Preparation and Tribological Properties of Graphite-Containing Plasma Electrolytic Oxidation Coatings on Al Alloy

2014 ◽  
Vol 1081 ◽  
pp. 183-186
Author(s):  
Qing Biao Li ◽  
Qing Wang ◽  
Jun Liang

Graphite-containing plasma electrolytic oxidation (PEO) composite coatings were prepared on Al alloy using periodically constant voltage, with addition of graphite in silicate electrolyte. The surface and cross-sectional morphologies of the coatings were examined using scanning electron microscope (SEM), the composition of the coatings was investigated by X-ray diffraction (XRD) and Raman spectra, the tribological properties of the coatings were evaluated on a tribometer. The results show that friction-reducing PEO composite coatings on Al alloy can be prepared in graphite-dispersed electrolyte using periodically constant voltage, the yielded coatings exhibit relatively lower and more stable friction coefficient.

2021 ◽  
Vol 19 ◽  
pp. 228080001882225
Author(s):  
Marko Magić ◽  
Božana Čolović ◽  
Saša Vasilijić ◽  
Nenad Tadić ◽  
Stevan Stojadinović ◽  
...  

The titanium implant was treated with plasma electrolytic oxidation and subsequent ionic exchange and thermal treatment in order to obtain bioactive layer consisting of titanium oxide, calcium and sodium titanates and hydroxyapatite, as confirmed by X-ray diffraction (XRD). Scanning electron microscopy (SEM) revealed that the given method, besides corresponding phase composition, enables suitable nanotopology for cell attachment and proliferation. Cytotoxicity investigations by MTT, LDH and propidium iodide assays and light microscopy showed that these coatings were not toxic to L929 cells.


2021 ◽  
Vol 8 (6) ◽  
pp. 974-989
Author(s):  
Jie Sun ◽  
◽  
Tzvetanka Boiadjieva-Scherzer ◽  
Hermann Kronberger ◽  

<abstract> <p>To imitate the superior biocompatibility of Ti–Zr alloys at reduced cost, conventional Ti6Al4V alloy was modified via plasma electrolytic oxidation (PEO). The influence of different additives on the phase composition and topography was investigated in acidic electrolytes containing Zr(SO<sub>4</sub>)<sub>2</sub>·H<sub>2</sub>O with potentiostatically controlled PEO at different pulse frequencies. Apart from the primary intention to generate Zr enriched phases, formation and incorporation in the ceramic layer of potential antibacterial Cu and Zn species was achieved and examined by X-ray diffraction. The thickness of the oxide layer, the adhesion and the layers' composition were evaluated using FIB and SEM-EDX.</p> </abstract>


2018 ◽  
Vol 25 (05) ◽  
pp. 1850102 ◽  
Author(s):  
Y. ZHANG ◽  
W. FAN ◽  
H. Q. DU ◽  
Y. W. ZHAO

Plasma electrolytic oxidation (PEO) coatings were formed on aluminium alloy in additive Al2O3- and TiO2-containing Na2SiO3-based electrolytes, respectively. The effect of these additives on morphology, composition and wearing properties of coatings was investigated. The morphology and composition of coatings were studied by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS). Analysis of wearing properties of coatings were done by friction and wearing experiment. It was found that the use of additives greatly affects the surface morphology of coatings. It is shown that the content of [Formula: see text]-Al2O3 in coatings formed in Al2O3-containing electrolytes increased with the addition of Al2O3. However, the content of [Formula: see text]-Al2O3 in coatings formed in TiO2-containing electrolytes first increased and then decreased. Among these coatings, the coating formed in silicate-based electrolytes system containing 7[Formula: see text]g/L Al2O3 showed the most superior wearing properties.


Author(s):  
Maria-Magdalena DICU ◽  
◽  
Paul-Costinel DICU

This paper presents elaboration and structural characterization of surface layers formed on aluminumalloys by plasma electrolytic oxidation (PEO). The electrolyte is a mixture consisting: sodium metasilicate and sodium hydroxide. The coatings obtained by PEO were investigated with: scanning electron microscopy (SEM) with Energy dispersive X-ray spectrometer (EDX) and X-ray diffraction (XRD)techniques.


2020 ◽  
Vol 27 (11) ◽  
pp. 2050007
Author(s):  
KOANGYONG HYUN ◽  
JUNG-HYUNG LEE ◽  
SEONG-JONG KIM

Plasma electrolytic oxidation (PEO) is an electrochemical-based surface modification technique that produces oxide layers on valve metals. The PEO process is performed in an electrolyte solution, which offers the possibility of particles’ incorporation into the growing oxide layer. In this study, we employed a PEO technique on a commercial Al alloy in an aqueous suspension of carbon nanotubes (CNTs) to fabricate CNT-incorporated oxide layer. The voltage–time response was recorded during the process. The surface of the resulting oxide layer was characterized by means of a scanning electron microscope (SEM), an energy-dispersive X-ray spectrometer (EDS), and X-ray diffraction (XRD). It was found from the SEM observation that the CNTs were successfully incorporated into the oxide layer. The PEO with the addition of CNTs led to a delay in time to breakdown (50[Formula: see text][Formula: see text][Formula: see text]s) and a decrease in breakdown voltage (442[Formula: see text][Formula: see text][Formula: see text]V) in the voltage–time curve. The microstructural feature was clearly distinguishable between the oxide layers produced with and without CNTs: a pancake-like structure for PEO without CNTs, and a doughnut-like structure for PEO with CNTs. However, neither the results of the structure analysis nor the elemental analysis provides a clear indication of carbon, even though the presence of CNTs in the oxide layer is evident, suggesting that further optimization of CNT concentration is required.


2019 ◽  
Vol 69 (12) ◽  
pp. 3490-3493
Author(s):  
Elisabeta Coaca ◽  
Alexandru Marin ◽  
Oana Rusu ◽  
Viorel Malinovschi ◽  
Victor Andrei

Anticorrosion layers were prepared on commercial Zr-2.5%Nb alloy by employing plasma electrolytic oxidation (PEO) process in aqueous electrolyte solutions. Microstructure and electrochemical behavior were evaluated using X-ray diffraction (XRD), optical metallography and potentiodynamic polarization measurements. The obtained coatings are uneven, presenting a dominant monoclinic crystallographic phase of ZrO2. Enhanced corrosion resistance was attributed to the PEO-treated samples compared to the commercial black oxide coating.


2010 ◽  
Vol 123-125 ◽  
pp. 1063-1066 ◽  
Author(s):  
Kai Wang ◽  
Sang Sik Beyun ◽  
Bon Heun Koo ◽  
Yi Qi Wang ◽  
Jung I. Song

The ceramic coatings were prepared on the T6-tempered Al6061 alloy substrate under a hybrid voltage by PEO treatment in 5-30 min in a phosphate electrolyte. The X-Ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the coating microstructures. With increasing the PEO treating time, the different compositions of coatings eliminate the sharp slope of the microhardness profile. The coatings PEO-treated in 30min presents excellent abrasive resistance property.


Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2739 ◽  
Author(s):  
Vladimir S. Egorkin ◽  
Ivan M. Medvedev ◽  
Sergey L. Sinebryukhov ◽  
Igor E. Vyaliy ◽  
Andrey S. Gnedenkov ◽  
...  

Wrought Al-Cu-Mg aluminum alloy (D16) was treated by bipolar plasma electrolytic oxidation to create a base plasma electrolytic oxidation (PEO)-coating with corrosion protection and mechanical properties superior to bare alloy’s natural oxide layer. Additional protection was provided by the application of polymer, thus creating a composite coating. Electrochemical and scratch tests, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction studies were performed. Degradation of coatings in the marine atmosphere and seawater was evaluated. The composite polymer-containing coating provided better corrosion protection of aluminum alloy compared to the PEO-coating, although seawater affected both. During the atmospheric exposure, the PEO-coating provided reasonably good protection, and the composite coating showed excellent performance.


Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 170 ◽  
Author(s):  
Limei Ren ◽  
Tengchao Wang ◽  
Zhaoxiang Chen ◽  
Yunyu Li ◽  
Lihe Qian

A self-lubricating plasma electrolytic oxidation–polytetrafluoroethylene (PEO–PTFE) composite coating was successfully fabricated on the surface of commercially pure titanium by a multiple-step method of plasma electrolytic oxidation, dipping and sintering treatment. The microstructure and tribological properties of the PEO–PTFE composite coating were investigated and compared with the PEO TiO2 coating and the PTFE coating on titanium. Results show that most of the micro-pores of the PEO TiO2 coating were filled by PTFE and the surface roughness of PEO–PTFE composite coating was lower than that of the PEO TiO2 coating. Furthermore, the PEO–PTFE composite coating shows excellent tribological properties with low friction coefficient and low wear rate. This study provides an insight for guiding the design of self-lubricating and wear-resistant PEO composite coatings.


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