Influence of HF-SCG Immersion Treatment on Corrosion Resistance of the Ultrasonic Micro-Arc Oxidation Bio-Coating on Pure Magnesium

2014 ◽  
Vol 633 ◽  
pp. 402-405
Author(s):  
Mu Qin Li ◽  
Jiang Liu ◽  
Jun Gang Li ◽  
Ding Sen Cai ◽  
Yong Hui Zhao
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Ceramic Coatings ◽  
Pure Magnesium ◽  
Electrolyte System ◽  
Order Of Magnitude ◽  
Micro Arc Oxidation ◽  
Compound Coatings

Ceramic coatings were fabricated on pure magnesium in silicate electrolyte system by ultrasonic micro-arc oxidation (UMAO) process, and then silica sol (CSG) and HF-CSG treatment were carried out on micro-arc oxidation coatings. The corrosion potential (Ecorr) and corrosion current density (Icorr) of the compound coatings were analyzed by electrochemical corrosion workstation. The corrosive morphology of the coatings was observed by scanning electron microscopy (SEM). Results showed that the Ecorr of the coating with CSG and HF-CSG treatment increased by 55 mV and 69 mV respectively in comparison with that of single UMAO coating, and its Icorr reduced an order of magnitude, which had enhanced the corrosion resistance.

EFFECT OF KOH ON MICRO-ARC OXIDATION COATINGS OF 2A12 ALUMINUM ALLOYS IN CH3COONa–Na2WO4 ELECTROLYTE

2014 ◽  
Vol 21 (02) ◽  
pp. 1450026
Author(s):  
ZHAO QING LIN ◽  
HUI JUN YU ◽  
SI YU HE ◽  
YI NING HE ◽  
CHUAN ZHONG CHEN
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Scratch Test ◽  
Ceramic Coatings ◽  
X Ray Diffraction ◽  
Electrolyte System ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Scanning Electron

The ceramic coatings were prepared on 2A12 alloy by micro-arc oxidation in CH 3 COONa – Na 2 WO 4 electrolyte system with different concentration of KOH added. The effects of KOH in this electrolyte on micromorphology, phase compositions, adhesion and corrosion resistance of the coatings were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), scratch test and electrochemistry workstation. The results show that KOH has a significant influence on the surface morphology, which can make the surface smoother. The adhesion of the coating becomes stronger with the increase of KOH in the electrolyte. The corrosion resistance of the coated specimen increases a lot compared with that of the substrate. And the lowest corrosion current density (I corr ) of the coating prepared in the electrolyte with KOH is about three orders of magnitude lower than that of the substrate.

Double Sealing of Ultrasonic Micro-Arc Oxidation Coating on Pure Magnesium by Nano-SiO2 Particles and SiO2 Sol Sealing Agent

2014 ◽  
Vol 1030-1032 ◽  
pp. 48-51
Author(s):  
Wei Wei Sun ◽  
Mu Qin Li ◽  
Yan Gao ◽  
Jiang Liu
Keyword(s):  
Corrosion Resistance ◽  
Bone Growth ◽  
Corrosion Current ◽  
Pure Magnesium ◽  
Infrared Spectrometry ◽  
Nano Sio2 ◽  
Micro Arc Oxidation ◽  
Sio2 Particles ◽  
Si Content ◽  
Sealing Coating

A double sealing coating was prepared on ultrasonic micro-arc oxidized pure magnesium substrate by adding nano-SiO2 particles as additive in the plating solution and coating SiO2 sol as sealing agent. The bonding characters of SiO2 sol was analyzed by Fourier transformed infrared spectrometry (FTIR). The compositions and morphology of seal coating were characterized by energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM), respectively. The corrosion resistance of the micro-arc oxidized and the sealed pure magnesium substrate were studied. The results showed that the Si content increased gradually with the addition of nano-SiO2 particles and the SiO2 sol sealing. It was benefit to create bioactive MgSiO3, which promoted the bone growth. The double sealed pure magnesium had a self-corrosion potential shifted positively by 60mV as well as a self-corrosion current density decreased by a half in a 3.5wt% NaCl solution, showing good corrosion resistance.

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.

The Preparation of Coatings with Codepositon Plating on A3 Steel and its Corrosion Resistance

2010 ◽  
Vol 150-151 ◽  
pp. 1034-1038
Author(s):  
Shang Dong Chen ◽  
Ting Sun ◽  
Hong Nian
Keyword(s):  
Corrosion Resistance ◽  
Polarization Resistance ◽  
Polarization Effect ◽  
Corrosion Potential ◽  
Steel Substrate ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Plain Carbon Steel ◽  
Cathode Polarization ◽  
Electrochemical Corrosion Behavior

A new method for preparation of coatings with codeposition plating on the ordinary A3 steel and heat treatment later. Research the coatings on electrochemical corrosion behavior variation in Q-sun. Results show that corrosion potential shuffle, corrosion current density reduced nearly two number magnitudes value, polarization resistance increased, the cathode polarization effect enhanced obviously in polarization curves, and self-corrosion current reduced, impedance increased twenty times in alternating current impedance atlas than A3 steel substrate without coatings. It was indicated that the coating improve effectively the corrosion resistance of plain carbon steel.

The Effect of n-TiO2 on Corrosion and Biological Activity of Biocoatings Coated by Ultrasound Micro-Arc Oxidation on Pure Magnesium

2014 ◽  
Vol 633 ◽  
pp. 418-421 ◽  
Author(s):  
Chen Ma ◽  
Yan Gao ◽  
Li Jie Qu ◽  
Mu Qin Li ◽  
Jin Long Yue ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Biological Activity ◽  
Magnesium Alloy ◽  
Simulated Body Fluid ◽  
Surface Morphology ◽  
Body Fluid ◽  
Electrochemical Corrosion ◽  
Order Of Magnitude ◽  
Micro Arc Oxidation ◽  
Different Content

In order to improve the corrosion resistance and bioactivity of magnesium alloy coated by ultrasound micro-arc oxidation (UMAO), different content of n-TiO2 was added into silicate electrolyte. Electrochemical corrosion and simulated body fluid (SBF) soaking were conducted, and the surface morphology, phase structure and composition also were analyzed. The results indicated that Ecorr and Icorr of UMAO biocoatings with n-TiO2 increased and decreased an order of magnitude with increase of n-TiO2, respectively. The corrosion resistance of coatings with adding 4.8g/L n-TiO2 into electrolyte was the best. After soaking in SBF, the samples increased loose weight firstly and then increased weight to form Mg3Ca (CO3)4, Mg10Cl (OH)18·5H2O and Na4Mg2(PO4) ·2H2O new phases and Mg, MgO, MgSiO3 were still exit, which showed that good bioactivity of the UMAO coatings with n-TiO2.

scholarly journals The Preparation and Properties of the Brown Film by Micro-arc Oxidized on In-Situ TiB2/7050Al Matrix Composites

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 615
Author(s):  
Cunjuan Xia ◽  
Jie Huang ◽  
Jiongming Tao ◽  
Shuyang Wang ◽  
Ling Cai ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Alkaline Electrolyte ◽  
Matrix Composites ◽  
Al Composite ◽  
White Film ◽  
Alkaline Electrolytes ◽  
Micro Arc Oxidation

The brown or grayish-white color films were prepared by the micro-arc oxidation (MAO) method on in-situ TiB2/7050Al composites using these alkaline electrolytes with/without KMnO4 as an additive. The microstructure, elemental composition, chemical state and corrosion behavior have been investigated by the microstructure characterizations and electrochemistry measurements on the MAO films comparatively. The results indicated that a brown film was obtained via adding KMnO4 into the alkaline electrolyte. The coloration mechanism of the brown color can be ascribed to the existence of MnO inside the film. Furthermore, the initiation of corrosion to the Al composite was intensively hindered by the brown MAO film. Compared with the Al substrate and grayish-white film, the brown MAO film exhibited the elevated corrosion potential and reduced corrosion current. Therefore, the brown film has presented an optimized corrosion resistance for the composite.

scholarly journals Corrosion Resistance of X5CrNi18-10 Stainless Steel

2017 ◽  
Vol 62 (4) ◽  
pp. 2101-2106
Author(s):  
M. Kciuk ◽  
S. Lasok
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Polarization Resistance ◽  
Corrosion Potential ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Eds Microanalysis ◽  
Scanning Electron

AbstractThe paper presents the influence of heat treatment on the structure and corrosion resistance of X5CrNi18-10 steel. To determine the structure which has been obtained after heat treatment the methods of light and scanning electron microscopy with EDS microanalysis were used. The electrochemical corrosion properties of the investigated steel were studied in 3.5% NaCl solution using potentiodynamic polarization tests. Basing on the registered curves, the corrosion current, polarization resistance and corrosion potential were determined. The corrosion tests were followed by fractographic researches.

Preparation and Corrosion Behaviour of Micro-Arc Oxidation Coating on Ti6Al4V Alloy

2012 ◽  
Vol 621 ◽  
pp. 117-120
Author(s):  
Xiu Zhou Lin ◽  
Min Gong ◽  
Zhao Hua Wang ◽  
Peng Zhang
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Corrosion Current ◽  
Ti6al4v Alloy ◽  
Oxidation Time ◽  
Oxidation Treatment ◽  
X Ray ◽  
Micro Arc Oxidation

Micro-arc oxidation (MAO) coatings were prepared on Ti6Al4V alloys surface by using self-made micro-arc oxidation equipment. Its characterizations were systematically detected by Vickers hardness tester, scanning electron microscope (SEM), X-ray diffractometer (XRD) and X-ray fluorescence spectrometer (XFS). Corrosion behaviour of MAO coating and Ti6Al4V alloy in Hank's simulated body fluid were studied comparatively using electrochemical workstations and salt spray test chamber. The experimental results indicated that the MAO coating, with rough surface, high hardness and typical porous ceramic structure, is mainly consist of anatase and rutile TiO2 phase. Micro-arc oxidation treatment can significantly improve corrosion resistance of Ti6Al4 alloy, and the corrosion resistance of the coating is observably affected by the coating technology. During the micro-arc oxidation treatment, the thickness of the coating increases with the increase of oxidation time, which induce that the corrosion potential and polarization resistance of the coating increase, and the corrosion current reduce. Simultaneously, the thicker the coating, the higher the pitting resistance is. On the other hand, under the same oxidation time, as the current density increases during micro-arc oxidation treatment, the corrosion potential of the coating positive shifts, and the corrosion current reduces.

Influence of In Situ MgO Coating on Corrosion Resistance of Pure Magnesium in Normal Saline

2009 ◽  
Vol 79-82 ◽  
pp. 1039-1042
Author(s):  
Li Chen Zhao ◽  
Chun Xiang Cui ◽  
Shuang Jin Liu ◽  
Yu Min Qi
Keyword(s):  
Corrosion Resistance ◽  
Normal Saline ◽  
Oxide Coating ◽  
Corrosion Current ◽  
Pure Magnesium ◽  
Heat Treated ◽  
Order Of Magnitude ◽  
Porous Oxide ◽  
Biological Performance

Magnesium and its alloys are potential biodegradable materials due to their outstanding biological performance, but their poor corrosion resistance greatly limits their applications as bone implants. This paper investigates the influence of in situ magnesium oxide coating on corrosion resistance of pure magnesium in normal saline. It was discovered by SEM that rough and porous oxide coatings were obtained on the surface of the pure magnesium after heat-treated at 400~500°C and the samples were severely corroded after immersion in 0.9 wt.% NaCl solution for 3 days. It also showed that the weight loss rates of the treated pure magnesium (TPM) samples were about 5~6 times higher than that of the untreated pure magnesium (UPM) sample. Electrochemical measurements showed that the corrosion current density (icorr) of the TPM samples was one order of magnitude higher than that of the UPM sample.

scholarly journals Evaluation of Structure and Corrosion Behavior of FeAl Alloy after Crystallization, Hot Extrusion and Hot Rolling

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2041
Author(s):  
Janusz Cebulski ◽  
Dorota Pasek ◽  
Bartosz Chmiela ◽  
Magdalena Popczyk ◽  
Andrzej Szymon Swinarew ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Hot Rolling ◽  
Cast Alloy ◽  
Rolling Direction ◽  
Extrusion Direction ◽  
Electrochemical Corrosion ◽  
Hot Extrusion ◽  
Corrosion Current ◽  
Plastic Working ◽  
Ingot Axis

The paper presents the results of tests on the corrosion resistance of Fe40Al5Cr0.2TiB alloy after casting, plastic working using extrusion and rolling methods. Examination of the microstructure of the Fe40Al5Cr0.2TiB alloy after casting and after plastic working was performed on an Olympus GX51 light microscope. The stereological relationships of the alloy microstructure in the state after crystallization and after plastic working were determined. The quantitative analysis of the structure was conducted after testing with the EBSD INCA HKL detector and the Nordlys II analysis system (Channel 5), which was equipped with the Hitachi S-3400N microscope. Structure tests and corrosion tests were performed on tests cut perpendicular to the ingot axis, extrusion direction, and rolling direction. As a result of the tests, it was found that the crystallized alloy has better corrosion resistance than plastically processed material. Plastic working increases the intensity of the electrochemical corrosion of the examined alloy. It was found that as-cast alloy is the most resistant to corrosion in a 5% NaCl compared with the alloys after hot extrusion and after hot rolling. The parameters in this study show the smallest value of the corrosion current density and corrosion rate as well as the more positive value of corrosion potential.

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