Effects of Sodium Fluoride on Structure and Corrosion Resistance of Plasma Electrolytic Oxidation Ceramic Coatings on Magnesium Alloys

CORROSION ◽  
2010 ◽  
Vol 66 (8) ◽  
pp. 085002-085002-6 ◽  
Author(s):  
Z. P. Yao ◽  
X. R. Liu ◽  
L. L. Li ◽  
S. F. Qi ◽  
Z. H. Jiang
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
Sodium Fluoride ◽  
Plasma Electrolytic Oxidation ◽  
Ceramic Coatings ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Simultaneous Reduction of Wear and Corrosion of Titanium, Magnesium and Zirconium Alloys by Surface Plasma Electrolytic Oxidation Treatment

2008 ◽  
Vol 38 ◽  
pp. 27-35 ◽  
Author(s):  
H.M. Nykyforchyn ◽  
V.S. Agarwala ◽  
M.D. Klapkiv ◽  
V.M. Posuvailo
Keyword(s):  
Corrosion Resistance ◽  
Plasma Electrolytic Oxidation ◽  
Synthesis Method ◽  
Zirconium Alloys ◽  
Ceramic Coatings ◽  
Oxide Ceramic ◽  
Wear And Corrosion ◽  
Electrolytic Oxidation ◽  
Wear And Corrosion Resistance ◽  
Plasma Electrolytic

Titanium, magnesium and zirconium alloys are widely used in industrial applications, which require high wear and corrosion resistance. However current methods of improving these properties often do not satisfy the requirements of service and functional properties. An alternative approach is the application of oxide-ceramic coatings using high temperature process. The coatings are applied by spark discharge plasma in the metal-electrolyte system at high voltages - PEO (plasma electrolytic oxidation) as an oxide synthesis method. This method has shown good results for aluminium alloys and with good prospects to be used for titanium, magnesium and zirconium alloys. Development of PEO technology to improve the wear and corrosion resistance of titanium, magnesium and zirconium alloys is discussed in this paper. It describes the methods for obtaining the required layer-thickness for a specified hardness, porosity, wear and corrosion resistance, sets up the optimal process parameters (voltage/current) by taking the relation of anodic to cathodic currents into account, and establishing the electrolyte content of different dopants.

Corrosion Protection of a SiCp/ZL101 Composites by Using Plasma Electrolytic Oxidation Method

2009 ◽  
Vol 79-82 ◽  
pp. 1071-1074
Author(s):  
Shi Hai Cui ◽  
Hong Tao Tang ◽  
Jian Yu Li ◽  
Jian Min Han
Keyword(s):  
Corrosion Resistance ◽  
Plasma Electrolytic Oxidation ◽  
Salt Spray ◽  
Xrd Analysis ◽  
Ceramic Coatings ◽  
Immersion Test ◽  
Aluminum Composites ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Α Al2o3

A dense ceramic coatings with a thickness of 95μm was fabricated on a SiCp/ZL101 aluminum composites by using a plasma electrolytic oxidation(PEO) method. The XRD analysis showed that the PEO coating was mainly composed of α-Al2O3 γ-Al2O3 and mullite.The corrosion resistance of the PEO coatings and SiCp/ZL101 aluminum composites was estimated by the immersion test, salt spray test and electrochemical test. All the test results showed that the corrosion resistance of the composite was improved by the existence of the ceramic coating.

Corrosion Properties of Plasma Electrolytic Oxidation Ceramic Coatings on an A356 Alloy Tested in an Ethanol-Gasoline Fuel (E85) Medium

2011 ◽  
Vol 282-283 ◽  
pp. 774-778
Author(s):  
Zhi Jing Peng ◽  
Ying Chen ◽  
Xue Yuan Nie
Keyword(s):  
Corrosion Resistance ◽  
Plasma Electrolytic Oxidation ◽  
A356 Alloy ◽  
Current Mode ◽  
Ceramic Coatings ◽  
Corrosion Properties ◽  
Cross Sectional ◽  
Electrolytic Oxidation ◽  
Zero Resistance ◽  
Plasma Electrolytic

Ceramic oxide coatings were prepared on an aluminum A356 alloy by a plasma electrolytic oxidation (PEO) technique under unipolar, bipolar and duplex unipolar/bipolar current modes. Cross-sectional morphologies of the coatings were studied using a scanning electron microscope (SEM). The corrosion behavior of the coated and uncoated samples was evaluated in ethanol-gasoline E85 fuels through potentiodynamic polarization and zero resistance ammeter (ZRA) testing methods. The results indicated that all the coatings had a better corrosion resistance compared to the uncoated substrate. The unipolar current mode created the PEO coating with a thicker coating microstructure and thus a better corrosion resistance, compared to a bipolar current mode. The duplex treatments of unipolar/bipolar or bipolar/unipolar current modes produced the best performance of the coatings against galvanic corrosions caused by a steel/Al coupling in the E85 fuel medium.

TEM Analysis and Corrosion Resistance of the Ceramic Coatings on Q235 Steel Prepared by Hybrid Method of Hot-Dipping Aluminum and Plasma Electrolytic Oxidation

2012 ◽  
Vol 152-154 ◽  
pp. 40-45
Author(s):  
Li Hong Lu ◽  
De Jiu Shen ◽  
Jing Wu Zhang ◽  
Chang Hong Guo
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Hybrid Method ◽  
Plasma Electrolytic Oxidation ◽  
Sea Water ◽  
Composite Coatings ◽  
Ceramic Coatings ◽  
Q235 Steel ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

The hybrid method of plasma electrolytic oxidation (PEO) and hot-dipping aluminum (HDA) was employed to deposit composite ceramic coatings on the surface of Q235 steel. The cross-section microstructure and surface morphology of the treated specimens were investigated with scanning electron microscopy (SEM). Especially, the composition of the composite coatings was investigated with transmission electron microscopy (TEM). The corrosion resistance was analyzed by immersing and corrosion polarizing experiments. The results indicate that metallurgical bonding can be observed between the ceramic coatings and the steel substrate. There are many micro-pores which act as discharge channels in the PEO coatings. The phase composition of the ceramic coatings is mainly composed of amorphous phase and crystal Al2O3 oxides. The crystal Al2O3 phase includes κ- Al2O3, θ- Al2O3 and β- Al2O3.The corrosion resistance of the PEO samples is much better than that of the HDA samples whether immersed in the NaCl solution or in the sea water.

Structure and corrosion resistance of ZrO2 ceramic coatings on AZ91D Mg alloys by plasma electrolytic oxidation

2011 ◽  
Vol 509 (33) ◽  
pp. 8469-8474 ◽  
Author(s):  
Zhongping Yao ◽  
Yongjun Xu ◽  
Yunfu Liu ◽  
Dali Wang ◽  
Zhaohua Jiang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Plasma Electrolytic Oxidation ◽  
Ceramic Coatings ◽  
Mg Alloys ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Titanium carbide’s effects on coatings formed on D16T aluminum alloy by plasma electrolytic oxidation

2020 ◽  
Vol 67 (1) ◽  
pp. 48-58
Author(s):  
Wanying Liu ◽  
Junjie Yang ◽  
Yuhong Qiu ◽  
Ying Liu ◽  
Kuanhai Deng
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Titanium Carbide ◽  
Plasma Electrolytic Oxidation ◽  
Ceramic Coatings ◽  
Content Type ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Peo Coatings

Purpose The preferable concentration of titanium carbide was optimized and added as an additive to the micro-arc oxidation electrolyte to produce a high corrosion-resistant coating on D16T aluminum alloy. Design/methodology/approach Ceramic coatings were deposited on D16T aluminum alloy by plasma electrolytic oxidation in alkaline silicate electrolytes with micron titanium carbide particle suspending at different concentrations. Influences of additive concentration on morphology, elemental and phase composition and corrosion resistance of doped PEO coatings were evaluated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and electrochemical methods, respectively. Findings Results revealed that suspending titanium carbide additives incorporated into ceramic coatings through discharging channels and chemically transformed into amorphous stage. The content of titanium in the doped coatings increased with the increasing concentration of suspending micron additive. Compared with the coating without particle addition, the corrosion resistance of the coating produced in 8 g/L titanium carbide suspension increased more than 20 times. The result indicated that the incorporation of titanium into the PEO coatings formed on the D16T aluminum alloy could effectively improve the corrosion resistance. Originality/value The mechanism of corporation of TiC and the mechanism of improving the corrosion resistance of the coating were proposed.

Effects of Na2WO4 Additive on Properties of Plasma Electrolytic Oxidation Coatings on 6061 Al Alloy

2012 ◽  
Vol 550-553 ◽  
pp. 1969-1975 ◽  
Author(s):  
Xi Di Chen ◽  
Qi Zhou Cai ◽  
Li Song Yin
Keyword(s):  
Corrosion Resistance ◽  
Plasma Electrolytic Oxidation ◽  
Ceramic Coatings ◽  
Pulse Frequency ◽  
Inhibitory Effect ◽  
Al Alloy ◽  
Discharge Process ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Peo Coatings

Plasma electrolytic oxidation (PEO) ceramic coatings were prepared on 6061 aluminum alloy substrate in silicate based electrolyte with and without Na2WO4additive with different pulse frequency. The composition, surface morphology and corrosion resistance of PEO coatings were investigated by means of SEM, XRD, potentiodynamic polarization and EIS measurement in a 3.5% NaCl solution. These results show that Na2WO4can contributing to the transition from the metastable γ-Al2O3to a better thermal stability α-Al2O3, while has certain inhibitory effect on the deposition of SiO32-anion on the surface during the plasma discharge process. After adding Na2WO4in the electrolyte, the surface layer of PEO coatings are more smoother and less distinctly discharge holes appear which leads to the PEO coatings have better corrosion resistance than those of samples coated in the electrolyte without Na2WO4additive.

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