Influences of Zinc Content and Solution Heat Treatment on Microstructure and Corrosion Behavior of Mg-Zn Binary Alloys

CORROSION ◽  
10.5006/3672 ◽  
2020 ◽  
Author(s):  
Dinh Pham ◽  
Sachiko Hiromoto ◽  
Equo Kobayashi
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Volume Fraction ◽  
Galvanic Corrosion ◽  
Zinc Content ◽  
Eutectic Cell ◽  
Zn Content ◽  
Cast Alloys

The influences of Zn content and heat treatment on microstructure and corrosion behavior of Mg-xZn (x=1, 3, 5 and 7 wt.%) alloys were studied. (α-Mg + MgZn) eutectic cells and Zn-segregated regions were formed in the as-cast alloys. The Zn-rich phases acted as micro-cathodes in galvanic corrosion. Volume fraction of the Zn-rich phases increased with Zn content of the as-cast alloys, leading to a decrease in corrosion resistance. The corrosion rate of the as-cast alloys increased by 4 times with an increase of the volume fraction of eutectic cell from 0.07 vol.% of Mg-1Zn alloy to 2.18 vol.% of Mg-5Zn alloy. The corrosion rate of Mg-7Zn alloy with 2.87 vol% eutectic cells was 2 times higher than that of Mg-5Zn alloy. The Zn-rich phases dissolved by the T4 treatment and only the T4-treated Mg-7Zn alloy obviously showed eutectic cells of 1.73 vol.%. The polarization resistance (Rp) of the T4-treated Mg-1, 3 and 5Zn alloys was 2-10 times higher than that of the as-cast alloys. The T4-treated Mg-7Zn showed similar Rp to the as-cast Mg-5Zn alloy. Consequently, the volume fraction of Zn-rich phases dominated the corrosion resistance of Mg-xZn alloys.

The Influence of Sn Addition on the Corrosion Behavior of Mg-5Al-1Zn Alloy

2009 ◽  
Vol 620-622 ◽  
pp. 153-156 ◽  
Author(s):  
Kyung Chul Park ◽  
Byung Ho Kim ◽  
Jong Jin Jeon ◽  
Yong Ho Park ◽  
Ik Min Park
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Volume Fraction ◽  
Secondary Phases ◽  
Nacl Solution ◽  
High Hydrogen ◽  
Hydrogen Overvoltage ◽  
Mg2sn Phase ◽  
Superior Corrosion Resistance

In the present work, the effect of Sn addition on the corrosion behavior of Mg–5Al–1Zn alloys was investigated. Microstructure, potentiodynamic polarization and immersion tests were carried out in 3.5% NaCl solution of pH 7.2 to estimate the corrosion behavior of AZ51 alloys with and without Sn addition. Mg17Al12 and Mg2Sn phases were mainly precipitated in inter-dendrite structures. With increasing the Sn content, the volume fraction of the Mg2Sn phase was increased and coarsening tendency was observed. The corrosion resistance was increased by Sn addition. Especially, the AZ51-5wt.%Sn alloy characterized the superior corrosion resistance among the four alloys. The Sn is known for a high hydrogen overvoltage and the secondary phases effectively formed the network structure, resulting in a drastically decreasing corrosion rate of AZ51 alloy.

Heat Treatment Influence on the Corrosion Resistance of a Cu-Al-Fe-Mn Bronze

2018 ◽  
Vol 69 (5) ◽  
pp. 1055-1059 ◽  
Author(s):  
Mariana Ciurdas ◽  
Ioana Arina Gherghescu ◽  
Sorin Ciuca ◽  
Alina Daniela Necsulescu ◽  
Cosmin Cotrut ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Structural Changes ◽  
Heating Temperature ◽  
Galvanic Corrosion ◽  
Cooling Water ◽  
Open Circuit ◽  
Water Quenching ◽  
Heat Treated ◽  
Different Temperatures

Aluminium bronzes are exhibiting good corrosion resistance in saline environments combined with high mechanical properties. Their corrosion resistance is obviously confered by the alloy chemical composition, but it can also be improved by heat treatment structural changes. In the present paper, five Cu-Al-Fe-Mn bronze samples were subjected to annealing heat treatments with furnace cooling, water quenching and water quenching followed by tempering at three different temperatures: 200, 400 and 550�C. The heating temperature on annealing and quenching was 900�C. The structure of the heat treated samples was studied by optical and scanning electron microscopy. Subsequently, the five samples were submitted to corrosion tests. The best resistance to galvanic corrosion was showed by the quenched sample, but it can be said that all samples are characterized by close values of open-circuit potentials and corrosion potentials. Concerning the susceptibility to other types of corrosion (selective leaching, pitting, crevice corrosion), the best corrosion resistant structure consists of a solid solution, g2 and k compounds, corresponding to the quenched and 550�C tempered sample.

scholarly journals Corrosion Behavior and Galvanic Corrosion Resistance of WC and Cr3C2 Cermet Coatings in Madeira River Water

2021 ◽  
Author(s):  
Leonardo Augusto Luiz ◽  
Juliano de Andrade ◽  
Camila Melo Pesqueira ◽  
Irene Bida de Araújo Fernandes Siqueira ◽  
Gustavo Bavaresco Sucharski ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
River Water ◽  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Cermet Coatings ◽  
Madeira River

scholarly journals Effect of Structural Modification on Corrosion Behavior of Hypo Eutectic Al-Si Alloy

2018 ◽  
Vol 778 ◽  
pp. 16-21
Author(s):  
Muhammad Mansoor ◽  
Muhammad Kamran Yaseen ◽  
Shaheed Khan
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Earth Metal ◽  
Alloy System ◽  
Eutectic Phase ◽  
Al Alloy ◽  
General Corrosion ◽  
Corrosion Properties ◽  
Unmodified Alloy ◽  
Cast Alloys

Al-Si eutectic cast alloys are widely used in aeronautical and automobile industries where significantly high strength, toughness and wear resistance are required. This class of cast alloys exhibit relatively low corrosion resistance in brine environments. The mechanical properties of the alloy system mainly depend upon the shape of Si rich eutectic phase, which mainly has acicular geometry. In present research, the effect of modified microstructure of 12 wt. % Si-Al alloy on corrosion behavior was studied. The needle like Si rich eutectic phase was modified to disperse spherical structure using rare earth metal halides. The corrosion rate and pitting behavior of modified and unmodified alloy were evaluated in 3.5% NaCl solution by general corrosion for calculated time. It was observed that the corrosion rate and pitting tendency of modified alloy had been appreciably reduced as compare to unmodified alloy. The improvement of corrosion properties were the attributes of changed morphology and distribution of Si rich eutectic phase.

scholarly journals Effect of Heat Treatment and Sulfuric Acid Anodization on Corrosion Resistance of Aluminum Alloy (AA7075)

2021 ◽  
Vol 40 (1) ◽  
pp. 56-62
Author(s):  
M. Abdullahi ◽  
L.S. Kuburi ◽  
P.T. Zubairu ◽  
U. Jabo ◽  
A.A. Yahaya ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Polarization Resistance ◽  
Testing Machine ◽  
Palm Kernel ◽  
Engine Oil ◽  
Micro Hardness

This paper, studied the effect of heat treatment and anodization on corrosion resistance of aluminum alloy 7075 (AA7075), with a view to improving its corrosion resistance. Microstructure and micro hardness of the anodic film of the samples were studied with the aid of optical metallurgical microscope and automated micro hardness testing machine. Linear polarization methods were used to assess the corrosion behaviour of the alloy in 0.5M HCl. The microstructure of the annealed sample showed formation of dendrites while precipitation hardened samples in palm kernel oil and SAE 40 engine oil showed precipitates of MgZn2. The SEMS result showed pores and micro cracks on the surfaces of the anodized samples, with the as cast and anodized sample in sulfuric acid exhibiting most compact with few pores. The as cast and sulfuric acid anodized sample shows highest micro hardness value of 205.33 HV, while the least value of 150.67 HV was recorded in sample precipitation hardened in SAE 40 engine oil and anodized in sulfuric acid. Analysis of the potentiodynamic polarization data and curves showed a linear relationship (decrease in icorr, decreases the corrosion rate) between current density and the corrosion rate in all the samples. Higher polarization resistance of 15.093 Ω/cm2 was recorded by the as cast and Sulfuric acid (SA) anodized sample while the precipitation treated in SAE 40 engine oil plus SA anodized sample recorded lowest polarization resistance of 5.2311 Ω/cm2. Heat treatment alone improves corrosion resistance of AA 7075 in 0.5 M HCl solution but heat treatment plus SA anodization does not improve corrosion resistance in the same environment.

scholarly journals The Corrosion Behavior of Sputter-Deposited Nanocrystalline W-Cr Alloys in Nacl and NaohaSolutions

1970 ◽  
Vol 25 ◽  
pp. 53-61
Author(s):  
Minu Basnet ◽  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Chromium Content ◽  
Open Circuit ◽  
Nacl Solution ◽  
Corrosion Rates ◽  
Naoh Solution ◽  
Order Of Magnitude ◽  
Sputter Deposited

The corrosion behavior of the sputter-deposited nanocrystalline W-Cr alloys wasstudied in 0.5 M NaCl and alkaline 1 M NaOH solutions at 25°C, open to air usingimmersion tests and electrochemical measurements. Chromium metal acts synergisticallywith tungsten in enhancing the corrosion resistance of the sputter-deposited W-Cr alloys soas to show higher corrosion resistance than those of alloy-constituting elements in both 0.5M NaCl and 1 M NaOH solutions. In particular, the nanocrystalline W-Cr alloys containing25-91 at% chromium showed about one order of magnitude lower corrosion rates (that is,about 1-2 × 10-3 mm.y-1) than those of tungsten and chromium metals even for prolongedimmersion in 0.5 M NaCl solution at 25°C. On the other hand, the corrosion rate of thesputter-deposited W-Cr alloys containing 25-75 at % chromium was decreased significantlywith increasing chromium content and showed lowest corrosion rates (that is, 1.5-2.0 × 10-3 mm.y-1) after immersed for prolonged immersion in 1 M NaOH solution. The corrosion ratesof these nanocrystalline W-(25-75)Cr alloys are nearly two orders of magnitude lower thanthat of tungsten and more than one order of magnitude lower corrosion rate than that ofsputter-deposited chromium metal in 1 M NaOH solution. The corrosion-resistant of all theexamined sputter-deposited W-Cr alloys in 0.5 M NaCl solution is higher than in alkaline 1M NaOH solution at 25°C. Open circuit potentials of all the examined W-Cr alloys areshifted to more noble direction with increasing the chromium content in the alloys afterimmersion for 72 h in both 0.5 M NaCl and 1 M NaOH solutions at 25°C, open to air.Keywords: Sputter deposition, nanocrystalline W-Cr alloys, corrosion test, electrochemicalmeasurement, NaCl and NaOH solutions.DOI:  10.3126/jncs.v25i0.3300Journal of Nepal Chemical Society Volume 25, 2010 pp 53-61

EFFECT OF FRICTION STIR PROCESSING ON CORROSION BEHAVIOR OF CAST AZ91C MAGNESIUM ALLOY

2019 ◽  
Vol 26 (06) ◽  
pp. 1850213 ◽  
Author(s):  
BEHZAD HASSANI ◽  
RUDOLF VALLANT ◽  
FATHALLAH KARIMZADEH ◽  
MOHAMMAD HOSSEIN ENAYATI ◽  
SOHEIL SABOONI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Friction Stir Processing ◽  
Potentiodynamic Polarization ◽  
Passive Layer ◽  
Friction Stir ◽  
T6 Heat Treatment ◽  
Az91c Magnesium Alloy

The corrosion behavior of as-cast AZ91C magnesium alloy was studied by performing friction stir processing (FSP) and FSP followed by solution annealing and then aging. Phase analysis, microstructural characterization, potentiodynamic polarization test and immersion tests were carried out to relate the corrosion behavior to the samples microstructure. The microstructural observations revealed the breakage and dissolution of coarse dendritic microstructure as well as the coarse secondary [Formula: see text]-Mg[Formula: see text]Al[Formula: see text] phase which resulted in a homogenized and fine grained microstructure (15[Formula: see text][Formula: see text]m). T6 heat treatment resulted in an excessive growth and dispersion of the secondary phases in the microstructure of FSP zone. The potentiodynamic polarization and immersion tests proved a significant effect of both FSP and FSP followed by T6 on increasing the corrosion resistance of the cast AZ91C magnesium alloy. Improve in corrosion resistance after FSP was attributed to grain refinement and elimination of segregations and casting defects which makes more adhesive passive layer. Increase in volume fraction of precipitations after T6 heat treatment is determined to be the main factor which stabilizes the passive layer at different polarization values and is considered to be responsible for increasing the corrosion resistance.

scholarly journals Effect of Minor Alloying Elements on the Corrosion Behavior of Fe40Al in NaCl-KCl Molten Salts

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
G. Salinas ◽  
J. G. Gonzalez-Rodriguez ◽  
J. Porcayo-Calderon ◽  
V. M. Salinas-Bravo ◽  
M. A. Espinoza-Medina
Keyword(s):  
Weight Loss ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Molten Salts ◽  
Electrochemical Techniques ◽  
The Other ◽  
Type Stainless Steel ◽  
Waste Gasification

The hot corrosion behavior of Fe40Al intermetallic alloyed with Ag, Cu, Li, and Ni (1–5 at.%) in NaCl-KCl (1 : 1 M) at 670°C, typical of waste gasification environments, has been evaluated by using polarization curves and weight loss techniques and compared with a 304-type stainless steel. Both gravimetric and electrochemical techniques showed that all different Fe40Al-base alloys have a much higher corrosion resistance than that for stainless steel. Among the different Fe40Al-based alloys, the corrosion rate was very similar among each other, but it was evident that the addition of Li decreased their corrosion rate whereas all the other elements increased it. Results have been explained in terms of the formation and stability of an external, protective Al2O3layer.

Effect of Zn Content on the Microstructure and Corrosion Behaviour of Mg-7Y-0.6Zr Alloy

2013 ◽  
Vol 765 ◽  
pp. 612-617
Author(s):  
Jian Li Wang ◽  
Jian Ping Li ◽  
Ping Wang ◽  
Yong Chun Guo ◽  
Zhong Yang
Keyword(s):  
Corrosion Rate ◽  
Corrosion Potential ◽  
Volume Fraction ◽  
Corrosion Behaviour ◽  
Secondary Phase ◽  
Immersion Test ◽  
Electrochemical Tests ◽  
Method Effect ◽  
Zn Content ◽  
Mould Casting

Mg-7Y-0.6Zr-xZn (x = 0, 0.5, 1.0, 1.5, 2.0, 2.5, wt.%) alloys were prepared by the metal mould casting method. Effect of Zn content on the microstructures and corrosion behaviour were investigated. Results showed that microstructures were refined and volume fraction of secondary phase Mg24(YZn)5 was increased with increasing addition of Zn element. Results of electrochemical tests demonstrated that the corrosion potential of Mg-7Y-0.6Zr alloy was about -1.77 V, and, with addition of 0.5~2.0 wt.% Zn element, corrosion potential moved to more positive values than that of Mg-7Y-0.6Zr alloy. Mg-7Y-0.6Zr-0.5Zn alloy possessed the most positive corrosion potential of -1.53 V. The results of immersion test with different time also indicated that corrosion rate could be decreased by addition of 0.5~2.0 wt.% Zn, and Mg-7Y-0.6Zr-0.5Zn alloy exhibited the lowest corrosion rate.

Microstructures and Various Properties of Hot-Extruded Mg-Zr-Ca Alloys for Biomedical Applications

2012 ◽  
Vol 232 ◽  
pp. 162-166 ◽  
Author(s):  
Ying Long Zhou ◽  
Dong Mei Luo ◽  
Yun Cang Li ◽  
Cui'e Wen ◽  
Peter D. Hodgson
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Biomedical Applications ◽  
Hot Extrusion ◽  
X Ray Diffraction ◽  
Cast Alloys ◽  
Orthopedic Applications ◽  
Potential Use ◽  
Compressive Tests

The microstructures, mechanical properties, corrosion behavior, and biocompatibility of hot-extruded Mg-Zr-Ca alloys have been investigated for potential use in orthopedic applications. The microstructures of the alloys are examined by X-ray diffraction analysis and optical microscopy. The mechanical properties of Mg-Zr-Ca alloys are determined from compressive tests, the corrosion behavior is studied using immersion tests, and biocompatibility is evaluated by cell growth factor using osteoblast-like SaOS2 cell. The experimental results indicate that the hot-extruded alloys have much higher compressive strength than the as-cast alloys and the human bone, and can offer good mechanical properties for orthopedic applications. The hot-extrusion significantly enhances corrosion resistance of the alloys. Among the alloys, the hot-extruded Mg-0.5Zr-1Ca and Mg-1Zr-1Ca alloys possess good combination of mechanical properties, corrosion resistance, and biocompatibility, suggesting that they have a great potential to be good candidates for orthopedic applications.

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