samples, in as printed condition and after different heat treatments, on the obtained PEO coating were investigated in terms of microstructure and corrosion properties. The microstructure of the substrate was characterized with optical and electron microscopy observations (optical microscopy OM, scanning electron microscopy SEM, and transmission electron microscopy TEM) and with X-ray diffraction (XRD). The analysis showed that heat treatments of annealing and solution treating modified the morphology and distribution of silicon in the samples obtained through L-PBF. The PEO coated samples were characterized with SEM, both on the surface and in the cross-section, and compositional analysis were performed with energy dispersive spectroscopy (EDS) analysis and elemental mapping. The coatings were also analyzed with XRD and the corrosion properties evaluated through electrochemical impedance spectroscopy (EIS) tests. Also microhardness tests were performed on the substrates and on the coatings. The microstructure of the coatings was strongly influenced by the silicon distribution. In particular, a non-uniform distribution of silicon and the presence of iron-rich intermetallic (obtained in the as-cast and solution treated samples) induced the formation of more porous and thinner coatings in comparison with the ones obtained in the as printed and annealed samples. The not-uniform silicon distribution produced a not-homogenous distribution of silicon into the coatings. The particular cellular structure of the as printed sample induced the formation of a coating with a higher amorphous fraction, in comparison with the ones produced on the other samples. The higher thickness and lower porosity of the coatings obtained on the annealed and as printed samples resulted in an increase of the corrosion resistance.

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Section: Resultsmentioning

confidence: 86%

Influence of silicon morphology on direct current plasma electrolytic oxidation process in AlSi10Mg alloy produced with laser powder bed fusion

Pezzato

Gennari

Franceschi

et al. 2022

Sci Rep

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“…The surface morphology of the anodic coating reveals mud-crack-like morphology with numerous irregularities, micro-channels, and grooves [6,7]; hence, multiple nanoindentation experiments (24 numbers) are required to deal with the scatter in the data due to aforesaid microstructural inhomogeneity. The scatter in data in nanomechanical properties was dealt with the application of Weibull distribution for the differently coated materials systems [26][27][28], however the attempt of AI/ML technique to deal scatter in data and further to predict characteristic modulus and harness are yet not attempted in literature. MLP technique of ANN was used for modeling the loading curve, and the Power law model was fitted in the unloading section curve using the least square optimization technique.…”

Section: Materials and Methodologymentioning

confidence: 99%

Artificial neural network-based approach for prediction of nanomechanical properties of anodic coating on additively manufactured Al–10Si–Mg alloy

Ghosh,

Sahu,

Dey

et al. 2024

Modelling Simul. Mater. Sci. Eng.

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Nowadays, anodized coating on additively manufactured (AM) or 3D printed Al-10Si-Mg alloy are used for various components in spacecraft such as antenna feeds, wave guides, structural brackets, collimators, thermal radiators etc. In this study, Artificial Neural Network (ANN) and Power law-based models are developed from experimental nanoindentation data for predicting elastic modulus and hardness of anodized AM Al-10Si-Mg at any desired loads. Data from nanoindentation experiments conducted on plan- and cross-sections of anodized coating on AM Al-10Si-Mg alloy was considered for modelling. Apart from nanomechanical properties, load and displacement curves were predicted using Python software from ANN and the Power law model of nanoindentation. It is observed that the ANN model of 50 mN nanoindentation experimental data can accurately predict the loading pattern at any desired load below 50 mN. Elastic modulus and hardness of anodized AM Al-10Si-Mg computed from ANN and the power law model of the unloading curve are also comparable with the values obtained from Weibull distribution analysis reported elsewhere. The derived models were also used to predict nanomechanical properties at 25 and 35 mN, for which no experimental data was available. The computed hardness of plan section of the anodic coating is 3.99 and 4.02 GPa for 25 and 35 mN, respectively. The computed hardness of cross-section of the anodic coating of is 7.16 and 6.61 GPa for 25 and 35 mN, respectively. Thus, the ANN and Power law model of nanoindentation can predict elastic modulus and hardness at different loads by conducting the minimum number of experiments. The novel approach to predict nanomechanical properties using ANN resulted in determining realistic and design specific data on hardness and modulus of the anodized coating on AM Al-10Si-Mg alloy.

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“…Several studies describe the characterisation of MAO coatings crystallinity. Friable layers are the most studied and contain a majority of gamma alumina, alpha alumina [79][80][81], and some find mullite [82,83], and delta alumina [84]. One study focused on the dense layer exposed by mechanical grinding [85].…”

Section: Composition Of Coatingsmentioning

confidence: 99%

Micro-Arcs Oxidation Layer Formation on Aluminium and Coatings Tribological Properties—A Review

et al. 2023

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This review proposes to carry out a state-of-the-art associated with micro-arc oxidation. Firstly, the different aspects of the growth mechanisms of the oxides are detailed. Then, the formation of micro-arcs and the case of soft-spark treatment are discussed. Then, the electrolytic reactions involved in the layer construction are outlined. We focused on the influence of aluminium alloys on the appearance of the coating and its characteristics before considering the electrolyte formulation. We have concentrated some of our efforts on silicate-based electrolytes, mainly used in research and industry. The importance of electrical parameters in layer formation is detailed later. The main factors studied in the literature are the current source, current density, treatment frequency and duration, and duty cycle. We have also noted the different phase compositions identified in the literature. Finally, since the process is particularly advantageous for protecting the surfaces of aluminium parts against wear, we conclude this review by presenting work on the tribological properties of this coating. In this final section, we highlight the work on the wear-reducing properties and tribological mechanisms identified in the literature. Particular attention is paid to the relationship between the nature of the substrates used, the role of the electrolyte and the counterpart choice on the friction and wear results.

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Crystalline and amorphous PEO based ceramic coatings on AA6061: Nanoindentation and corrosion studies

Cited by 30 publications

References 42 publications

Influence of silicon morphology on direct current plasma electrolytic oxidation process in AlSi10Mg alloy produced with laser powder bed fusion

Influence of silicon morphology on direct current plasma electrolytic oxidation process in AlSi10Mg alloy produced with laser powder bed fusion

Artificial neural network-based approach for prediction of nanomechanical properties of anodic coating on additively manufactured Al–10Si–Mg alloy

Micro-Arcs Oxidation Layer Formation on Aluminium and Coatings Tribological Properties—A Review

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