Preparation and Characterisation of CaP-Containing Coating on Magnesium Alloy by Micro-Arc Oxidation and Hydrothermal Treatment

2012 ◽  
Vol 496 ◽  
pp. 383-386
Author(s):  
Li Min Chang ◽  
Dan Dan Xu ◽  
Wei Liu
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Oxide Film ◽  
Hydrothermal Treatment ◽  
Electrochemical Methods ◽  
Dicalcium Phosphate ◽  
Dicalcium Phosphate Dihydrate ◽  
Phosphate Dihydrate ◽  
Micro Arc Oxidation ◽  
Hank’S Solution

Micro-arc oxidation (MAO) together with hydrothermal treatment had been performed to improve the corrosion resistance of magnesium alloy. The oxide films were hydrothermally heated at 150°C for 2h. The morphology of samples were characterized by SEM/EDS. The phase compositions were examined by TF-XRD. The corrosion resistance of the coatings was evaluated by electrochemical methods in Hank’s solution. The MAO films displayed porous and rough structure and were mainly composed of MgO and MgAl2O4. After hydrothermal treatment, a dicalcium phosphate dihydrate (DCPD) coating formed on the oxide film. The corrosion resistance of the MAO film and DCPD coating was increased by about 12 and 40 times higher than that of bare magnesium alloy.

scholarly journals Evolution of the dicalcium phosphate-dihydrate (DCPD) coating created by large amplitude sinusoidal voltammetry (LASV) on corrosion resistance of the ZW3 magnesium alloy in chloride containing environment

2018 ◽  
Vol 62 (1) ◽  
pp. 14-18
Author(s):  
D. Kajánek ◽  
B. Hadzima ◽  
F. Pastorek ◽  
M. Neslušan Jacková
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Large Amplitude ◽  
Electrochemical Impedance ◽  
Dicalcium Phosphate ◽  
Electrochemical Characteristics ◽  
Dicalcium Phosphate Dihydrate ◽  
Electro Deposition ◽  
Cathodic Electrodeposition ◽  
Phosphate Dihydrate

Abstract The contribution is focused on the preparation of coating based on the dicalcium phosphate-dihydrate (DCPD) on the surface of ZW3 magnesium alloy. For the preparation of the coating a cathodic electrodeposition technique called Large Amplitude Sinusoidal Voltammetry (LASV) was used. The DCPD layer was prepared at the temperature of 22 ± 2 °C in electrolyte composed of 0.1M Ca(NO3).4H2O, 0.06 M NH4H2PO4 and H2O2. Electrochemical characteristics were evaluated by electrochemical impedance spectroscopy (EIS) in 0.1M NaCl solution. The obtained data in form of Nyquist plots were analysed by the equivalent circuit method. It is clear from the measured values of polarization resistance Rp that dicalcium phosphate-dihydrate (DCPD) layer prepared by LASV electro-deposition technique improved corrosion resistance of ZW3 alloy in the chosen environment.

Study on Micro-Arc Oxidation Behavior of AZ91 Magnesium Alloy in Aluminate Environmentally Friendly Electrolyte

2020 ◽  
Vol 1003 ◽  
pp. 67-75
Author(s):  
Xian Ming Chen ◽  
Ying Ying Fan
Keyword(s):  
Corrosion Resistance ◽  
Electron Microscope ◽  
Magnesium Alloy ◽  
Oxide Film ◽  
Oxidation Behavior ◽  
Salt Spray ◽  
Alkaline Electrolyte ◽  
Az91 Magnesium Alloy ◽  
Micro Arc Oxidation ◽  
Az91 Magnesium

In aluminate alkaline electrolyte the effect of aluminate on the microstructure and properties and the MAO(micro-arc oxidation) behavior of micro-arc oxide film of AZ91 magnesium alloy was studied. Transmission electron microscope(TEM), energy dispersive spectrum (EDS), X-ray diffraction(XRD), salt spray test and scanning electron microscope(SEM)were used to analyze and characterize the structure and properties of the film. The results show that the concentration of aluminate has an important effect on the tank voltage, corrosion resistance, surface morphology and phase structure of micro-arc oxidation film. The corrosion resistance and film quality of the film were increased first and then decreased, but the surface roughness decreased first and then increased with the increase of aluminate concentration from 5g/L to 30g/L. At our work, the concentration of 10g/L aluminate electrolyte is most favorable to the formation of micro-arc oxide film.

Study on micro-arc oxidation coating of magnetic metal powder composite magnesium alloy

2020 ◽  
Vol 67 (5) ◽  
pp. 501-508
Author(s):  
Zhaowei Su ◽  
Rui Mu ◽  
Yonghui Cui ◽  
Hongda Zhu ◽  
Xuetian Li ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Oxide Film ◽  
Composite Film ◽  
Nickel Powder ◽  
Powder Composite ◽  
Content Type ◽  
Ni Powder ◽  
Micro Arc Oxidation ◽  
Film Layer

Purpose The purpose of this paper is to prepare composite micro-arc oxide coatings with better wear resistance and corrosion resistance. Design/methodology/approach A nickel powder composite micro-arc oxide film was prepared on the surface of the magnesium alloy by the method of organically combining ultra-fine Ni powder with micro arc oxidation film layer. In this experiment, the changes in the corrosion resistance and microstructure of the composite film layer after adding Ni powder were studied, and the effect of the addition of glycerin on the corrosion resistance of the film layer was analyzed. Findings The results show that the ultra-fine nickel powder was successfully prepared by the liquid phase reduction method, and the micro-arc oxidation process was modified under the optimal addition amount. The surface of the micro-arc oxide film made of ultra-fine nickel powder was found by SEM to have smooth surfaces and few holes. According to X-ray diffraction analysis, the phase composition of the micro-arc oxide film layer was Mg, Ni, NiSiO4, MgNi (SiO4) and Mg2SiO4. According to the results of electrochemical tests, the corrosion resistance of the micro-arc oxidation composite film layer was improved after the addition of ultra-fine Ni powder, the corrosion current was greatly reduced and the impedance has been improved. And after adding glycerin, the surface of the film layer becomes denser, and the corrosion resistance of the micro-arc oxide film is significantly improved. Originality/value Through this experimental research, a micro-arc oxide coating of powder composite magnesium alloy was successfully prepared. The corrosion resistance of the micro-arc oxidation film layer has been improved, and certain functions had been given to the micro-arc oxidation composite film, which has increased the application field of magnesium alloys.

Sign in / Sign up

Export Citation Format

Share Document