Robust Micro Arc Oxidation Coatings on 6061 Aluminum Alloys via Surface Thickening and Microvoid Reducing Approach

2018 ◽  
Vol 279 ◽  
pp. 148-152 ◽  
Author(s):  
Qing Jun Zhu ◽  
Bin Bin Wang ◽  
Xia Zhao ◽  
Bin Bin Zhang
Keyword(s):  
Wear Resistance ◽  
Ceramic Coatings ◽  
Al Alloy ◽  
Friction Resistance ◽  
Micro Arc Oxidation ◽  
Electrolyte Surface ◽  
Thickness Meter ◽  
6061 Al Alloy ◽  
Surface Morphologies ◽  
Scanning Electron

The hardness and wear resistance of micro arc oxidation (MAO) ceramic coatings were influenced by phase compositions, surface thickness, porosity and microcracks. In this work, ceramic coatings with enhanced microhardness and friction resistance were fabricated on 6061 Al-alloy by increasing thickness and decreasing porosity through adding sodium hexametaphosphate ((NaPO3)6) as additive in silicate-based electrolyte. Surface morphologies and microhardness of the as-fabricated MAO coatings were evaluated using scanning electron microscope (SEM) and thickness meter. As a binary additive, the addition of (NaPO3)6 in electrolytes can obviously change the surface morphologies, thickness and microhardness of the resultant MAO coatings.

Structure and Property of Micro Arc Oxidation Ceramic Coatings on Al Alloy in K2ZrF6 Solution

2010 ◽  
Vol 105-106 ◽  
pp. 505-508 ◽  
Author(s):  
Zhen Dong Wu ◽  
Zhong Wen Yao ◽  
Fang Zhou Jia ◽  
Zhao Hua Jiang
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Aluminium Alloy ◽  
Friction And Wear ◽  
Ceramic Coatings ◽  
Al Alloy ◽  
Structure And Property ◽  
Micro Arc Oxidation ◽  
Disk Friction ◽  
Composition Structure

The coatings containing zirconia were produced on LY12 Aluminium alloy by micro-arc oxidation in K2ZrF6 and NaH2PO2 solution. The composition, structure, hardness, friction and wear resistance and corrosion resistance of the coating were studied by XRD, SEM, EDS, ball-on-disk friction tester and electrochemical analyzer, respectively. The results show that coating was composed of m-ZrO2 and t-ZrO2. There were a large amount of Zr and O and a little Al, P and K in the coating. The thickness of coating prepared for 3h was 168μm and the maximum value of the hardness was up to 16.75GPa. The friction and wear resistance and corrosion resistance were improved, compared with the LY12 aluminium alloy substrate.

scholarly journals Characterization of self-sealing MAO ceramic coatings with green or black color on an Al alloy

RSC Advances ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 1597-1605 ◽  
Author(s):  
Wei Yang ◽  
Dapeng Xu ◽  
Jian Chen ◽  
Jiangnan Liu ◽  
Bailing Jiang
Keyword(s):  
Ceramic Coatings ◽  
Al Alloy ◽  
Electrolyte System ◽  
System P ◽  
Micro Arc Oxidation ◽  
6061 Al Alloy ◽  
Black Color

Micro arc oxidation (MAO) coatings with green or black color were obtained on a 6061 Al alloy in a new Cr-containing electrolyte system.

Evolution of residual stresses in micro-arc oxidation ceramic coatings on 6061 Al alloy

2013 ◽  
Vol 26 (6) ◽  
pp. 1149-1153 ◽  
Author(s):  
Dejiu Shen ◽  
Jingrui Cai ◽  
Changhong Guo ◽  
Peiyu Liu
Keyword(s):  
Residual Stresses ◽  
Ceramic Coatings ◽  
Al Alloy ◽  
Micro Arc Oxidation ◽  
6061 Al Alloy

scholarly journals Morphology and Wear Resistance of Composite Coatings Formed on a TA2 Substrate Using Hot-Dip Aluminising and Micro-Arc Oxidation Technologies

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 799 ◽  
Author(s):  
Shaopeng Wang ◽  
Lian Zhou ◽  
Changjiu Li ◽  
Zhengxian Li ◽  
Hongzhan Li
Keyword(s):  
Wear Resistance ◽  
Surface Composition ◽  
Pure Titanium ◽  
Titanium Substrate ◽  
Ceramic Coatings ◽  
Oxide Ceramic ◽  
Pure Aluminium ◽  
X Ray ◽  
Micro Arc Oxidation

Aluminium layers were coated onto the surface of pure titanium using hot-dip aluminising technology, and then the aluminium layers were in situ oxidised to form oxide ceramic coatings, using the micro-arc oxidation (MAO) technique. The microstructure and composition distribution of the hot-dip aluminium coatings and ceramic layers were studied by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The phase structure of the MAO layers was studied using X-ray diffraction. The surface composition of the MAO layer was studied by X-ray photoelectron spectroscopy. The wear resistance of the pure titanium substrate and the ceramic layers coated on its surface were evaluated by using the ball-on-disc wear method. Therefore, aluminising coatings, which consist of a diffusion layer and a pure aluminium layer, could be formed on pure titanium substrates using the hot-dip aluminising method. The MAO method enabled the in-situ oxidation of hot-dip pure aluminium layers, which subsequently led to the formation of ceramic layers. Moreover, the wear resistance values of the ceramic layers were significantly higher than that of the pure titanium substrate.

The Effects of Magnetic Field on Micro-Arc Oxidation Ceramic Coating on Magnesium Alloys

2014 ◽  
Vol 960-961 ◽  
pp. 143-147
Author(s):  
Jun Zhao ◽  
Jian Jun Xi ◽  
Zhi Gang Wang ◽  
Chun Ping Zhao
Keyword(s):  
Magnetic Field ◽  
Corrosion Resistance ◽  
Electron Microscope ◽  
Friction Coefficient ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Oxidation Method ◽  
Polarization Test ◽  
Micro Arc Oxidation ◽  
Scanning Electron

Ceramic coatings were prepared on ZM5 magnetism substrate by micro-arc oxidation method with and without magnetism filed in silicate electrolyte. The morphology of the MAO coatings was investigated by scanning electron microscope (SEM). The friction coefficient of the MAO coatings prepared with magnetism is about 0.2 and more stable than the coatings prepared without magnetism. The polarization test indicated that the coating prepared with magnetism has better corrosion resistance.

Effects of graphene on the microstructure and properties of MAO coatings formed on AA7050

2020 ◽  
Vol 111 (6) ◽  
pp. 463-468
Author(s):  
Bo Xu ◽  
Yafeng He ◽  
Xiangzhi Wang ◽  
Weimin Gan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Composite Coatings ◽  
Ceramic Coatings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Scanning Electron

Abstract Ceramic coatings were prepared on the surface of 7050 highstrength aluminum alloy using micro-arc oxidation in an aluminate electrolyte with added graphene. To analyze the surface morphology, roughness, phase composition, and corrosion resistance, scanning electron microscopy, X-ray diffraction, X-ray photoelectron, and electrochemical measurements were used, respectively. The addition of 9 g · L-1 of graphene to the electrolyte decreased the micro-pore size of the composite coatings and improved the density. In addition, with the addition of graphene, the roughness was the lowest, and the corrosion resistance was significantly improved.

Influences of Calcination Ambiences on Morphologies, Phase Composition and Contents of the Elements of Ceramic Coatings on Ti Alloy by Micro-Arc Oxidation

2012 ◽  
Vol 512-515 ◽  
pp. 1066-1069
Author(s):  
Jin Xue Zhang
Keyword(s):  
Electron Microscopy ◽  
Phase Composition ◽  
Ceramic Coatings ◽  
Ti Alloy ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Oxidation Properties ◽  
Α Al2o3 ◽  
Scanning Electron

Compound ceramic coatings with the main crystal phase of Al2TiO5 (as-coated samples) were prepared in situ on the surface of Ti-6Al-4V alloy by means of pulsed bi-polar micro-arc oxidation (MAO) in an NaAlO2 solution. The coated samples were calcined in argon and air at 1000 oC, respectively. The phase composition, surface and section morphology, and element contents of the ceramic coatings were investigated by X-ray diffractometry (XRD), Scanning electron microscopy (SEM) and X-ray fluorescence spectroscopy (XRF). The samples were treated in argon and the as-coated ones were calcined in air at 1000 oC to study the anti-oxidation properties of the samples. The results show that Al2TiO5 had been decomposed in an hour and transformed into α-Al2O3 and rutile TiO2 in air. However, Al2TiO5 had been decomposed in four hours in argon and the final coating surface was completely composed of α-Al2O3. The content of Al2O3 was decreased from outside to inside layers and Ti2O3 was formed in the coating. Furthermore, the morphology of the ceramic coatings after the calcination was different. The coatings calcined in argon were finer; the grains and pores were smaller than those in air.

Effects of Rare Earth (RE) Additives on Performances of Micro-Arc Oxidation Coatings Formed on Aluminum Alloy

2013 ◽  
Vol 850-851 ◽  
pp. 140-143 ◽  
Author(s):  
Dan Huang ◽  
Xiao Yan Zhang ◽  
De Feng Wu ◽  
Xiao Song Zhou
Keyword(s):  
Wear Resistance ◽  
Aluminum Alloy ◽  
Friction And Wear ◽  
Alloy Sample ◽  
X Ray Diffraction ◽  
X Ray ◽  
Micro Cracks ◽  
Micro Arc Oxidation ◽  
Α Al2o3 ◽  
Scanning Electron

Scanning electron microscope (SEM), X-ray diffraction (XRD), VSP electrochemical workstation and friction and wear tester equipment are applied for comparing the effects on organizations and properties of micro-arc oxidation fabricated on a piece of aluminum alloy sample with additives of La (NO3)3 or Ce (SO4)2. The results revealed that both coatings with these two different additives are consisted of α-Al2O3 and γ-Al2O3, but the peaks of main phases are evident with La (NO3)3. Compared the two different coatings, it could be found that less micro-cracks can be observed from the coating with La (NO3)3 additive. Beside this, aperture in this coating is also smaller and corrosion resistance and wear resistance are much better.

Corrosion and Wear Properties of h-BN Modified TC4 Titanium Alloy Micro-Arc Oxide Coatings

2022 ◽  
pp. 1-10
Author(s):  
X W Chen ◽  
P Ren ◽  
D F Zhang ◽  
J Hu ◽  
C Wu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Titanium Alloy ◽  
Hexagonal Boron Nitride ◽  
Corrosion Current ◽  
Ceramic Coatings ◽  
Element Distribution ◽  
Wear Properties ◽  
Tc4 Titanium Alloy ◽  
Micro Arc Oxidation

In this study, ceramic coatings were prepared on the surface of TC4 titanium alloy by micro-arc oxidation (MAO). The morphology, element distribution and phase composition of MAO coatings were analyzed by SEM, EDS, XRD and other analytical methods. The effect of hexagonal boron nitride(h-BN) doping on wear resistance and corrosion resistance of micro-arc oxidation layer was studied. The results show that the coating is mainly composed of rutile TiO2, anatase TiO2 and a small amount of h-BN. Furthermore, the composite coating containing h-BN was less porous than particle-free coating. The test results show that h-BN doping slightly affects the hardness of the MAO coating, and it is helpful in improving the thickness, corrosion resistance and wear resistance of the coatings. When the amount of h-BN is 3 g/L, the corrosion current density of the coating is the smallest; When the addition of h-BN is 1.5 g/L, the friction coefficient of the coating is the smallest. The wear mechanism was adhesive wear, accompanied by slight abrasive wear.

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