Plasma electrolytic oxidation of as-cast and heat-treated binary Al-Ni alloys

Cosan, K.A.; Gündüz, K.O.; Tarakçı, Mehmet

doi:10.1016/j.surfcoat.2022.128998

Cited by 8 publications

(3 citation statements)

References 38 publications

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“…The results of a few known studies show that Ni as an alloying element contributes to the formation of PEO coatings with an increased fraction of γ-Al 2 O 3 and decreases the microhardness and thickness of the coatings [18]. The corrosion resistance of the coated samples decreases with an increase in the Ni content in the matrix, while the anti-wear performance of the treated samples is improved [39].…”

Section: Introductionmentioning

confidence: 99%

Plasma Electrolytic Oxidation of Al-Zn-Mg-Ni-Fe “Nikalin” Alloys

Letyagin,

Akopyan,

Sokorev

et al. 2024

Metals

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Ceramic coatings were formed on the surface of as-cast Al5.2Zn1.7Mg0.4Ni0.3Fe and heat-treated Al7.0Zn2.7Mg0.5Ni0.4Fe “nikalin” aluminum alloys by using the plasma electrolytic oxidation (PEO) technique in a silicate–alkaline electrolyte. Uniform coatings containing a minimum number of defects and consisting predominantly of a γ-Al2O3 phase were synthesized on the surface of both Al-Zn-Mg-Ni-Fe alloys. The coatings had a microhardness of 660–1200 HV, which is 3.5–11 times higher than that of the “bare” as-cast and heat-treated alloy. The coating on the Al5.2Zn1.65Mg0.4Ni0.3Fe alloy had the highest peak hardness, which is probably caused by the lower residual alloying elements Zn and Mg in the coating bulk. As a consequence, the PEO coating with the highest hardness synthesized on the as-cast alloy exhibited a lower wear rate as compared to the heat-treated alloy. The polarization curves in 3.5% NaCl show that the PEO coatings in all cases reduced the corrosion current density and shifted the corrosion potential toward positive values, thus indicating protective properties of the coatings. The corrosion rate of the as-cast and heat-treated Al-Zn-Mg-Ni-Fe alloys increased noticeably by about 3.7–5.7 times after PEO treatment. A relationship between the residual alloying elements Zn and Mg in the bulk of the PEO coatings and corrosion resistance was established.

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Section: Introductionmentioning

confidence: 99%

Plasma Electrolytic Oxidation of Al-Zn-Mg-Ni-Fe “Nikalin” Alloys

Letyagin,

Akopyan,

Sokorev

et al. 2024

Metals

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“…Al-Ni alloys, which present a eutectic at 639.9 ° C, are currently considered suitable candidates for use in high temperature services [4][5][6]. The adequate performance of the Al-Ni system at high temperatures has been associated with the presence of Al3Ni intermetallic particles resistant in high temperature environments [2,3,5,7].…”

Section: Introductionmentioning

confidence: 99%

Corrosion Susceptibility and Microhardness of Al-Ni Alloys with Different Grain Structures

Román,

Ibañez,

Zadorozne

et al. 2023

Preprint

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The development of Al-Ni alloys with a controlled microstructure has had a great impact on the field of study of aluminum-based alloys. In the present research, the influence of thermal parameters on the grain structures resulting from the directional solidification process of Al-Ni alloys with different alloy content has been studied. It has also been evaluated how different structures and the distribution of second phases influence the corrosion behavior and microhardness of alloys. The columnar-to-equiaxed transition (CET) was observed to occur when the temperature gradient in the melt decreased to values between 1.3 to 2.9 ° C/cm. In addition, a small increase in the microhardness values was observed as a function of the Ni-content. When the Ni-content increase, the resistance to polarization decreases for samples with equiaxed grain structure, throughout the range of compositions studied. Furthermore, the equiaxed grain structure presents higher resistance to polarization values than the columnar grain zone, for alloys with a composition equal to or lower than the eutectic composition.

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“…At the same time, the composition of the substrate used has a significant effect on the properties of PEO coatings. In this work, a systematic study on the individual effects of Si [22][23][24], Cu [25,26], Mg [27], Sn [28], Zn [29], Ce [30], Mn [31], and Ni [32] on the PEO behavior of binary Al alloys in silicate-alkaline electrolytes is reported. We show that the main structural components of PEO coatings on aluminum alloys are α-Al 2 O 3 , γ-Al 2 O 3 , and silicon oxide (mullite).…”

Section: Introductionmentioning

confidence: 99%

The Characterization of Coatings Formed on As-Cast Al, Al–Si, and Al–Ca Aluminum Substrates by Plasma Electrolytic Oxidation

Letyagin,

Akopyan,

Sokorev

et al. 2023

Metals

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In this study, ceramic coatings were grown on the surface of as-cast aluminum alloys via plasma electrolytic oxidation (PEO). The effect of the Si- and Ca-alloying elements in aluminum on the growth process, morphology, composition, mechanical, and corrosion properties of the PEO coatings was investigated. Uniform coatings with a minimum number of defects were formed on the surfaces of Al–Ca alloys. Increasing the Si content in Al led to an increase in the bulk and surface porosity of the coatings. The α-Al2O3 phase mainly formed in the coatings synthesized on pure Al and Al–Ca alloys, while an increased amount of Si in Al alloys hindered the formation of the α-Al2O3 phase. The coatings had a microhardness of 660–1180 HV, which was 20–30 times higher than that of the original as-cast alloy. Moreover, the coating on the Al–Ca alloys had the highest peak hardness, which was probably caused by the formation of a greater amount of the α-Al2O3 phase. Electrochemical studies in 3.5% NaCl have shown that PEO coatings reduce the corrosion current density. Of all PEO-treated alloys, Al and Al1Ca have the lowest corrosion current density and hence the highest corrosion resistance due to the composition and uniformity of the coating.

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Plasma electrolytic oxidation of as-cast and heat-treated binary Al-Ni alloys

Cited by 8 publications

References 38 publications

Plasma Electrolytic Oxidation of Al-Zn-Mg-Ni-Fe “Nikalin” Alloys

Plasma Electrolytic Oxidation of Al-Zn-Mg-Ni-Fe “Nikalin” Alloys

Corrosion Susceptibility and Microhardness of Al-Ni Alloys with Different Grain Structures

The Characterization of Coatings Formed on As-Cast Al, Al–Si, and Al–Ca Aluminum Substrates by Plasma Electrolytic Oxidation

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