Dual incorporation of SiO 2 and ZrO 2 nanoparticles into the oxide layer on 6061 Al alloy via plasma electrolytic oxidation: Coating structure and corrosion properties

2017 ◽  
Vol 707 ◽  
pp. 358-364 ◽  
Author(s):  
S. Fatimah ◽  
M.P. Kamil ◽  
J.H. Kwon ◽  
M. Kaseem ◽  
Y.G. Ko
Keyword(s):  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Al Alloy ◽  
Coating Structure ◽  
Corrosion Properties ◽  
Plasma Electrolytic Oxidation Coating ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
6061 Al Alloy

scholarly journals PLASMA ELECTROLYTIC OXIDATION COATING ON 6061 AL ALLOY USING AN ELECTROLYTE WITHOUT ALKALI IONS

2018 ◽  
Vol 54 (5A) ◽  
pp. 151 ◽  
Author(s):  
Quang Phu Tran
Keyword(s):  
Corrosion Resistance ◽  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Free Alkali ◽  
Al Alloy ◽  
Micro Hardness ◽  
Alkali Ions ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
6061 Al Alloy

Plasma electrolytic oxidation (PEO) technique is well known to use for modifying the surface of valve metal such as Al, Mg and Ti, which improves mechanical and corrosion resistance properties. PEO is an electrochemical process of oxidation by creating micro-discharges on the surface of metal immersed in an electrolyte under applying a high voltage. Electrolyte used in PEO process is almost based on alkali ions such as Na ion. The report on PEO process using free-alkali ion is very rare. In this study, the oxide layer on 6061 Al alloy was produced in a free-alkali ion electrolyte containing calcium phosphate and ammonia water by PEO method. Microstructure, micro-hardness and corrosion resistance of PEO coated were investigated and discussed. Surface morphology analysis indicated the coating characterized by micro-pores, pan-cakes like, and micro-crakes with pore size and percentage of pores on coating surface are smaller than 1 mm and 2.5 %, respectively. Micro-hardness and corrosion resistance of PEO coated are greatly improved compared to the bare Al alloy. Free-alkali-ions in oxide layer coated on Al alloy is important for many applications today.

Oxide Layer Modification of Mg-Al Alloy Coated by Plasma Electrolytic Oxidation Using Zirconia Particles

2012 ◽  
Vol 463-464 ◽  
pp. 406-409 ◽  
Author(s):  
D.Y. Choi ◽  
J. Hwang ◽  
K.M. Lee ◽  
K.R. Shin ◽  
Y.G. Ko ◽  
...  
Keyword(s):  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Al Alloy ◽  
Zirconia Powder ◽  
Corrosion Properties ◽  
Electrolytic Oxidation ◽  
Valve Metal ◽  
Structure Observation ◽  
Plasma Electrolytic ◽  
Peo Coatings

The paper reported the effect of zirconia incorporation on the oxide layer modification of the valve metal such as magnesium coated by plasma electrolytic oxidation (PEO). To incorporate zirconia particles into the oxide layer, PEO coatings were carried out under AC condition in electrolytes containing zirconia powder. After PEO coatings, structure observation revealed that a number of zirconia particles were distributed uniformly throughout the oxide layer while the size and distribution of pores remained unchanged as compared to the results coated by PEO without zirconia. It was found that fine zirconia particles incorporated into the oxide layers played an important role in enhancing the anti-corrosion properties of bare metal.

ffect of Na2WO4 in electrolyte on mechanical properties of oxide layer on Al alloy via plasma electrolytic oxidation

2015 ◽  
Vol 53 (8) ◽  
pp. 535-540 ◽  
Author(s):  
Young Gun Ko ◽  
Dong Hyuk Shin ◽  
Hae Woong Yang ◽  
Yeon Sung Kim ◽  
Joo Hyun Park ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Al Alloy ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

scholarly journals Bioactivity Performance of Pure Mg after Plasma Electrolytic Oxidation in Silicate-Based Solutions

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2094
Author(s):  
Yevheniia Husak ◽  
Joanna Michalska ◽  
Oleksandr Oleshko ◽  
Viktoriia Korniienko ◽  
Karlis Grundsteins ◽  
...  
Keyword(s):  
Cell Culture ◽  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Oxide Coating ◽  
Mg Alloy ◽  
Aureus Strain ◽  
Active Surface Area ◽  
Corrosion Properties ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

The biodegradable metals, including magnesium (Mg), are a convenient alternative to permanent metals but fast uncontrolled corrosion limited wide clinical application. Formation of a barrier coating on Mg alloys could be a successful strategy for the production of a stable external layer that prevents fast corrosion. Our research was aimed to develop an Mg stable oxide coating using plasma electrolytic oxidation (PEO) in silicate-based solutions. 99.9% pure Mg alloy was anodized in electrolytes contained mixtures of sodium silicate and sodium fluoride, calcium hydroxide and sodium hydroxide. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), contact angle (CA), Photoluminescence analysis and immersion tests were performed to assess structural and long-term corrosion properties of the new coating. Biocompatibility and antibacterial potential of the new coating were evaluated using U2OS cell culture and the gram-positive Staphylococcus aureus (S. aureus, strain B 918). PEO provided the formation of a porous oxide layer with relatively high roughness. It was shown that Ca(OH)2 was a crucial compound for oxidation and surface modification of Mg implants, treated with the PEO method. The addition of Ca2+ ions resulted in more intense oxidation of the Mg surface and growth of the oxide layer with a higher active surface area. Cell culture experiments demonstrated appropriate cell adhesion to all investigated coatings with a significantly better proliferation rate for the samples treated in Ca(OH)2-containing electrolyte. In contrast, NaOH-based electrolyte provided more relevant antibacterial effects but did not support cell proliferation. In conclusion, it should be noted that PEO of Mg alloy in silicate baths containing Ca(OH)2 provided the formation of stable biocompatible oxide coatings that could be used in the development of commercial degradable implants.

scholarly journals CHARACTERISTICS OF PLASMA ELECTROLYTIC OXIDATION COATINGS ON 6061 AL ALLOY PREPARED AT DIFFERENT CURRENT DENSITIES

2020 ◽  
Vol 58 (6) ◽  
pp. 699
Author(s):  
Quang-Phu Tran ◽  
Van-Da Dao ◽  
Van-Hoi Pham
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Current Mode ◽  
Coated Sample ◽  
Al Alloy ◽  
Properties Of Coatings ◽  
Sem Images ◽  
Oxide Layers ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
6061 Al Alloy

Plasma electrolytic oxidation (PEO) has earned much attention due to its powerful and easy formation of hard and corrosion-resistant oxide layers on valve metals, such as Al alloys. Here we report the effects of current density (CD) on microstructure and properties of coatings on 6061 Al alloy by PEO using direct current mode. The electrolyte contains the chemicals of Na2SiO3, Na2WO4´2H2O, and NaH2PO2´H2O. The CDs adopted 5.0, 7.5, 10.0, and 12.5 A/dm2, respectively, for a fixed PEO time of 30 min. The thickness, surface morphology, phase composition, hardness, and corrosion resistance of PEO coatings as the function of the applied CD have been studied and discussed. Studied results show the coating thickness is proportional to the applied CD. When the applied CD increases 2.5 times from 5.0 to 12.5 A/dm2, the growth rate of oxide layers increased by more than 3.5 times, from 0.423 to 1.493 μm/min, respectively. SEM images are characterized by a reduction in the ratio of agglomerate-bumps-region/flatten-region as applied CD increases. However, cracks and larger pores appear when the applied CD is higher than 10.0 A/dm2. X-ray diffraction pattern shows that the main phases of Al, g-Al2O3, α-Al2O3, and W are contained in all coatings. PEO coated sample has the highest hardness of 1290 HV and highest polarization resistance of 8.80 ´ 106 Wcm2 obtained at applied CD 10 A/dm2 which shows the best performance of the coating. The variation in coating performance is explained by microstructure details, specifically phases, compositions of oxide-layers, and micro-pores and cracks.

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