scholarly journals Investigation of Zirconium Effect on the Corrosion Resistance of Aluminum Alloy Using Electrochemical Methods and Numerical Simulation in an Acidified Synthetic Sea Salt Solution

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1982 ◽  
Author(s):  
Yong-Sang Kim ◽  
Jong Park ◽  
Byeong-Seon An ◽  
Young Lee ◽  
Cheol-Woong Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Galvanic Corrosion ◽  
Sea Salt ◽  
Al Alloy ◽  
Alloying Element ◽  
Intermetallic Particles ◽  
Transmission Electron ◽  
Corrosion Simulation

Corrosion resistance of Zr that has been added to an Al alloy (U1070) is higher than that of a commercial Al alloy (A1070). A decreasing number and size of Al3Fe intermetallic particles (IMPs) were observed by electron microprobe analysis and transmission electron microscopy. Based on the numerical corrosion simulation, it was confirmed that decreasing the number and size of IMPs was favorable for improving the corrosion resistance of the Al alloy due to the reduction of the galvanic effect. In addition, Al3Zr was found to be insignificant in promoting galvanic corrosion within the Al matrix. Thus, Zr is an advantageous alloying element for improving the corrosion resistance of the Al alloy.

Characterization of metallurgical grade silicon

1990 ◽  
Vol 5 (9) ◽  
pp. 1894-1899 ◽  
Author(s):  
J. C. Anglézio ◽  
C. Servant ◽  
F. Dubrous
Keyword(s):  
Electron Microscopy ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Optical Metallography ◽  
Metallurgical Grade Silicon ◽  
Transmission Electron ◽  
Grade Silicon ◽  
Precipitated Phases ◽  
Scanning Electron

Optical metallography, scanning electron microscopy, electron microprobe analysis, and transmission electron microscopy were used to characterize metallurgical grade silicon, produced in an electric are furnace. Coincidence fraction determinations were assumed to be Σ7 and Σ9 when grain boundaries are underlined by precipitated phases and Σ3 when they are not. The study of intergranular compounds was emphasized; ten compounds were found, the main ones being Si2Ca, Si8Al6Fe4Ca, Si2Al2Ca, Si2FeTi, and Si2.4Fe (α leboitc). The precipitation of these compounds was discussed according to the principal impurity concentrations in silicon. The crystalline structure of Si8Al6Fe4Ca was determined to be triclinic with a = 1.3923 nm, b = 1.3896 nm, c = 1.3900 nm and α = 92.4°, β = 110.3°, γ = 119.9°.

scholarly journals Improvement of Pitting-Corrosion Resistance of Ultrafine-Grained 7475 Al Alloy by Aging

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 360
Author(s):  
Ewa Ura-Bińczyk
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Al Alloy ◽  
Subsequent Aging ◽  
Fine Grained ◽  
Transmission Electron ◽  
Pitting Corrosion Resistance ◽  
Ultrafine Grained ◽  
Ultrafine Grained Microstructure

The effect of aging on the resistance to pitting corrosion of ultrafine-grained 7475 aluminium (Al) alloy processed by hydrostatic extrusion (HE) is studied. Differences in the microstructure were investigated using secondary electron (SEM) and transmission electron microscopy (TEM). Corrosion tests were performed in 0.1 M NaCl, and characterization of corroded surface was performed. The results of this work show that the pitting susceptibility of ultra-fine grained 7475Al is related to the distribution of MgZn2 precipitates. After HE, the formation of An ultrafine-grained microstructure at the grain boundaries of ultrafine grains is observed, while subsequent aging results in the formation of MgZn2 precipitates in the grain interior. Grain refinement increases susceptibility to localized attack, while the subsequent aging improves the overall corrosion resistance and limits the propagation of corrosion attack.

Magnetite exsolution in almandine garnet

1986 ◽  
Vol 50 (358) ◽  
pp. 621-633 ◽  
Author(s):  
A. J. Brearley ◽  
P. E. Champness
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Spinel Phase ◽  
Analytical Electron Microscopy ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Rare Situation

AbstractThree almandine-rich metamorphic garnets have been studied by analytical electron microscopy and electron microprobe analysis. Electron microprobe analyses with total Fe calculated as Fe2+ show that there are no significant departures from stoichiometry due to the presence of Fe3+ in any of the garnets studied. However, in the transmission electron microscope (TEM) all the garnets were found to contain myriad spherical, iron-rich particles up to 400 Å in diameter. Microdiffraction techniques have revealed that the particles are a cubic spinel phase, consistent with magnetite. There is no crystallographic relationship between the host garnet and the particles, a rare situation for exsolution processes. The presence of such particles is interpreted in terms of the exsolution of magnetite from almandine garnet during cooling. This can apparently occur at temperatures below 55°C. The size of the particles is a qualitative indicator of the cooling rate of the rock, but is also dependent on the original Fe3+ content of the host garnet.

A study of iron-bearing rutiles in the paragenesis TiO2-Al2O3-P2O5-SiO2

1978 ◽  
Vol 42 (322) ◽  
pp. 255-263 ◽  
Author(s):  
A. Putnis ◽  
M. M. Wilson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Stable Equilibrium ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Temperature Transformation ◽  
Kinetics Of ◽  
Iron Bearing

SummaryHydrothermal ruffles from a suite of rocks at Mount Perry, Queensland, have been studied in thin section, by electron microprobe analysis, and by transmission electron microscopy. The iron-bearing rutiles, while originally singte-phase, are found to exsolve a sequence of iron-rich precipitates on experimental annealing, with hematite being formed as the stable equilibrium precipitate. Experiments at different temperatures and annealing times enable a time-temperature-transformation plot to be drawn for the exsolution process. The kinetics of this process are used to conclude that the rutiles formed below about 450 °C.

Influence of Acrylamide on Corrosion-Resistance and Strength of Cement Pastes

2011 ◽  
Vol 261-263 ◽  
pp. 318-322
Author(s):  
Zhen Liu ◽  
Qi Wang ◽  
Peng Song ◽  
Lu Fei Tian
Keyword(s):  
Corrosion Resistance ◽  
Ordinary Portland Cement ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Mercury Porosimetry ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
X Ray

Test specimens were made from ordinary Portland cement (OPC) pastes containing different percentages of Acrylamide. It was measured the strength with time change. The effect of different percentages of Acrylamide on the sulfate resistance and inner pore distribution of lightweight aggregate concrete was investigated.. Test specimens were studied by X-ray diffraction, electron microprobe analysis and mercury porosimetry. The results show: The best percentage of Acrylamide was about 4%, which leads to the higher compression strength. when the content of Acrylamide was 4%, the Sulfate-Corrosion Resistance reached the climax.

scholarly journals An electron microscopic histochemical and analytical X-ray microprobe study of calcification in Bruch's membrane from human eyes.

1981 ◽  
Vol 29 (5) ◽  
pp. 601-608 ◽  
Author(s):  
W L Davis ◽  
R G Jones ◽  
H K Hagler
Keyword(s):  
Electron Microscopy ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Phosphotungstic Acid ◽  
Electron Microscopic ◽  
X Ray ◽  
Transmission Electron ◽  
Dense Deposits ◽  
Calcium And Phosphorus ◽  
Human Eyes

Transmission electron microscopy, electron microprobe analysis, high temperature microincineration, and electron microscopic histochemical procedures were used to study the electron-dense deposits characteristic of the macular aspect of aged human eyes. These inorganic deposits were rich in calcium and phosphorus and selectively removed by flotation on formic acid. The amorphous decalcified masses showed a significant sulfur peak and were readily stained with acidic phosphotungstic acid. The latter observations are indicative of the presence of organic matrical proteoglycan. Such data may be a further indication that proteoglycans are retained at sites of calcification.

Hardness and Corrosion Behavior of Aged 6063 Al Alloy

2014 ◽  
Vol 1046 ◽  
pp. 54-57 ◽  
Author(s):  
Chun Lin He ◽  
Xiao Dan Meng ◽  
Guo Feng Ma ◽  
Jian Ming Wang ◽  
Zhao Fu Du ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Intergranular Corrosion ◽  
Corrosion Test ◽  
Artificial Aging ◽  
Galvanic Corrosion ◽  
Peak Hardness ◽  
Al Alloy ◽  
Accelerated Corrosion ◽  
6063 Al Alloy ◽  
Accelerated Corrosion Test

The effect of artificial aging on the corrosion properties of 6063 Al alloy was investigated by optical microscope, field emission scanning electron microscope (FE-SEM) and accelerated corrosion test. Accelerated corrosion test revealed that the corrosion resistance of the alloy strongly depended on artificial aging times, and the corrosion weight gain curve of the aged alloy was greatly in agreement with that of hardness vs. aging times, showing that the lowest corrosion resistance was exhibited at peak aged condition. It is found that pitting is the main corrosion form for the 6063 aluminum alloy aged with different times at 210°C, and slight intergranular corrosion is also found at peak hardness. It is believed that pitting results from galvanic corrosion between Al9Fe2Si2 particles and matrix Al while intergranular corrosion results from galvanic corrosion between Mg2Si and matrix Al.

Evaluation on the Mechanical and Corrosion Resistance of ALDC 12 Al Alloy by Three Types of Heat Treatments

2017 ◽  
Vol 744 ◽  
pp. 249-253
Author(s):  
Kyung Man Moon ◽  
Sung Yul Lee ◽  
Jae Hyun Jeong ◽  
Myeong Hoon Lee
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Artificial Aging ◽  
Galvanic Corrosion ◽  
Natural Aging ◽  
Heat Treatments ◽  
Al Alloys ◽  
Hot Water ◽  
Al Alloy ◽  
Artificial Heat

Al is a active metal. However, it has a generally fine oxide film with thin and protective barrier, which is stable in air and neutral aqueous solution. Thus, Al alloys have been widely used in architectural trim, cold & hot-water storage vessels and piping. However, Al and most of their alloys may be easy to be corroded with various patterns of corrosion such as pitting, intergranular and galvanic corrosion etc. in the case of exposure to various industrial and marine corrosive environments. Therefore, an optimum evaluation of corrosion resistance for Al and Al alloys may be more important in a economical point of view. In this study, characteristics evaluation for ALDC 12 Al alloy by solution, normalizing, and aging (natural and artificial) heat treatments was carried out using electrochemical methods etc.. We can see that the hardness of ALDC 12 Al alloy were decreased by solution and aging heat treatments, in particular, the solution and natural aging (SNA) heat treatments indicated the lowest value of hardness. However, the lower hardness by heat treatment, the better corrosion resistance, for instance, the solution and natural aging (SNA) heat treatment exhibited the best corrosion resistance with showing the lowest hardness. Furthermore, the highest hardness was observed after normalizing and artificial aging (NAA) heat treatments. Therefore, it is considered that if improvement of the hardness as well as the corrosion resistance were to be required together, the normalizing and artificial aging (NAA) heat treatment should be performed. On the other hand, the solution and natural aging (SNA) heat treatment is thought to be an optimum heat treatment method for only corrosion resistance improvement.

Investigation of Natural and Artificial Zr-silicate Gels

2006 ◽  
Vol 932 ◽  
Author(s):  
Boris E. Burakov ◽  
Andrey Ph. Smetannikov ◽  
Evgeniy B. Anderson ◽  
Alexander Yu. Alexeev
Keyword(s):  
Electron Microscopy ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Chemical Durability ◽  
High Chemical ◽  
X Ray ◽  
Transmission Electron ◽  
Oxide Phases ◽  
Intermediate Storage

ABSTRACTSample of natural Zr-silicate gel containing up to 13 wt.% U was characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and electron microprobe analysis (EPMA) method. It was found that gel matrix is amorphous in general; however, it contains non-identified nanocrystallites. No separated oxide phases of U, Zr or Si were observed in a gel matrix. After sintering in air at 1400°C for 1 hour gel transformed largely into crystalline zircon, (Zr,U)SiO4. Uranium was not found in any other phases besides zircon. It was assumed that high chemical durability of natural Zr-P-U-Ti-silicate gel is caused by two competing processes which exist under self-irradiation conditions: 1) crystallization of the gel and 2) metamictization of the crystallized zircon and other phases.Synthetic samples of Zr-silicate gel doped with Ce, U, Pu and Am were obtained and studied in comparison with natural samples. It was suggested to use artificial solid Zr-silicate gels for durable fixation of actinides for the goal of long-term or intermediate storage.

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