Effect of K2Cr2O7 on Anti-Biofouling Properties of MAO Coating on Titanium Alloy Surface

2014 ◽  
Vol 513-517 ◽  
pp. 173-176
Author(s):  
Qiang Yao ◽  
Si Rong Yu ◽  
Hong Chao Chu
Keyword(s):  
Titanium Alloy ◽  
Ceramic Coating ◽  
Average Diameter ◽  
Ceramic Coatings ◽  
Immersion Test ◽  
Alloy Surface ◽  
Concentration Increase ◽  
Composite Electrolyte ◽  
Aluminium Titanate ◽  
Micro Arc Oxidation

Ceramic coatings were prepared on Ti6Al4V alloy surface by applying micro-arc oxidation (MAO) technique. K2Cr2O7 was added into the aluminate-based composite electrolyte for preparing coatings containing Cr. The coatings' morphologies were observed using SEM and their composition was characterized using XRD and EDS. Research shows that the working voltage of MAO reaction was lower after adding K2Cr2O7. The SEM pictures show that the average diameter of micropores decreased while the number increased as the K2Cr2O7 concentration increase. The coatings contain rutile TiO2, anatase TiO2, aluminium titanate (Al2TiO5) and Cr0.222Ti0.778O1.889 (when adding 1.5g/L K2Cr2O7). The EDS results show that all coatings contained Cr after adding K2Cr2O7 into electrolyte. After immersion test for half year, results show that ceramic coating containing chromium has lower anti-biofouling properties than the substrate.

Preparation and Performance of Ceramic Coatings Formed by Micro Arc Oxidation on Titanium Alloy

2008 ◽  
Vol 375-376 ◽  
pp. 323-327
Author(s):  
Ying Xue Yao ◽  
Li Qun Li ◽  
Jian Jun Xi
Keyword(s):  
Titanium Alloy ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Dense Layer ◽  
X Ray Diffraction ◽  
Technological Parameters ◽  
Tc4 Titanium Alloy ◽  
Micro Arc Oxidation ◽  
Anodic Voltage ◽  
And Performance

The effect of technological parameters on MAO ceramic coating were investigated through the technique of micro-arc oxidation (MAO) on TC4 titanium alloy and. Microstructure and morphology of coatings were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result shows that electric parameters and compositions of the electrolyte have notable effects on the growth of MAO ceramic coatings. The cathodic and anodic voltage rise gradually with the oxidation time increasing. The growth rate of ceramic coating is fast at the beginning, and then turns slowly. The ceramic coatings can be divided into three layers from interior to exterior, such as the transition layer, the dense layer and the porous layer. The coating is mainly composed of rutile and anatase and combined with the substrate firmly. The ceramic coating’s composition in inner and outer layers appears quite different. The ceramic coating on titanium alloy is of excellent performance on anti-attrition and anti-corrosion.

Variable Parameter Processes of Micro-Arc Oxidation for Aluminium Alloy

2011 ◽  
Vol 704-705 ◽  
pp. 1273-1278
Author(s):  
Cheng Gao ◽  
Jin Yong Xu ◽  
Xuan Yi Shi ◽  
Ya Juan Liu ◽  
Jing Chun Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Wear Rate ◽  
Ceramic Coating ◽  
Early Stage ◽  
Variable Parameter ◽  
Ceramic Coatings ◽  
Constant Current ◽  
Constant Voltage ◽  
Micro Arc Oxidation ◽  
The Way

In micro-arc oxidation process, ceramic coating had a rapid growth all along by the way of constant current oxidation, and ceramic coating had a low roughness by the way of constant voltage oxidation. But few research focus on the mixed control process of constant current oxidation and constant voltage oxidation. In this paper we propose a variable parameter process that can combine the advantages of constant current and constant voltage oxidation for the first time. The growth kinetics of different technics was analyzed according to the change law of current and voltage. Surface topographs of ceramic coating were observed using scanning electron microscopy (SEM). The friction tests were carried out using a self-made friction tester. The results show that ceramic coating has an upper growth rate and a low roughness by the process of constant current+constant voltage oxidation. The ceramic coating has a high growth rate by process of constant voltage+constant current oxidation. The results of friction test indicate that the wear rate and roughness of ceramic coating are positive correlation at early stage of friction. While the ceramic coatings treated by different technics have the close wear rate at stable friction stage, which embodies the inner layer of ceramic coating has a well antiwear behavior.

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.

Laser Cladding of Fluoridated Hydroxyapatite Coatings on Titanium Alloy: Preparation and Characterization

2014 ◽  
Vol 487 ◽  
pp. 204-209 ◽  
Author(s):  
Ge Yang ◽  
Shu Hui Hu ◽  
Yuan Liu ◽  
An Guo Huang
Keyword(s):  
Titanium Alloy ◽  
Laser Cladding ◽  
Raw Materials ◽  
Ceramic Coatings ◽  
Immersion Test ◽  
Structure And Properties ◽  
Fluoridated Hydroxyapatite ◽  
Activity Phase ◽  
Hydroxyapatite Coatings ◽  
Simulated Body Fluid Immersion

In this research, Fluoridated hydroxyapatite bio-ceramic coatings were produced by laser cladding on the titanium alloy with hydroxyapatite and CaF2 as raw materials. The microstructures and phase constitutions of coatings were characterized by OM, SEM, EDS and XRD, the mechanical properties was investigated by micro-hardness and simulated body fluid immersion test. The results indicated that Fluoridated hydroxyapatite bio-ceramic coatings with anticipated structure and properties were achieved successfully by laser cladding on the titanium alloy. Compared with CO2 laser, the FHA coatings prepared by fiber laser had better deposition of biological activity phase.

Influences of Copper Complexes on the Properties of MAO Ceramic Coating on Titanium Alloy Surface

2014 ◽  
Vol 788 ◽  
pp. 138-143 ◽  
Author(s):  
Qiang Yao ◽  
Si Rong Yu ◽  
Hong Chao Chu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Titanium Alloy ◽  
Copper Complexes ◽  
Ceramic Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminium Titanate ◽  
Black Coating ◽  
Scanning Electron

The present work focuses on the influence of copper complexes in the MAO electrolyte on the structure and wears resistance of ceramic coating on the surface of titanium alloy. The coatings composition and the morphologies were characterized using X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). It is shown that the working voltage of MAO reaction was lower after adding [Cu (NH3)4]2+than adding EDTA-Cu. The color of ceramic coating is black (prepared in the electrolyte with [Cu (NH3)4]2+) and brown (prepared in the electrolyte with EDTA-Cu). The black coating contained rutile TiO2, anatase TiO2and aluminium titanate (Al2TiO5), while the brown coating contained rutile and anatase only. The black coating which contained CuO compound was found to outperform brown coating in wear resistance.

A Comparison on Ceramic Coating Formed on AM50 Alloy by Micro-Arc Oxidation in Two Electrolytes

2007 ◽  
Vol 546-549 ◽  
pp. 575-578 ◽  
Author(s):  
Hui Zhao ◽  
Zhen Liu ◽  
Zhong Han
Keyword(s):  
Growth Rate ◽  
Surface Roughness ◽  
Magnesium Alloy ◽  
Porous Layer ◽  
Barrier Layer ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Micro Arc Oxidation ◽  
Am50 Alloy ◽  
Phosphate Electrolyte

Characteristics of ceramic coatings on AM50 magnesium alloy by micro-arc oxidation in silicate and phosphate electrolytes have been investigated in this study. This study reveals that the thickness of the ceramic coatings increases with the treated time in both electrolytes, the growth rate of ceramic layer in phosphate is faster than that in silicate electrolyte. The surface roughness of the ceramic coating formed in phosphate electrolyte is higher than that formed in silicate electrolyte. The coatings formed in silicate, containing a thicker inner barrier layer and a thinner outer porous layer, consist of MgO, Mg2SiO4 and MgSiO3 phases. For the coatings formed in phosphate, the outer porous layer is thicker than the inner layer, it consist mainly of MgO and MgAlO4 phases.

Preparation and Performance of Micro-Arc Oxidation Ceramic Coating of Titanium Alloy in Low Current Density

2011 ◽  
Vol 335-336 ◽  
pp. 708-712
Author(s):  
Jian Jun Xi ◽  
Jun Zhao ◽  
Guo Jun Niu
Keyword(s):  
Titanium Alloy ◽  
Friction Coefficient ◽  
Surface Morphology ◽  
Current Density ◽  
Ceramic Coating ◽  
Low Power Consumption ◽  
Bipolar Pulse ◽  
Phosphate Silicate ◽  
Micro Arc Oxidation ◽  
And Performance

In this paper, Three types of electrolyte (phosphate, silicate, aluminum) are considered to make preparation for micro-arc oxidation coatings on titanium alloy by bipolar pulse MAO oxidation power with low power consumption (density of current less than 1A/dm2). Treated by micro-arc oxidation, dense micro-arc oxidation ceramic coating is formed on titanium alloy. Surface morphology and friction coefficient of MAO coating is analyzed. The research on the effect of NaF on ablation of MAO coating is prepared, which guides the configuration of the electrolyte later.

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.

Growth Process and Corrosion Resistance of Ceramic Coatings of Micro-Arc Oxidation on Mg-Nd Magnesium Alloys

2011 ◽  
Vol 189-193 ◽  
pp. 891-896
Author(s):  
Yong Chun Guo ◽  
Jian Ping Li ◽  
Jin Shan Li ◽  
Ping Wang
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Magnesium Alloys ◽  
Phase Structure ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Ceramic Surface ◽  
Linear Regularity ◽  
Micro Arc Oxidation

The regulation of ceramic coating formed by micro-arc oxidation on Mg-3Nd-0.2Zn-0.4Zr(wt%) magnesium alloys has been investigated by SEM and XRD. The relation of phase structure and corrosion resistance of MgO coating formed by micro-arc oxidation in different growth stages has been analyzed. The results have shown that in the initial stages of micro-arc oxidation, the growth of coating accords with linear regularity, which is the stage of anodic oxidation controlled by electrochemical polarization. With elongated treated time and increased thickness of the coating, the growth of coating accords with parabolic and linear regularity, which is the stage of micro-arc oxidation. In the stage of local arc light, the slope of parabola and thickness of loose coating increases so that the growth rate enhances. The phase structure of loose coating is mainly composed of MgSiO3 and the phase structure of compact ceramic coating is mainly composed of MgO. From the stage of micro-arc oxidation to local arc light, corrosion resistance of coating firstly increase and then decrease. The satisfied corrosion resistance corresponds to the coating time ranging from 7 to15minutes.The addition of rare earth elements in the magnesium alloy reduces the amount of smooth areas on ceramic surface. So the ceramic coating becomes more compact and smooth. The rare earth elements don’t form independent phases in ceramic coating but affect the relative proportion of constitution phases, resulting in the reduction of intermixed magnesium phase and the increase of the MgO and MgSiO3 phases.

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