Residual stresses in plasma electrolytic oxidation coatings on Al alloy produced by pulsed unipolar current

Khan, Raja H.U.; Yerokhin, Aleksey; Pilkington, T.C.; Leyland, A.; Matthews, A.

doi:10.1016/j.surfcoat.2005.08.092

Cited by 116 publications

(50 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, it was noted that the coating thickness had increased with the increasing frequencies. This result conflicts with the result from the earlier work by other researcher, in which at low duty cycle of 20% the increasing frequency tends to decrease coating thickness, while at high duty cycle the effect of frequency becomes negligible [1]. This could be attributed to the difference in experimental conditions such as the substrate and the electrolyte compositions [9].…”

Section: Resultscontrasting

confidence: 86%

See 1 more Smart Citation

Influence of Applied Frequency on Microstructural and Electrochemical Characteristics of Ceramic Coating Produced on Al-Mg Alloy by Pulsed Plasma Electrolytic Oxidation

Lee

Kim

2016

Acta Phys. Pol. A

View full text Add to dashboard Cite

Plasma electrolytic oxidation (PEO) coating is gaining attention as a promising surface treatment technique for lightweight metals and alloys such as Al, Mg and Ti. The coating involves complex interactions among various process parameters including substrate composition, current modes and electrolyte composition. In this study, ceramic coating was produced in silicate based alkaline solution on Al-Mg alloy by pulsed PEO with different applied frequencies (100, 500, 1000, 2000 Hz). The resultant coating was characterized using FE-SEM, EDS and HR-XRD. The electrochemical characteristics of the PEO coating were also investigated in seawater solution. It was found that changing frequency in the PEO process had a prominent effect on both surface and crosssectional morphology of the coating. The electrochemical studies indicated that the pulsed PEO have improved the corrosion resistance of the Al-Mg substrate. In particular, the applied frequency of 100 Hz has produced one order of magnitude lower corrosion current density than that of the Al-Mg substrate.

show abstract

Section: Resultscontrasting

confidence: 86%

“…Yerokhin et al and R.O. Hussein et al related to the influence of electrical parameters on coating characteristics in pulsed PEO coating process for Al and Al alloys [1][2][3]. However, the materials in their investigations were limited to 1000 or 6000 series Al alloy, and only a few studies have dealt with Al-Mg alloy.…”

Section: Introductionmentioning

confidence: 99%

Influence of Applied Frequency on Microstructural and Electrochemical Characteristics of Ceramic Coating Produced on Al-Mg Alloy by Pulsed Plasma Electrolytic Oxidation

Lee

Kim

2016

Acta Phys. Pol. A

View full text Add to dashboard Cite

show abstract

“…As a result of the PEO coating process, the magnesium alloy surface is converted into ceramic-like coating layers that are hard, well adhered to the substrate and wear resistant [12,13]. PEO coatings mechanical and tribological properties depend on the characteristics schematically shown in Fig.…”

Section: Mechanical/tribological Propertiesmentioning

confidence: 99%

Plasma electrolytic oxidation (PEO) coatings on Mg-alloys for improved wear and corrosion resistance

Hussein¹,

Nie²,

Northwood³

2015

Surface and Contact Mechanics Including Tribology XII

View full text Add to dashboard Cite

Due to their high chemical reactivity, relatively low melting point and low hardness, magnesium and magnesium alloys have relatively poor corrosion and wear resistance. Since both corrosion and wear are surface phenomena, a number of surface engineering techniques have been used to improve corrosion and wear performance. Whilst some surface hardening/strengthening methods have led to improvements in wear properties, they have not, in themselves, significantly improved the corrosion performance. Plasma electrolytic oxidation (PEO) has the potential to produce hard, compact oxide coatings that are well adhered to the magnesium alloy substrate. Such coatings can provide both improved wear and corrosion resistance. In this paper we describe how by changing the PEO processing parameters (substrate alloy; electrolyte; current or voltage; processing time) we can change the nature of the PEO oxide coatings (thickness; microstructure; porosity; phase content; composition) which, in turn, effects the corrosion and wear performance. All PEO-coatings have a three-layer structure with a porous outer layer, and intermediate dense layer and a thin inner dense layer. From a corrosion aspect, the performance of coatings is determined by the time taken for corrosion to initiate since this is much shorter than time taken for the coating to degrade. For PEO-coated Mg-alloys, this initiation time is primarily determined by the thickness, porosity and phase content of the inner dense layer at the coating/substrate interface. With respect to tribological properties, the coefficient of friction (COF) in dry sliding wear increases with increasing surface roughness of the PEO coatings. The wear rate is primarily determined by the thickness and hardness of the intermediate dense layer.

show abstract

“…As a result of the PEO coating process, the magnesium alloy surface is converted into ceramic-like coating layers that are hard, well adhered to the substrate and wear resistant [15,16]. The mechanical and tribological properties of PEO coatings depend on the characteristics schematically shown in Fig.…”

Section: Mechanical/tribological Propertiesmentioning

confidence: 99%

Plasma electrolytic oxidation coatings on Mg-alloys for improved wear and corrosion resistance

Hussein¹,

Nie²,

Northwood³

2017

WIT Transactions on State-of-the-Art in Science and Engineering

View full text Add to dashboard Cite

Due to their high chemical reactivity, relatively low melting point and low hardness, magnesium and magnesium alloys have relatively poor corrosion and wear resistance. Since both corrosion and wear are surface phenomena, a number of surface engineering techniques have been used to improve corrosion and wear performance. Whilst some surface hardening/strengthening methods have led to improvements in wear properties, they have not, in themselves, significantly improved the corrosion performance. Plasma electrolytic oxidation (PEO) has the potential to produce hard, compact oxide coatings that are well adhered to the magnesium alloy substrate. Such coatings can provide both improved wear and corrosion resistance. In this contribution, it is shown how the nature of the PEO oxide coatings (thickness, microstructure, porosity, phase content, composition) can be changed by changing the PEO processing parameters (substrate alloy, electrolyte, current or voltage, processing time); this, in turn, effects the corrosion and wear performance. All PEO-coatings have a three-layer structure with a porous outer layer, an intermediate dense layer and a thin inner dense layer. From a corrosion aspect, the performance of coatings is determined by the time taken for corrosion to initiate since this is much shorter than the time taken for the coating to degrade. For PEO-coated Mg-alloys, this initiation time is primarily determined by the thickness, porosity and phase content of the inner dense layer at the coating/substrate interface. With respect to tribological properties, the coefficient of friction (COF) in dry sliding wear increases with increasing surface roughness of the PEO coatings. The wear rate is primarily determined by the thickness and hardness of the intermediate dense layer. Coatings containing less

show abstract

Residual stresses in plasma electrolytic oxidation coatings on Al alloy produced by pulsed unipolar current

Cited by 116 publications

References 6 publications

Influence of Applied Frequency on Microstructural and Electrochemical Characteristics of Ceramic Coating Produced on Al-Mg Alloy by Pulsed Plasma Electrolytic Oxidation

Influence of Applied Frequency on Microstructural and Electrochemical Characteristics of Ceramic Coating Produced on Al-Mg Alloy by Pulsed Plasma Electrolytic Oxidation

Plasma electrolytic oxidation (PEO) coatings on Mg-alloys for improved wear and corrosion resistance

Plasma electrolytic oxidation coatings on Mg-alloys for improved wear and corrosion resistance

Contact Info

Product

Resources

About