scholarly journals Effect of Manganese on Microstructure and Corrosion Behavior of the Mg-3Al Alloys

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 460 ◽  
Author(s):  
Yao ◽  
Liu ◽  
Zeng ◽  
Li ◽  
Lei ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Intermetallic Phase ◽  
Localized Corrosion ◽  
Experimental Investigations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Tests ◽  
Microstructure Observation

Microstructure and corrosion behavior of the Mg-3Al-xMn (x = 0, 0.12, 0.21, 0.36, 0.45) (hereafter in wt.%) alloys were experimentally investigated by electron probe microanalysis (EPMA), scanning electron microscope equipped with energy dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), electrochemical, and hydrogen evolution tests. A new self-constructed Mg-Al-Mn-Fe thermodynamic database was used to predict the solidification paths of the alloys. The addition of Mn showed no grain refinement in the cast Mg-3Al alloys. According to the microstructure observation, Al-Fe phases were observed in the non-Mn-added alloy, while Al8Mn5(LT) (Al8Mn5 in low temperature) became the main intermetallic phase in the Mn-added alloys, and the amount increased gradually with the Mn addition. The τ–Al0.89Mn1.11 phase with lower Al/(Fe + Mn) ratio was observed in the alloys with 0.36 and 0.45 wt.% Mn content. According to the electrochemical tests, all five alloys showed localized corrosion characteristics in 3.5 wt.% NaCl solution. Compared with the Mg-3Al alloy, the corrosion resistance of Mn-added alloys were significantly improved and increased gradually with the Mn addition, which was due to the variation of Al-containing intermetallic compounds. The present experimental investigations and thermodynamic calculations confirmed the mechanism that the increasing amount of Al8Mn5(LT) with Mn addition could encapsulate the B2-Al(Mn,Fe) phase with higher Fe. Therefore, it could prevent this detrimental phase from contacting magnesium matrix, thus suppressing micro-galvanic corrosion and improving corrosion resistance gradually.

scholarly journals New Zn3Mg-xY Alloys: Characteristics, Microstructural Evolution and Corrosion Behavior

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2505
Author(s):  
Catalin Panaghie ◽  
Ramona Cimpoeșu ◽  
Bogdan Istrate ◽  
Nicanor Cimpoeșu ◽  
Mihai-Adrian Bernevig ◽  
...  
Keyword(s):  
Galvanic Corrosion ◽  
Intermetallic Phase ◽  
Young Modulus ◽  
Induction Melting ◽  
X Ray Diffraction ◽  
Medical Field ◽  
Pure Zinc ◽  
X Ray ◽  
Knowing That ◽  
Master Alloys

Zinc biodegradable alloys attracted an increased interest in the last few years in the medical field among Mg and Fe-based materials. Knowing that the Mg element has a strengthening influence on Zn alloys, we analyze the effect of the third element, namely, Y with expected results in mechanical properties improvement. Ternary ZnMgY samples were obtained through induction melting in Argon atmosphere from high purity (Zn, Mg, and Y) materials and MgY (70/30 wt%) master alloys with different percentages of Y and keeping the same percentage of Mg (3 wt%). The corrosion resistance and microhardness of ZnMgY alloys were compared with those of pure Zn and ZnMg binary alloy. Materials were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), linear and cyclic potentiometry, and immersion tests. All samples present generalized corrosion after immersion and electro-corrosion experiments in Dulbecco solution. The experimental results show an increase in microhardness and indentation Young Modulus following the addition of Y. The formation of YZn12 intermetallic phase elements with a more noble potential than pure Zinc is established. A correlation is obtained between the appearance of new Y phases and aggressive galvanic corrosion.

scholarly journals Effects of Laser Scanning Speed on Microstructure, Microhardness, and Corrosion Behavior of Laser Cladding Ni45 Coatings

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Yanxin Qiao ◽  
Jie Huang ◽  
Ding Huang ◽  
Jian Chen ◽  
Wen Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Primary Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microhardness Distribution ◽  
Laser Scanning Speed ◽  
The One

The effects of laser scanning speed on the microstructure, microhardness, and corrosion behavior of Ni45 coatings were investigated by using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness, and electrochemical measurements. The results showed that increasing laser scanning speed promotes the transformation from planar crystals to dendrites and refines the grains concurrently. The γ-(Ni, Fe), FeNi3, and M23(C,B)6 are identified as the primary phase composition in the Ni45 coatings regardless of the laser scanning speed. Thereinto, the formation and growth of M23(C,B)6 precipitates can be inhibited with increasing laser scanning speed due to the higher cooling rate, which affects the microhardness distribution and corrosion resistance of the coating. On the one hand, the microhardness of the whole coating presents a downtrend with increasing laser scanning speed due to the reduction of M23(C,B)6 phase. On the other hand, the corrosion resistance in 0.5 M NaCl solution is improved to some extent at higher laser scanning speed because the less precipitation of M23(C,B)6 reduces the depletion of Cr around the precipitates. In contrast, all the coatings exhibit undifferentiated but poor corrosion resistance in the highly corrosive 0.5 M NaCl + 0.5 M H2SO4 solution.

Effects of Alkaline Treatment on Corrosion Behavior of Biodegradable Magnesium

2015 ◽  
Vol 1125 ◽  
pp. 441-444 ◽  
Author(s):  
Mahtab Assadian ◽  
Mohd Hasbullah Idris ◽  
Mohammad Mahdi Taheri ◽  
Mostafa Rezazadeh Shirdar ◽  
Davood Almasi
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Barrier Layer ◽  
Room Temperature ◽  
Ph Value ◽  
Alkaline Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Biomaterial Application ◽  
Biodegradable Magnesium

Corrosion behavior of Magnesium substrate were investigated after NaOH treatment in different concentrations (1, 5, and 10 Molar) and duration of (10 min, 30 min, 1 h, 3 h, 6 h and 24 h) at room temperature to be utilized in biomaterial application. Creation of Mg(OH)2 barrier layer after treatment enhanced corrosion resistance. X-Ray diffraction (XRD) was conducted to detect the existence of barrier layer. Potentiodynamic polarization and immersion tests were evaluated the corrosion behavior of Magnesium in Kokubo simulated body fluid (SBF). It is found that Magnesium treated by 1M NaOH for 30 min reveals higher corrosion resistance. In addition this investigation indicates that pH value of Kokubo SBF, strongly influenced by different time and concentration of alkaline treatment

General Corrosion Behavior of N06022 in Super Concentrated Brines at Temperatures Higher than 100°C

2008 ◽  
Vol 1124 ◽  
Author(s):  
Raul B. Rebak
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Short Term ◽  
Corrosion Resistant ◽  
Electrochemical Tests ◽  
Alloy 22 ◽  
Nickel Based Alloy ◽  
Anions And Cations

AbstractAlloy 22 (N06022) is a highly corrosion resistant nickel based alloy. Extensive research has been conducted in the last eight years on the corrosion behavior of Alloy 22, mainly regarding its resistance to localized corrosion. Less attention has been paid to the general corrosion resistance in highly concentrated brines that may result from the deliquescence of salts contained in dust. Salts such as mixtures of NaCl, KCl, CaCl2, NaNO3, and KNO3 may deliquesce at temperatures above 100°C through absorption of moisture from the air. Electrochemical tests were used to assess the general corrosion behavior of Alloy 22 in brines with chloride and nitrate concentrations ranging from 8 molal to 100 molal in the temperature range 100 to 160°C. The effect of mixed anions and cations was also studied. Results show that, even for short-term immersion periods, the corrosion rate of Alloy 22 in high temperatures super concentrated brines is generally below 10 μm/year.

Corrosion Behavior of SiCp/6061 Al Metal Matrix Composites

CORROSION ◽  
1991 ◽  
Vol 47 (10) ◽  
pp. 741-753 ◽  
Author(s):  
H. Sun ◽  
E. Y. Koo ◽  
H. G. Wheat
Keyword(s):  
Metal Matrix Composites ◽  
Corrosion Behavior ◽  
Metal Matrix ◽  
Electrochemical Techniques ◽  
Microscopic Analysis ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Tests ◽  
Analysis Techniques

Abstract The corrosion behavior of silicon carbide/aluminum (SiCp/Al) metal matrix composites was studied in chloride solution by means of electrochemical techniques, scanning electron microscopy (SEM), Auger electron spectroscopy (AES), energy dispersive spectroscopy (EDS), and X-ray diffraction. The materials under investigation were powder metallurgy (P/M) processed 6061 Al reinforced with increasing amounts of SiC particles (15 to 40 vol%). Electrochemical tests such as potentiodynamic polarization were done in 0.035, 0.35, and 3.5% NaCl solutions that were open to air, aerated, or deaerated to observe overall corrosion behavior. In addition, pit morphology was observed after anodic polarization to a number of potentials. It was seen that the corrosion potentials did not vary greatly or show definite trends in relation to the amounts of SiCp reinforcement. However, the degree of corrosion increased with increasing SiCp content and the presence or absence of oxygen as well as the concentration of the NaCl solution did affect corrosion potentials. Microscopic analysis techniques were used to study the corroded samples and the extensive pitting and exfoliation of the surfaces. X-ray diffraction was used to identify the compounds on the surface of the corroded samples as well as the flakes due to exfoliation.

scholarly journals Effect of Argon-Oxygen Mixing Gas during Magnetron Sputtering on TiO2 Coatings

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
N. Madaoui ◽  
L. Bait ◽  
K. Kheyar ◽  
N. Saoula
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Magnetron Sputtering ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Potentiodynamic Polarization Curves ◽  
Morphology And Structure ◽  
Steel Substrates

A reactive r.f magnetron sputtering method was used to deposit titanium dioxide coating on stainless steel substrates without intentional heating or biasing. The purpose of this work is given to study the argon-oxygen mixing gas on the corrosion behavior of TiO2 coatings. The morphology and structure of the coatings were studied by X-ray diffraction (XRD). Potentiodynamic polarization was used to study the corrosion behavior of the coatings. The results obtained from potentiodynamic polarization curves showed that TiO2 coatings possessed higher corrosion resistance than uncoated substrate.

Corrosion Behavior and Microstructure of Pd Ions Doped Cerium Conversion Coating on AA2219-T87 Aluminum Alloy

2015 ◽  
Vol 1090 ◽  
pp. 79-83
Author(s):  
Yan Hong He ◽  
Zhen Duo Cui ◽  
Xian Jin Yang ◽  
Sheng Li Zhu ◽  
Zhao Yang Li ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Composite Coatings ◽  
Corrosion Current ◽  
Conversion Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Excellent Corrosion Resistance

In this paper, Pd ions doped cerium conversion coating (CeCC/Pd) was deposited on AA2219-T87 aluminum alloy by electroplating. The microstructure and composition of the coating were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS). Corrosion behavior of AA2219-T87 aluminum alloy with the coating was investigated in 3.5wt.% NaCl solution at the room temperature. XRD and XPS results indicate the existence of cerium-oxide and palladium-oxide in the CeCC/Pd. Polarization curves show that the CeCC/Pd exhibits excellent corrosion resistance. The corrosion current density of the CeCC/Pd decreases by two orders of magnitude compared with the CeCC. The improvement of corrosion resistance would be attributed to the small grain size, good compactness and adhesive strength of the composite coatings.

Study on Microstructure and Corrosion Behavior of Ag-Cu-Zn-Ni Alloys

2011 ◽  
Vol 311-313 ◽  
pp. 2132-2137 ◽  
Author(s):  
Fu Xiang Huang ◽  
Ping Yin ◽  
Yong Hong Xu ◽  
Ying Zhang
Keyword(s):  
Corrosion Behavior ◽  
Energy Dispersive Spectrum ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Silver Alloys ◽  
X Ray ◽  
Electrochemical Tests ◽  
Ni Alloys ◽  
Second Phases ◽  
Electronic Microscope

Potentiodynamic electrochemical tests and surface analysis technics, such as scanning electronic microscope (SEM), energy dispersive spectrum (EDS) and X-ray diffraction analysis (XRD), were applied to investigate the microstructure and corrosion behavior of Ag-Cu-Zn-Ni alloys in Na2S solution. The results reveal that the α-Ag phase is the main matrix of the studied silver alloys. The second phase of Ag-4Cu-0.3Ni and Ag-3Cu-Zn-0.3Ni/Ag-6Cu-Zn-0.3Ni are respectively CuNi and CuNi(Zn) phases. The second phases of Ag-6Cu-Zn-0.3Ni are well-distributed, which leads to an improvement in the corrosion resistance in Na2S solution.

PREPARATION OF GRAYISH BLACK FILM ON AM50 MAGNESIUM ALLOY BY CHEMICAL CONVERSION–MICRO-ARC OXIDATION

2016 ◽  
Vol 24 (01) ◽  
pp. 1750012 ◽  
Author(s):  
ZHONGCAI SHAO ◽  
FEIFEI ZHANG ◽  
QINGFANG ZHANG ◽  
LI YANG ◽  
XIAOYI SHEN
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Composite Film ◽  
Chemical Conversion ◽  
X Ray Diffraction ◽  
Black Film ◽  
X Ray ◽  
Electrochemical Tests ◽  
Micro Arc Oxidation ◽  
Optimum Formula

The grayish black film was prepared on AM50 magnesium alloy with a new method which combined chemical conversion with micro-arc oxidation (MAO). The optimum formula of chemical conversion was obtained by L9(34) orthogonal test. Meanwhile, the morphology, structure, composition and corrosion resistance of films were analyzed by scanning electron microscopy (SEM), energy spectrum analysis (energy dispersive X-ray spectroscopy (EDS)), X-ray diffraction (XRD), electrochemical tests and CuSO4 drip experiment. The results indicated that Mo element was introduced into the MAO film by chemical conversion pretreatment. The surface of composite film was smooth and compact. The main phase composition of the composite film were SiO2, Mo9O[Formula: see text], MgSiO[Formula: see text] Mg2SiO4 and Mo9O[Formula: see text] was identified to be responsible for giving color to the film. The corrosion resistance of the grayish black film was improved obviously.

scholarly journals Effect of Cast Defects on the Corrosion Behavior and Mechanism of UNS C95810 Alloy in Artificial Seawater

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1790 ◽  
Author(s):  
Xu Zhao ◽  
Yuhong Qi ◽  
Jintao Wang ◽  
Zhanping Zhang ◽  
Jing Zhu ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Laser Scanning ◽  
Galvanic Corrosion ◽  
Corrosion Current ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Testing ◽  
Alloy Microstructure

To study the effect of cast defects on the corrosion behavior and mechanism of the UNS C95810 alloy in seawater, an investigation was conducted by weight loss determination, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), X-ray diffraction (XRD) and electrochemical testing of the specimen with and without cast defects on the surface. The results show that the corrosion rate of the alloy with cast defects is higher than that of the alloy without cast defects, but the defects do not change the composition of the resulting corrosion products. The defects increase the complexity of the alloy microstructure and the tendency toward galvanic corrosion, which reduce the corrosion potential from −3.83 to −86.31 mV and increase the corrosion current density from 0.228 to 0.23 μA⋅cm−2.

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