Effect of Y on Microstructure and Corrosion Resistance of AZ61 Magnesium Alloy

2011 ◽  
Vol 284-286 ◽  
pp. 1529-1532
Author(s):  
Chun Xiang Xu ◽  
Zhi Ling Bai ◽  
Zhen Qiang Wang ◽  
Hui Ju ◽  
Zhi Wei Zhang
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Current ◽  
Second Phase ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
Az61 Magnesium Alloy ◽  
Az61 Alloy ◽  
Refined Microstructure ◽  
The Matrix

The effect of Y addition on the microstructure of AZ61 alloy was investigated by optical microscopy (OM), X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The corrosion behavior of AZ61 alloy with Y addition in 3.5 % NaCl solution was studied by static weight loss and polarization curves corrosion tests. The results show that AZ61 alloy with Y addition can refine grain size of the matrix and alter the distribution of the phase β-Mg17Al12from continuous network morphology transition to small and dispersive distribution along the grain boundary by forming the second phase Al2Y which has a high melting point. In addition, the addition of Y can decrease the corrosion current density of AZ61 magnesium alloy in 3.5% NaCl solution, thereby improving the corrosion resistance of AZ61 magnesium alloy. Results show that AZ61 magnesium alloy with 1.0% Y has the most refined microstructure and the best corrosion resistance.

scholarly journals A microstructural and corrosion resistance study of (Zr, Si, Ti)N-Ni coatings produced through co-sputtering

DYNA ◽  
2018 ◽  
Vol 85 (207) ◽  
pp. 192-197 ◽  
Author(s):  
Estrella Natali Borja-Goyeneche ◽  
Jhon Jairo Olaya-Florez
Keyword(s):  
Corrosion Resistance ◽  
Nickel Content ◽  
Corrosion Current ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Current Densities ◽  
Fcc Phase

This work researches the influence of the nickel content on the structural and anticorrosive properties of ZrSiTiN films deposited by means of reactive co-sputtering on alloys of Ti6Al4V. The morphology and structure were analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the chemical composition was identified via X-ray scattering spectroscopy (EDS). The corrosion resistance was studied using potentiodynamic polarization (PP) tests employing a 3.5% by weight NaCl solution. In the films, an increase of Ni up to 6.97 at% was observed, while in XRD the FCC phase of (Zr, Ti) N was identified, with a mixed orientation in planes (111) and (200), which tended to diminish with the increase of Ni. Finally, with the addition of Ni, the corrosion current densities were reduced from 5.56 𝑥 10−8 to 2.64 𝑥 10−9 𝐴/𝑐m2. The improvement in the corrosion resistance is due to the effect of the Ni on the microstructure of the system (Zr, Ti) N, which can improve the quality of the passive film and prevent crystalline defects and corrosion zones.

Effect of ECAP Pass on Corrosion Behavior of High-Al Content Magnesium Alloys

2013 ◽  
Vol 747-748 ◽  
pp. 270-275
Author(s):  
Qiang Fan ◽  
Wei Liang ◽  
Li Ping Bian ◽  
Man Qing Cheng
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Performance Test ◽  
Corrosion Current ◽  
Second Phase ◽  
Al Content ◽  
Microstructure Observation ◽  
Angular Pressing ◽  
The Matrix ◽  
High Al Content

In view of low strength and poor corrosion resistance of Mg alloys, a Mg-12Al-0.7Si alloy was designed, fabricated and subjected to equal channel angular pressing (ECAP) in order to refine the microstructure. Microstructure observation and electrochemical performance test were conducted to investigate the influence of the microstructural variation subjected to multi-pass ECAP processing on the corrosion behavior of the alloy. The results showed that both α-Mg matrix and β-Mg17Al12of the alloy were significantly refined after processing for different passes (2,4,6,8) through route BC, and the 4-pass ECAPed alloy in 3.5% NaCl solution presents the lowest weight loss, lower corrosion current and higher corrosion potential in the polarization curves. The reason for high corrosion resistance of 4-pass ECAPed alloy and the effects of grain size of the matrix and the particle size, distribution of second phase and dynamic precipitates on corrosion behavior of the alloy were discussed.

Laser Cladding of Zr55Al10Ni5Cu30/SiC Amorphous Composite Coatings on AZ91D Magnesium Alloy for Improvement of Corrosion Resistance

2011 ◽  
Vol 179-180 ◽  
pp. 757-761 ◽  
Author(s):  
Kai Jin Huang ◽  
Hou Guang Liu ◽  
Chang Rong Zhou
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Corrosion Property ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Corrosion Resistance ◽  
Az91d Magnesium Alloy

To improve the corrosion property of magnesium alloys, Zr-based amorphous composite coatings have been fabricated on AZ91D magnesium alloy by laser cladding using mixed powders Zr55Al10Ni5Cu30/SiC. The microstructure of the coating was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion resistance of the coatings was tested in 3.5wt.% NaCl solution. The results show that the coatings mainly consist of amorphous and different crystalline phases. The coatings compared with AZ91D magnesium alloy exhibit good corrosion resistance because of the presence of the amorphous phase in the coatings.

Laser Cladding of Mg65Cu25Y10/SiC Amorphous Composite Coatings on AZ91D Magnesium Alloy for Improvement of Corrosion Resistance

2010 ◽  
Vol 143-144 ◽  
pp. 758-762
Author(s):  
Kai Jin Huang ◽  
Hou Guang Liu ◽  
Chang Rong Zhou
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Corrosion Property ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Corrosion Resistance ◽  
Az91d Magnesium Alloy

To improve the corrosion property of magnesium alloys, Mg-based amorphous composite coatings have been fabricated on AZ91D magnesium alloy by laser cladding using mixed powders Mg65Cu25Y10/SiC. The microstructure of the coating was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion resistance of the coatings was tested in 3.5wt.% NaCl solution. The results show that the coatings mainly consist of amorphous and different crystalline phases. The coatings compared to AZ91D magnesium alloy exhibit good corrosion resistance because of the presence of the amorphous phase in the coatings.

Effect of Heat Treatment on Microstructures and Properties of AZ40M Alloy

2016 ◽  
Vol 849 ◽  
pp. 173-180 ◽  
Author(s):  
Lin Lai ◽  
Kui Zhang ◽  
Ming Long Ma ◽  
Guo Liang Shi
Keyword(s):  
Magnesium Alloy ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Homogenization Treatment ◽  
Homogenization Process ◽  
Β Phase ◽  
Before And After ◽  
The Matrix ◽  
Tensile Fractures ◽  
Tensile Experiment

The influence of two-step homogenization on microstructures and properties of AZ40M magnesium alloy were investigated by the scanning electronic microscopy (SEM), X-ray diffraction analysis (XRD) and tensile experiment. Through comparing the microstructure and mechanical properties of the alloy before and after homogenization treatment, a two-step homogenization process of the semi-continuous casting AZ40M magnesium alloy ingot was determined. The result shows that the as-cast AZ40M alloy mainly contained two kinds of second phase, β-Mg17Al12 and Al8Mn5. Treating at temperature of 380 °C for 8 h as the first step homogenization treatment and then treating at temperature of 420 °C for 20 h as the second step homogenization treatment made the eutectic phase (α-Mg/β-Mg17Al12) completely eliminated and the alloying elements such as Al, Zn distributed uniformly. Al8Mn5 is the residual second phase in the homogenized AZ40M alloy. During the homogenization process, the β-phase dissolved which made the content of Al increased in the matrix. The decomposition of β-phase benefits the tensile strength and elongation of the alloy. The tensile fractures of as-cast and homogenization alloys are characteristic of ductile fracture.

Role of Aluminium on the Microstructure and Corrosion Behaviour of Magnesium Prepared by Powder Metallurgy Method

2020 ◽  
Vol 17 (3) ◽  
pp. 8206-8213
Author(s):  
J. Alias
Keyword(s):  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Corrosion Behaviour ◽  
Corrosion Current ◽  
Optical Microscope ◽  
High Reactivity ◽  
Aluminium Content ◽  
Powder Metallurgy Method ◽  
X Ray Diffraction ◽  
Promising Development

Much research on magnesium (Mg) emphasises creating good corrosion resistance of magnesium, due to its high reactivity in most environments. In this study, powder metallurgy (PM) technique is used to produce Mg samples with a variation of aluminium (Al) composition. The effect of aluminium composition on the microstructure development, including the phase analysis was characterised by optical microscope (OM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The mechanical property of Mg sample was performed through Vickers microhardness. The results showed that the addition of aluminium in the synthesised Mg sample formed distribution of Al-rich phases of Mg17Al12, with 50 wt.% of aluminium content in the Mg sample exhibited larger fraction and distribution of Al-rich phases as compared to the 20 wt.% and 10 wt.% of aluminium content. The microhardness values were also increased at 20 wt.% and 50 wt.% of aluminium content, comparable to the standard microhardness value of the annealed Mg. A similar trend in corrosion resistance of the Mg immersed in 3.5 wt.% NaCl solution was observed. The corrosion behaviour was evaluated based on potentiodynamic polarisation behaviour. The corrosion current density, icorr, is observed to decrease with the increase of Al composition in the Mg sample, corresponding to the increase in corrosion resistance due to the formation of aluminium oxide layer on the Al-rich surface that acted as the corrosion barrier. Overall, the inclusion of aluminium in this study demonstrates the promising development of high corrosion resistant Mg alloys.

Mechanical properties and wear-corrosion resistance of a new compound extrusion process for magnesium alloy AZ61

2020 ◽  
Vol 62 (4) ◽  
pp. 395-399
Author(s):  
Jiehui Liu ◽  
Hongjun Hu ◽  
Yang Liu ◽  
Dingfei Zhang ◽  
Zhongwen Ou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Magnesium Alloy ◽  
Equal Channel Angular Extrusion ◽  
Extrusion Process ◽  
Corrosion And Wear ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Manufacturing Method ◽  
Az61 Magnesium Alloy

Abstract Compound extrusion (CE) is a newly developed plastic deformation technique which combines direct extrusion (DE) with a two-pass equal channel angular extrusion (ECAE). This paper focuses on the strength, ductility and anti-corrosion properties of an NaCl solution at certain concentrations and the wear-resistance of dry sliding AZ61 magnesium alloy prepared by CE and DE. It is found that the strength and elongation of the AZ61 alloy prepared by CE are enhanced because of grain refinement. Furthermore, AZ61 magnesium alloy made by CE displays higher corrosion and wear resistance than that prepared by DE. Experimental results prove that CE is a prospective manufacturing method for improving the mechanical properties, anti-corrosion and anti-wear of AZ61 magnesium alloy.

Research on Corrosion Resistance of AZ91D Magnesium Alloy Coated with Epoxy Resin

2011 ◽  
Vol 686 ◽  
pp. 292-299
Author(s):  
Yong Gang Li ◽  
Ying Hui Wei ◽  
Li Feng Hou ◽  
Yun Tian ◽  
Li Jing Yang
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Adhesion Force ◽  
Die Casting ◽  
Corrosion Current ◽  
Scratch Test ◽  
Organic Coating ◽  
Thin Wall ◽  
Scanning Method ◽  
Az91d Magnesium Alloy

The corrosion resistance of a 1~2mm thick AZ91D magnesium alloy die-casting coated with epoxy varnish after phosphatizing was tested. Zinc phosphating solution was used. In the experiment, uniform paint was obtained by dipping method. Scratch test showed that the adhesion force between the coating and matrix is excellent. Within the test range the optimal phosphating temperature and time are 50°C and 1 min tested by dynamic potential scanning method. With the organic coating the corrosion current density decreased 3 orders of magnitude, the polarization resistance increased 3 orders of magnitude. The coated specimens were immersed in10% H2SO4, 10% NaOH and acetone for 10 days, respectively. The results showed that blistering did not occur on the paint films. This work illustrated that the simple zinc phosphating process combined with simple organic coating can meet the corrosion resistance requirements of thin-wall die casting magnesium components that require higher quality appearance.

scholarly journals Effect of Cooling Rate at the Eutectoid Transformation Temperature on the Corrosion Resistance of Zn-4Al Alloy

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1703
Author(s):  
Marzena M. Lachowicz ◽  
Robert Jasionowski
Keyword(s):  
Corrosion Resistance ◽  
Cooling Rate ◽  
Cast Alloy ◽  
Corrosion Current ◽  
Electrochemical Studies ◽  
Eutectoid Transformation ◽  
Nacl Solution ◽  
Α Phase ◽  
Initial Stage ◽  
Alloy Microstructure

The main purpose of this work was to experimentally determine the effect of the cooling rate during the eutectoid transformation on the corrosion resistance of a hypoeutectic Zn-4Al cast alloy in 5% NaCl solution. This was considered in relation to the alloy microstructure. For this purpose, metallographic and electrochemical studies were performed. It was found that the faster cooling promoted the formation of finer (α + η) eutectoid structures, which translated into a higher hardness and lower corrosion current density. In the initial stage of corrosion processes the eutectoid structure in the eutectic areas were attacked. At the further stages of corrosion development, the phase η was dissolved, and the α phase appears to be protected by the formation of corrosion products.

Preparation and characterization emulsion of PANI-TiO2 nanocomposite and its application as anticorrosive coating

2015 ◽  
Vol 35 (6) ◽  
pp. 597-603 ◽  
Author(s):  
Mohsen Khademian ◽  
Hossein Eisazadeh
Keyword(s):  
Electron Microscopy ◽  
Colloidal Particles ◽  
Aqueous Media ◽  
Corrosion Current ◽  
Ammonium Persulfate ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Definition Of

Abstract Emulsion nanoparticles of polyaniline (PANI) were synthesized in the aqueous media by using hydroxylpropylcellulose (HPC) as a stabilizer and ammonium persulfate as an oxidant in the presence of TiO2 with nanometer size. New poly(vinyl acetate) (PVAc) coating over carbon steel was prepared by addition of emulsion nanoparticles in different concentrations (1%, 2% and 1.5%) in PVAc as the major matrix. The Tafel plot records were used for the definition of potential and corrosion current (Icorr). Nanoparticles were characterized and compared by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By adding TiO2, the thermal stability of the nanocomposite increased. A small size of colloidal particles prevented the precipitation of conducting polymer particles and led to better dispersion of nanocomposites in the matrix of the PVAc binder; therefore, the paint was homogeneous and anticorrosion properties of the coating increased. According to the results, 1.5% of PANI-TiO2 nanocomposite in PVAc has a much lower Icorr in NaCl aqueous solution and 2% of PANI-TiO2 nanocomposite in PVAc has the best corrosion protection in HCl.

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