Process Characteristics and Experiment on Micro Arc Oxidation of Light Metals

2013 ◽  
Vol 690-693 ◽  
pp. 2067-2070
Author(s):  
Yi Wang ◽  
Hong You Li ◽  
Mao Lin Shi
Keyword(s):  
Stainless Steels ◽  
Ceramic Coating ◽  
Tribological Behavior ◽  
Influence Factors ◽  
Surface Characteristics ◽  
Light Metals ◽  
X Ray ◽  
Process Characteristics ◽  
Eds Analysis ◽  
Micro Arc Oxidation

Micro arc oxidation (MAO) is a relatively new method of surface treatments which has been used to improve the mechanical and tribological behavior of light metals. Due to the ceramic coating generated by MAO, light metals can be used more widely. The fundamental of MAO and the influence factors of MAO process are discussed here. The surface characteristics of aluminum, titanium, magnesium, Zirconium and stainless steels have been improved by MAO. Scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS) were used to study the surface morphology and the elemental composition of the MAO coating. The EDS analysis of the coating shows the elements in the electrolyte and oxygen have incorporated into the coating.

Pore Morphology in MAO Produced Oxide Film Modified by Magnesium Integration

2011 ◽  
Vol 493-494 ◽  
pp. 539-544
Author(s):  
Guler Ungan ◽  
F. Ak Azem ◽  
Ahmet Cakir
Keyword(s):  
Bone Formation ◽  
Composite Layer ◽  
Magnesium Content ◽  
Implant Surface ◽  
X Ray ◽  
Eds Analysis ◽  
Fast Bone ◽  
Micro Arc Oxidation ◽  
Characterization Studies ◽  
Scanning Electron

Ti6Al4V alloy commonly used in human body for load bearing prosthesis was coated by micro arc oxidation (MAO) with magnesium rich TiO2 oxide. Since the presence of magnesium in bone tissues is known to promote bone formation and proliferation in physiological environment, its integration with TiO2 on implant surface could bring about a bioactivity for a fast bone formation and proliferation. The formation of a composite layer consisting of Mg integrated TiO2 by MAO process was carried out in an electrolyte with different magnesium content. The characterization studies of these coatings were performed by using X-ray diffractometry (XRD), scanning electron microscopy (SEM) coupled with EDS analysis and XP2 surface profilometry.

Preparation of Micro-Arc Oxidation Ceramic Coating and Application in Degradation Rhodamine B

2014 ◽  
Vol 687-691 ◽  
pp. 4210-4213
Author(s):  
Hai Tao Bu ◽  
Zhao Hua Jiang ◽  
Zhong Ping Yao
Keyword(s):  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
Degradation Rate ◽  
Ceramic Coating ◽  
Amorphous State ◽  
Electrolyte System ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Fenton System

A ceramic coating grows on the surface of Q235 carton steel in situ by the micro-arc oxidation method and the silicate electrolyte system; and the phase composition, surface topography and elementary composition of the ceramic coating are analyzed by X-ray diffractometer (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (EDS). The results show that the ceramic coating growing on the surface of Q235 carton steel in situ presents an irregular porous structure; and the electrolyte and the element in the basal body exist in the ceramic coating in the form of amorphous state. And then, the author degrades the rhodamine B solution by the home-made ceramic coating and H2O2Fenton system, so that the degradation rate of the rhodamine B solution can reach 97%; and meanwhile, the degradation rate is not reduced along the increased using times.

Fabrication and Degradation Properties of Ca/P Contained Micro-Arc Oxidation Coating on Pure Magnesium

2020 ◽  
Vol 12 (5) ◽  
pp. 755-759 ◽  
Author(s):  
Ying-Xue Teng ◽  
Fang Liu ◽  
Cheng-Yang Li ◽  
Zhen Xu ◽  
Jing Guo
Keyword(s):  
Degradation Rate ◽  
Ceramic Coating ◽  
Medical Application ◽  
Pure Magnesium ◽  
X Ray Diffraction ◽  
Surface Protection ◽  
X Ray ◽  
Deposition Parameters ◽  
Micro Arc Oxidation ◽  
Degradation Properties

Nowadays, Mg based metals attract much attention because of their biodegradability and bioactivity. However, over fast degradation rate still restrict their widely medical application. Therefore, surface protection treatment is necessary to control the degradation rate. In this study, a ceramic coating was successfully fabricated on pure magnesium by Micro-arc oxidation (MAO) method. The surface quality was dramatically influenced by deposition parameters such as voltage and frequency. The composition of the sample was characterized by X-ray diffraction (XRD) and the surface morphology was characterized by scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The degradation behavior of MAO coated Mg was investigated. It is expected that pure Mg with MAO coating can be used for the orthopedic application especially as bone screw.

The Effect of Oxidized Time to Structure and Composition of Micro-Arc Oxidization Ceramic Coating of Pure Titanium

2016 ◽  
Vol 852 ◽  
pp. 984-991
Author(s):  
Lin Xu ◽  
Jian Ning Ding ◽  
Zhen Huang ◽  
Ni Na Han ◽  
Xiao Jing Xu ◽  
...  
Keyword(s):  
Ceramic Coating ◽  
Pure Titanium ◽  
Relative Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Opposite Trend ◽  
Micro Arc Oxidation ◽  
Porous Oxide ◽  
3D Profilometer ◽  
Scanning Electron

The porous oxide TiO2 ceramic coating containing Ca and P is fabricated on the surface of pure titanium in the electrolyte of C4H6CaO4-NaH2PO4 by micro-arc oxidation (MAO) method. Scanning electron microscopy (SEM) and 3D profilometer are used to observe difference between morphology of coating surface under condition of different oxidized time. Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) are used to discuss the effect of oxidized time to the ratio of Ca/P and phase composition of ceramic coating. Results indicate that the oxidized time has a little effect on structure and composition of MAO ceramic coating of pure titanium. After modified with MAO, pure titanium is rough and porous on its surface, its average aperture, porosity and roughness enlarge as oxidized time extends. The increase of oxidized time makes the ratio of Ca/P and the relative content of rutile TiO2 increases, but the relative content of anatase TiO2 shows opposite trend.

The Effect of Current Density to Surface Morphology and Component of Micro-Arc Oxidization Ceramic Coating of Pure Titanium

2016 ◽  
Vol 852 ◽  
pp. 992-999 ◽  
Author(s):  
Lin Xu ◽  
Jian Ning Ding ◽  
Zhen Huang ◽  
Ni Na Han ◽  
Xiao Jing Xu ◽  
...  
Keyword(s):  
Current Density ◽  
Mixed Crystal ◽  
Ceramic Coating ◽  
Pure Titanium ◽  
Film Surface ◽  
X Ray Diffraction ◽  
Average Pore ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
3D Profilometer

The ceramic coating containing anatase TiO2 and rutile TiO2 is fabricated on the surface of pure titanium in the electrolyte of C4H6CaO4-NaH2PO4 by micro-arc oxidation (MAO) method. The effect of different current density to microscopic structure, elemental composition and phase components of Ceramic Coating are studied with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), 3D profilometer and etc. Results indicate that the ceramic coating on pure titanium by micro-arc oxidation is a porous mixed crystal structure which is mainly composed of such elements as Ti, O, Ca and P. With current density increasing, the average pore diameter and roughness on film surface first increase and then decrease, the porosity increases, the ratio of Ca/P then decreases, the relative content of anatase TiO2 increases and that of rutile TiO2 decreases.

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

The interaction of a manganese-oxidising bacterium as part of a biofilm growing on distribution pipe materials

2000 ◽  
Vol 41 (4-5) ◽  
pp. 295-300 ◽  
Author(s):  
F. Murdoch ◽  
P.G. Smith
Keyword(s):  
Biofilm Formation ◽  
Bacterial Activity ◽  
Confocal Laser ◽  
Pipe Surface ◽  
X Ray ◽  
Pseudomonas Spp ◽  
Eds Analysis ◽  
Large Clusters ◽  
Pipe Materials ◽  
Confocal Laser Microscope

The deposition of manganese within a biofilm growing on the surface of high-density polyethlene (HDPE) and polyvinychloride (PVC) was studied over a period of four months. The manganese rich water used in the study was inoculated with a manganese oxidising Pseudomonas spp. The level of Mn2+ in the water was monitored and was found to decrease as the biofilm formation increased. This was confirmed by energy dispersive X-ray spectroscopy (EDS) analysis which showed the detection of manganese was dependent on the presence of a biofilm. After two months a 100% removal of Mn2+ was observed in all the flasks inoculated by the Pseudomonas spp. and manganese micro-nodules, the formation of which were reported in Murdoch and Smith (1999), were being formed in large clusters across the surfaces of both the HDPE and PVC. The manganese peak area from the EDS spectrum analysis of the micro-nodules was significantly larger than was measured in the biofilm when these micro-nodules were absent. The scanning confocal laser microscope (SCLM) images of three-week samples showed high bacterial activity around areas where manganese micro-nodules were starting to form on the pipe surface.

Detecting Critical Crevice Temperature for Duplex Stainless Steels in Chloride Solutions

CORROSION ◽  
2011 ◽  
Vol 67 (2) ◽  
pp. 025004-1-025004-7 ◽  
Author(s):  
D. Han ◽  
Y. Jiang ◽  
B. Deng ◽  
L. Zhang ◽  
J. Gao ◽  
...  
Keyword(s):  
Stainless Steels ◽  
Crevice Corrosion ◽  
Electrochemical Method ◽  
Duplex Stainless Steels ◽  
Good Reproducibility ◽  
X Ray ◽  
Initiation Step ◽  
Critical Pitting Temperature ◽  
Preferential Dissolution ◽  
Scanning Electron

Abstract A simple and rapid electrochemical method for the evaluation of crevice corrosion in duplex stainless steels (DSS) is described. Three types of DSS—namely, UNS S32101, UNS S31803, and UNS S32750—were tested in 1 mol/L sodium chloride (NaCl) solutions. Results showed good reproducibility with a typical standard deviation of below 3°C. The critical pitting temperature (CPT) for the same specimens was also investigated in 1 mol/L NaCl solutions. An approximately 20°C decrease from CPT to critical crevice temperature (CCT) was observed and subsequently explained. Then, the morphologies of crevice corrosion were studied using scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM/EDS) method. The SEM/EDS study revealed that the ferrite phase was the site where preferential dissolution took place at the initiation step of crevice corrosion, which was in accordance with the prediction by calculating the critical crevice index. Moreover, repassivation was detected with the development of crevice corrosion. The reason was clarified by combining the results obtained with a successful diffusion model, and eventually the crevice corrosion progress was illustrated schematically.

scholarly journals Effect of Molybdenum Content on the Corrosion and Microstructure of Low-Ni, Co-Free Maraging Steels

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 852
Author(s):  
Asiful H. Seikh ◽  
Hossam Halfa ◽  
Mahmoud S. Soliman
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Microstructural Analysis ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Alloying Element ◽  
X Ray ◽  
Maraging Steels ◽  
Eds Analysis ◽  
Electroslag Refining

Molybdenum (Mo) is an important alloying element in maraging steels. In this study, we altered the Mo concentration during the production of four cobalt-free maraging steels using an electroslag refining process. The microstructure of the four forged maraging steels was evaluated to examine phase contents by optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. Additionally, we assessed the corrosion resistance of the newly developed alloys in 3.5% NaCl solution and 1 M H2SO4 solution through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Furthermore, we performed SEM and energy-dispersive spectroscopy (EDS) analysis after corrosion to assess changes in microstructure and Raman spectroscopy to identify the presence of phases on the electrode surface. The microstructural analysis shows that the formation of retained austenite increases with increasing Mo concentrations. It is found from corrosion study that increasing Mo concentration up to 4.6% increased the corrosion resistance of the steel. However, further increase in Mo concentration reduces the corrosion resistance.

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