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

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.

2018 ◽  
Vol 279 ◽  
pp. 148-152 ◽  
Author(s):  
Qing Jun Zhu ◽  
Bin Bin Wang ◽  
Xia Zhao ◽  
Bin Bin Zhang

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.


2007 ◽  
Vol 353-358 ◽  
pp. 1895-1898 ◽  
Author(s):  
Wan Hui Liu ◽  
Ai Lian Bao ◽  
Xin Yu Mao ◽  
Guang Hai Zheng

The paper discusses structure and property aspects of oxide films formed on 7075 aluminum alloys by microarc oxidation in alkali-silicate electrolytic solution. Microstructure, surface morphology and phase composition of the ceramic coatings were investigated by SEM and XRD. Distribution of hardness along the coating thickness was determined by microhardness analyses. The friction and wear behavior of the oxide films against steel counterparts was evaluated with a friction and wear tester. The results showed that the microarc oxidation coatings composed mainly of α-Al2O3 and γ-Al2O3 phase are dense and uniform, which indicates that the wear resistance of Al alloy could be improved obviously by microarc oxidation. The films possess a beneficial combination of 25~45 μm thickness, HV0.11500 microhardness and provide a low wear rate but a relatively high friction coefficient against GCr15 steel under dry friction condition.


2022 ◽  
pp. 1-10
Author(s):  
X W Chen ◽  
P Ren ◽  
D F Zhang ◽  
J Hu ◽  
C Wu ◽  
...  

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.


2012 ◽  
Vol 538-541 ◽  
pp. 368-372 ◽  
Author(s):  
Yu Gang Zheng ◽  
Hui Zhou ◽  
Han Jun Hu ◽  
Kai Feng Zhang ◽  
Zhi Hua Wang ◽  
...  

The ceramic coatings, on the substrate of LY12 Al alloy, were prepared by micro-arc oxidation (MAO) technique with different electrical source parameters. The microstructure and tribological properties of the resulting micro-arc oxidation ceramic coatings(MAOC) were tested and analyzed by Nano-scratch tester, Micro-hardness tester and ball-on-disk friction tester etc. The results indicate that the thickness, roughness, micropore sizes and wear-resistance of MAOC increase with impulse frequency decreasing, however, the porosity is correspondingly reduced.


2011 ◽  
Vol 189-193 ◽  
pp. 1248-1252 ◽  
Author(s):  
Rui Ling Jia ◽  
Hong Ping Duan ◽  
Feng Guo ◽  
Xi Wei Zhai ◽  
Ya Hong Liang

Aluminium plate was cladded to magnesium alloy plate by using the explosive welding. The bonding morphology and composition of the explosive cladding plate was inspected by SEM and EDS. There is a wave bonding at the interface between aluminum plate and magnesium alloy plate. Then ceramic coatings were directly prepared on the surface of aluminum and magnesium alloy by micro-arc oxidation (MAO) in the same solution and at the same time. The microstructure and composition of MAO coatings were studies by SEM and EDS. The corrosion and wear resistance of MAO coatings on the two sides of the clad plate were investigated by salt spray tests and friction-wear test. The results show that the MAO coating on the Al surface consists of Al, O and Si elements, while MAO coating on the Mg surface consists of Mg, O and Si elements. The corrosion resistance of MAO coating on the Al surface was better than that on Mg surface of the explosive clad plate. The MAO coatings both on the Al surface and on the Mg surface can obviously improve the wear resistance of substrate.


Author(s):  
Lida Shen ◽  
Yinhui Huang ◽  
Zongjun Tian ◽  
Guoran Hua

This paper describes an investigation of nano-Al2O3 powders reinforced ceramic coatings, which has included NiCrAl and Al2O3+13%wt.TiO2 coats pre-produced by atmosphere plasma spraying, implemented by laser sintering. Commercial NiCrAl powders were plasma sprayed onto 45 Steel substrates to give a bond coat with thickness of ∼100μm. The 600μm thick Al2O3+13%wt.TiO2 based coating was also plasma sprayed on top of the NiCrAl bond coat. With 2.5kw continuous wave CO2 laser, nano-Al2O3 ceramic powders were laser sintered on the based Coatings. The micro structure and chemical composition of the modified Al2O3+13%wt.TiO2 coatings were analyzed by such detection devices as scanning electronic microscope (SEM) and x-ray diffraction (XRD). Microhardness, wear resistance and corrosion resistance of the modified coatings were also tested and compared with that of the unmodified. The results show that the crystal grain size of Al2O3 had no obvious growth. In addition, due to the nanostructured Al2O3 ceramic phases, the coatings exhibited higher microhardness, better wear resistance and corrosion resistance than those unmodified counterparts. The complex process of plasma spraying with laser sintering as a potential effective way of the application of ceramic nano materials was also simply discussed and summarized in the end.


Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 799 ◽  
Author(s):  
Shaopeng Wang ◽  
Lian Zhou ◽  
Changjiu Li ◽  
Zhengxian Li ◽  
Hongzhan Li

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.


2019 ◽  
Vol 58 (1) ◽  
pp. 132-146 ◽  
Author(s):  
Naiming Lin ◽  
Ruizhen Xie ◽  
Jiaojuan Zou ◽  
Jianfeng Qin ◽  
Yating Wang ◽  
...  

AbstractTitanium (Ti) and its alloys have been extensively applied in various fields of chemical industry, marine, aerospace and biomedical devices because of a specific combination of properties such as high strength to weight ratio, exceptional corrosion resistance and excellent biocompatibility. However, friction and wear, corrosion which usually occur on the surfaces of Ti-base components can lead to degradation in both properties and performance. Thermal oxidation (TO) of titanium and its alloys under certain conditions can accomplish significant improvements both in wear resistance and corrosion resistance, without special requirements for substrate geometries. In this review, the studies and applications of TO process in surface damage mitigation titanium and its alloys were reviewed and summarized.


2014 ◽  
Vol 960-961 ◽  
pp. 143-147
Author(s):  
Jun Zhao ◽  
Jian Jun Xi ◽  
Zhi Gang Wang ◽  
Chun Ping Zhao

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.


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