scholarly journals A Review on LDH-Smart Functionalization of Anodic Films of Mg Alloys

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 536
Author(s):  
Mosab Kaseem ◽  
Karna Ramachandraiah ◽  
Shakhawat Hossain ◽  
Burak Dikici
Keyword(s):  
Industrial Applications ◽  
Mg Alloys ◽  
Anodic Films ◽  
Electrolytic Oxidation ◽  
Recent Developments ◽  
Plasma Electrolytic ◽  
Co Precipitation ◽  
Corrosive Environments ◽  
Double Hydroxide

This review presents an overview of the recent developments in the synthesis of layered double hydroxide (LDH) on the anodized films of Mg alloys prepared by either conventional anodizing or plasma electrolytic oxidation (PEO) and the applications of the formed composite ceramics as smart chloride traps in corrosive environments. In this work, the main fabrication approaches including co-precipitation, in situ hydrothermal, and an anion exchange reaction are outlined. The unique structure of LDH nanocontainers enables them to intercalate several corrosion inhibitors and release them when required under the action of corrosion-relevant triggers. The influences of different variables, such as type of cations, the concentration of salts, pH, and temperature, immersion time during the formation of LDH/anodic film composites, on the electrochemical response are also highlighted. The correlation between the dissolution rate of PEO coating and the growth rate of the LDH film was discussed. The challenges and future development strategies of LDH/anodic films are also highlighted in terms of industrial applications of these materials.

scholarly journals Plasma Electrolytic Oxidation (PEO) Process—Processing, Properties, and Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1375
Author(s):  
Soumya Sikdar ◽  
Pramod V. Menezes ◽  
Raven Maccione ◽  
Timo Jacob ◽  
Pradeep L. Menezes
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Nanocomposite Coatings ◽  
Mechanical And Tribological Properties ◽  
Electrolytic Oxidation ◽  
Recent Developments ◽  
Coating Formation ◽  
Wear And Corrosion Resistance ◽  
Plasma Electrolytic ◽  
Peo Coatings ◽  
Future Work

Plasma electrolytic oxidation (PEO) is a novel surface treatment process to produce thick, dense metal oxide coatings, especially on light metals, primarily to improve their wear and corrosion resistance. The coating manufactured from the PEO process is relatively superior to normal anodic oxidation. It is widely employed in the fields of mechanical, petrochemical, and biomedical industries, to name a few. Several investigations have been carried out to study the coating performance developed through the PEO process in the past. This review attempts to summarize and explain some of the fundamental aspects of the PEO process, mechanism of coating formation, the processing conditions that impact the process, the main characteristics of the process, the microstructures evolved in the coating, the mechanical and tribological properties of the coating, and the influence of environmental conditions on the coating process. Recently, the PEO process has also been employed to produce nanocomposite coatings by incorporating nanoparticles in the electrolyte. This review also narrates some of the recent developments in the field of nanocomposite coatings with examples and their applications. Additionally, some of the applications of the PEO coatings have been demonstrated. Moreover, the significance of the PEO process, its current trends, and its scope of future work are highlighted.

scholarly journals Fatigue Behavior of an AM50 Die-Casting Alloy Anodized by Plasma Electrolytic Oxidation

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7795
Author(s):  
Kwangmin Choi ◽  
Seungwon Kang ◽  
Heon Kang
Keyword(s):  
Fatigue Behavior ◽  
Plasma Electrolyte ◽  
Die Cast ◽  
Electrolytic Oxidation ◽  
Alkaline Phosphate ◽  
Excellent Adhesion ◽  
Plasma Electrolytic ◽  
High Dielectric ◽  
Plasma Electrolyte Oxidation ◽  
Corrosive Environments

While an anodizing process is essential for magnesium alloys to be used under corrosive environments, it sometimes stimulates a fatigue fracture that initiates at the interface between the coating layer and the substrate. In this study, a plasma electrolyte oxidation (PEO) technique was employed to provide excellent adhesion between the anodizing layer and the AM50 die-cast by applying an extremely high dielectric discharge in an alkaline phosphate electrolyte, and its effect on corrosion and fatigue behaviors was investigated. The stress intensity factor at the fatigue limit was estimated to be 0.28 MPam0.5. The specimen anodized using the PEO technique exhibits enhanced strength and corrosion resistance compared to the unanodized counterpart. Furthermore, it shows a relative fatigue life in spite of the thick anodizing layer because the crack initiates from the interface, not from the pore near the interface.

Characterization of Polystyrene (PS)/Organomodified Layered Double Hydroxide (OLDH) Nanocomposites Prepared by In Situ Polymerization

2011 ◽  
Vol 410 ◽  
pp. 164-167 ◽  
Author(s):  
Balakrushna Sahu ◽  
G. Pugazhenthi
Keyword(s):  
In Situ Polymerization ◽  
Sodium Dodecyl ◽  
Decomposition Temperature ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Stretching Vibration ◽  
Xrd Patterns ◽  
Co Precipitation ◽  
Double Hydroxide

PS/LDH nanocomposites were synthesized via in-situ polymerization technique using styrene monomer with toluene as a solvent. A series of LDHs (Mg-Al, Co-Al, Ni-Al, Cu-Al, Cu-Fe and Cu-Cr LDHs) was first prepared from their nitrate salts by co-precipitation method. The above prepared, pristine LDHs were organically modified using sodium dodecyl sulfate (SDS) to obtain organomodified LDHs (OLDH). Then, PS nanocomposites containing 5 wt.% OLDHs were prepared by in-situ polymerization method. The structural and thermal properties of LDHs and corresponding nanocomposites were characterized by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA). The absence of OLDH peak (003) in the XRD patterns of PS/OLDH nanocomposite confirms the formation of exfoliated nanocomposites. The presence of sulfate groups in the modified LDHs is confirmed by FTIR analysis. The appearance of new peaks in the FTIR spectra in the region of 3400-3500 cm-1, 1670-1680 cm-1and 1200-1260 cm-1for O-H stretching, H-O-H vibration and stretching vibration of sulfate, respectively indicate the existence of LDHs in the PS/OLDH nanocomposites. The entire exfoliated PS/OLDH nanocomposites exhibit enhanced thermal stability relative to the pure PS. When 50% weight loss is selected as point of comparison, the decomposition temperature of nanocomposites is about 3-5oC higher than that of pure PS.

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