Optimization of plasma electrolyte oxidation process parameters for corrosion resistance of Mg alloy

Shahri, Z.; Allahkaram, Saeed Reza; Soltani, Reza; Jafari, Hassan

doi:10.1016/j.jma.2018.10.001

Cited by 33 publications

(12 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is also worth mentioning that the electrical conductivity for sample C was higher than the others, promoting fine-spark discharges, the formation of a fine-grain structure and more uniform and smoother coatings ( Ref 7,23). Even though the MAO coating formed by the dual electrolyte was the thickest one when compared to the others as shown in Table 3, it was still relatively smooth.…”

Section: Sem Characterization Of the Coatingsmentioning

confidence: 92%

Influence of Electrolyte Compositions and Electrical Parameters on Thermal Properties of Micro-Arc Oxidized AZ91 Alloy

Selvi

Muhaffel

Yürektürk

et al. 2021

J. of Materi Eng and Perform

View full text Add to dashboard Cite

In this study, AZ91 Mg alloy was micro-arc oxidized using different voltages in silicate-and aluminate/ phosphate-based (dual) electrolytes that included K 2 ZrF 6 or Na 2 ZrO 3 as the Zr source for synthesizing ZrO 2 in the micro-arc oxidation (MAO) coatings. Structural characterizations were done by using scanning electron microscopy and x-ray diffraction techniques. MAO coating characteristics of different samples were compared by measuring coating thickness, surface roughness, average pore size, and total pore fraction. Both hardness and pull-off tests were conducted to characterize the mechanical properties of the coatings. Thermal conductivity measurements and thermal shock tests were also carried out to evaluate the effect of the electrolyte composition and the type of Zr containing compound. It was found that the equivalent thermal conductivity of the MAOed samples can be reduced up to 30% compared to the bare AZ91 alloy. The decrease of the thermal conductivity was mainly attributed to formation of a thicker and denser MAO coating, and the incorporation of ZrO 2 phase into the fabricated MAO coating. Finally, increased thermal shock resistance was strongly correlated with a lower hardness and higher cohesive strength of the MAO coating, which also leads to smaller crack formation and spallation-free surface characteristics.

show abstract

Section: Sem Characterization Of the Coatingsmentioning

confidence: 92%

Influence of Electrolyte Compositions and Electrical Parameters on Thermal Properties of Micro-Arc Oxidized AZ91 Alloy

Selvi

Muhaffel

Yürektürk

et al. 2021

J. of Materi Eng and Perform

View full text Add to dashboard Cite

show abstract

“…As seen in Figure 2, the Ra increases with incrementing concentration from 0 to 5 g L −1 , which is also in agreement with the FESEM images. The higher final voltage results in a coarse microstructure [27,28]. Furthermore, the high tendency formation of crater features and granules of oxide compounds increases the surface roughness.…”

Section: Surface Morphology Observation and Roughness Of The Coatingsmentioning

confidence: 99%

Effect of Molybdate on Corrosion Performance of Oxide Coating Produced on 7075 Al Alloy Using PEO

et al. 2022

View full text Add to dashboard Cite

In this research, plasma electrolytic oxidation (PEO) coatings were prepared on 7075 Al alloy in a silicate-based solution with Na2MoO4 additive using a unipolar waveform at constant current density. The coatings displayed micro-pores, micro-cracks, pancake-like and crater-like features, and also solidified molten oxide particles on the surface. The coatings were majorly composed of Al2O3 (γ, δ, and α), SiO2 (amorphous), and MoO3 phases, which confirms the incorporation of molybdenum in the case of additive-containing coatings. Molybdenum species were transported through cracks, channels, and micropores, as the ready access pathways into the coating and partly sealed the coating pores. The EIS technique was used to evaluate the long-term corrosion performance of the coatings up to 168 h of immersion in 3.5 wt.% NaCl solution. The results showed that the barrier action of the PEO coatings was highly enhanced by adding Na2MoO4 due to the higher resistance that alumina achieved to chlorine absorption and also its higher stability by the incorporation of MoO3. The coating formed in the presence of 5 g L−1 Na2MoO4 showed the highest thickness and the lowest porosity percent (15.15%), which provided the highest corrosion performance at long immersion times.

show abstract

“…The diffraction peaks of the second phase in the alloys are weak and difficult to be identified by XRD analysis. Compared with the as-cast alloys, the diffraction intensities of ( 0002), (11)(12)(13)(14)(15)(16)(17)(18)(19)(20), and (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) crystal planes of the α-Mg phase in the ET and HT alloys are enhanced, indicating the textures exist in the alloys after hot extrusion.…”

Section: Microstructurementioning

confidence: 99%

“…Recent studies examining biodegradable magnesium alloys have mainly focused on areas, such as alloying, [11] composite technology, [12,13] additive manufacturing, [14] heat treatment, [15] extrusion treatment, [16] surface modification, [17,18] and so forth. In terms of alloying methods, the alloying elements need to meet biosafety requirements.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of mechanical properties and corrosion resistance of Mg–2Zn–0.5Zr–1.5Dy (mass%) alloy by a combination of heat treatment and hot extrusion

Wen

et al. 2021

Materials & Corrosion

View full text Add to dashboard Cite

To enhance the mechanical properties and poor corrosion resistance of magnesium alloy in vitro, the as‐cast Mg–2Zn–0.5Zr–1.5Dy (mass%) magnesium alloy was subjected to two types of extrusion treatment, one is hot extrusion (denoted as ET alloy), the other is heat treatment followed by hot extrusion (denoted as HE alloy). The microstructure, mechanical properties, and corrosion behaviors of these extruded alloys are assessed. The results show that the HE alloy has superior mechanical properties and a slower corrosion rate than the ET alloy. The yield strength and elongation of the HE alloy reach 287 ± 10 MPa and 17.6 ± 0.5%, respectively, and its corrosion rate is only 0.59 ± 0.16 mm year−1. After hot extrusion, microscale and nanoscale second‐phase exist in the extruded alloys, and the nanoscale second‐phase can improve their mechanical properties by second‐phase strengthening. However, the presence of microscale second phase can cause galvanic corrosion and result in poor corrosion resistance. The HE alloy has good properties due to it containing more nanoscale second‐phase and fewer microscale second‐phase.

show abstract

Optimization of plasma electrolyte oxidation process parameters for corrosion resistance of Mg alloy

Cited by 33 publications

References 36 publications

Influence of Electrolyte Compositions and Electrical Parameters on Thermal Properties of Micro-Arc Oxidized AZ91 Alloy

Influence of Electrolyte Compositions and Electrical Parameters on Thermal Properties of Micro-Arc Oxidized AZ91 Alloy

Effect of Molybdate on Corrosion Performance of Oxide Coating Produced on 7075 Al Alloy Using PEO

Enhancement of mechanical properties and corrosion resistance of Mg–2Zn–0.5Zr–1.5Dy (mass%) alloy by a combination of heat treatment and hot extrusion

Contact Info

Product

Resources

About