Micro Experimental Research on Cement Stone under Sulfate Erosion

2012 ◽  
Vol 588-589 ◽  
pp. 95-103
Author(s):  
Jue Zhu ◽  
Qian Chen ◽  
Yuan Yuan Ding
Keyword(s):  
Immersion Time ◽  
Sulfate Solution ◽  
Cement Stone ◽  
Erosion Product ◽  
Sulfate Ion ◽  
Cement Ratio ◽  
X Ray ◽  
Ion Concentrations ◽  
Scanning Electron ◽  
Xrd Method

In this article, micro investigation of the cement stone under sulfate erosion is carried out by using SEM (Scanning Electron Microscope). The XRD method is also employed to semi-quantitatively analyze the erosion product. The cement stones whose water-cement is 0.45, 0.55, 0.65, respectively, immersed in sulfate solution whose sulfate ion concentrations is 0%, 3%, 4%, 5%, 6%. After different immersion time of 24 days, 45 days and 60 days, the microstructure of samples is detect by the SEM. The energy-dispersive X-ray analysis (EDX) is taken to determine the general elements in samples. The XRD method is employed to semi-quantitatively determine the weight percents of ettringite and gypsum in cement stone samples. Through comparative analysis, it tries to point out how the sulfate ion and water-cement ratio will affect the erosion products.

Deterioration of concrete containing limestone powder exposed to sulfate attack at ambient temperature

2021 ◽  
Vol 11 (5) ◽  
pp. 724-731
Author(s):  
Hemin Liu ◽  
Qian Huang ◽  
Liang Zhao
Keyword(s):  
Ambient Temperature ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
Adverse Influence ◽  
Powder Content ◽  
Scanning Electron

This study investigates the deterioration of concrete containing limestone powder exposed to sulfate solution under ambient temperature (20~25 °C). Microstructure and mineral phases within the attacked concrete were measured by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). It was found that the addition of limestone powder increased the initial porosity of concrete. Consequently, a larger amount of SO2–4 ions diffused into the concrete containing limestone powder, and their degree of deterioration caused by sulfate attack increased with the increase in limestone powder content. At ambient temperature, gypsum and ettringite were the major attack products, respectively within the surface and nearsurface portions of concrete containing limestone powder, which was consistent with the products of sulfate attack within concrete without limestone powder. Therefore, the type and distribution of the attack products in concrete had not been revised due to the addition of limestone powder. Nevertheless, the adverse influence of limestone powder on the sulfate resistance of concrete, even at ambient temperature, should be considered. Furthermore, effective measures should be implemented to improve the durability of concrete containing limestone powder in this environment.

Zinc Oxide Nanorods Characteristics Prepared by Sol-Gel Immersion Method Immersed at Different Times

2013 ◽  
Vol 667 ◽  
pp. 375-379 ◽  
Author(s):  
M. Awalludin ◽  
Mohamad Hafiz Mamat ◽  
Mohd Zainizan Sahdan ◽  
Z. Mohamad ◽  
Mohamad Rusop
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Immersion Time ◽  
Sol Gel ◽  
Zno Nanorods ◽  
Zinc Oxide Nanorods ◽  
Immersion Method ◽  
X Ray ◽  
Oxide Nanorods ◽  
Scanning Electron

This paper focus on zinc oxide (ZnO) nanorods prepared using sol-gel immersion method immersed at different time. Immersion times have been varied 1~24 hr and the characteristics of each sample have been observed. The effects of immersion time on ZnO nanorods thin films have been studied in surface morphology and structural properties using Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD), respectively.

Influence of NaCl on Mechanical Properties and Microstructure of Cement Stone

2013 ◽  
Vol 700 ◽  
pp. 136-139
Author(s):  
Xin Tang ◽  
Jin Huang
Keyword(s):  
Mechanical Properties ◽  
Sodium Chloride ◽  
Crystalline Phase ◽  
The Other ◽  
Cement Stone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Crystalline Phase ◽  
Gel Phase ◽  
Scanning Electron

The mechanical properties and microstructure of cement stone containing different sodium chloride (NaCl) have been investigated. Uni-axial compression experiments were used to study mechanical properties. The main crystalline phase composition of cement specimens was determined by means of X-ray diffraction (XRD). Surface morphology of cement stone was observed by using scanning electron microscopy (SEM). The obtained results showed that compared with the other samples, the sample incorporated 14% sodium chloride was quite different, whose compressive strength was higher and microstructure was denser. The sodium chloride crystalline phase and the hydration (C-S-H) gel phase co-existed.

Experimental Research on High-Strength Super Sulphate Cement Paste Mixed with Superfine Mineral Admixtures

2014 ◽  
Vol 629-630 ◽  
pp. 150-155
Author(s):  
Jun Wang ◽  
Bao Ying Yu ◽  
Long Yang ◽  
Yu Xin Gao ◽  
Jia Yu Xiang
Keyword(s):  
Silica Fume ◽  
High Strength ◽  
Hydration Product ◽  
Mineral Admixtures ◽  
Hydration Reaction ◽  
X Ray Diffraction ◽  
Cement Ratio ◽  
X Ray ◽  
Early Strength ◽  
Scanning Electron

Aimed at the performance affect of high-strength super sulphate cement (SSC) paste mixed with superfine mineral admixtures, influence of microbead and silica fume replacing SSC quantity on high-strength SSC paste compression strength were studied under water-cement ratio 0.18; Hydration product morphology and phase were further compared by scanning electron microscopy and X-ray diffraction analyzer in this paper. Results show that, compared with sample HS-1, 3-day strength of HS-2 and HS-3 were increased by 5% and 10%, 28d strength basically unchanged; Furthermore, early strength of HS-7 sample slightly higher and late strength basically unchanged. SSC by adding 5% microbead and 3% silica fume (HS-11) has compressive strength 50.8MPa at 3 days and 86.1MPa at 28 days is significantly higher than other samples. Early strength of HS-11sample mainly depends on hydration reaction of SSC and particle filling effect of admixtures, later strength is due to accelerating consumption of gypsum and promoting formation of ettringite.

scholarly journals Electrodeposition of Cu-Mn Films as Precursor Alloys for the Synthesis of Nanoporous Cu

Electrochem ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 520-533
Author(s):  
Ezer Castillo ◽  
Nikolay Dimitrov
Keyword(s):  
Metal Ion ◽  
Reduction Potential ◽  
Type I ◽  
X Ray ◽  
Ion Concentrations ◽  
Galvanostatic Deposition ◽  
Anodic Stripping ◽  
Voltammetric Studies ◽  
Current Densities ◽  
Scanning Electron

Cu-Mn alloy films are electrodeposited on Au substrates as precursor alloys for the synthesis of fine-structured nanoporous Cu structures. The alloys are deposited galvanostatically in a solution containing ammonium sulfate, (NH4)2SO4, which serves as a source of the ammine ligand that complexes with Cu, thereby decreasing the inherent standard reduction potential difference between Cu and Mn. The formation of the [Cu(NH3)n]2+ complex was confirmed by UV-Vis spectroscopic and voltammetric studies. Galvanostatic deposition at current densities ranging from 100 to 200 mA⋅cm−2 generally resulted in the formation of type I, crystalline coatings as revealed by scanning electron microscopy. Although the deposition current efficiency is (<30%) generally low, the atomic composition (determined by energy dispersive X-ray spectroscopy) of the deposited alloys range from 70–85 at% Mn, which is controlled by simply adjusting the ratio of the metal ion concentrations in the deposition bath. Anodic stripping characterization revealed a three-stage dissolution of the deposited alloys, which suggests control over the selective removal of Mn. The composition of the alloys obtained in the studies are ideal for electrochemical dealloying to form nanoporous Cu.

scholarly journals Effects of Immersion Time and 5-Phenyl-1H-tetrazole on the Corrosion and Corrosion Mitigation of Cobalt Free Maraging Steel in 0.5 M Sulfuric Acid Pickling Solutions

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
El-Sayed M. Sherif ◽  
Asiful H. Seikh
Keyword(s):  
Maraging Steel ◽  
Electron Spectroscopy ◽  
Polarization Resistance ◽  
Immersion Time ◽  
Electrochemical Impedance ◽  
Steel Corrosion ◽  
Polarization Data ◽  
Exposure Test ◽  
X Ray ◽  
Scanning Electron

The effect of exposure time and 5-phenyl-1H-tetrazole on the corrosion and corrosion mitigation of cobalt free maraging steel in 0.5 M H2SO4pickling solutions has been reported using electrochemical and spectroscopic investigations. Potentiodynamic polarization data showed that the increase of immersion time from 0 min to 120 min increases the corrosion rate and decreases the polarization resistance of the maraging steel. On the other hand, the addition of PHTA and the increase of its concentration decrease all the corrosion parameters of the steel at all exposure test periods. Electrochemical impedance spectroscopy measurements agreed with the obtained polarization data. Scanning electron spectroscopy and energy dispersive X-ray investigations confirmed that the inhibition of the steel corrosion is achieved via the adsorption of the PHTA molecules onto the steel precluding its surface from being dissolved.

X-Ray Phase Analysis of High-Aluminate Cements under Conditions of early Compression

2018 ◽  
Vol 284 ◽  
pp. 1107-1113
Author(s):  
Yu.Yu. Galkin ◽  
S.A. Udodov
Keyword(s):  
Phase Analysis ◽  
High Alumina ◽  
Cement Stone ◽  
Early Age ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
X Ray ◽  
Physical Impact ◽  
The Moment ◽  
Ray Patterns

Study of the structure of cementitious composites under conditions of early-age compression is essential for development of measures to improve their response to mechanical and physical impact at the earliest stage of hardening. The article considers the influence of early-age compression on the structure of high-aluminate cement which has been studied using X-ray phase analysis. Concrete mixes with different water-cement ratio have been designated as targets for research. It has been established that the age of the cement to the moment of load application impacts on composition of formed hydrates, as well as on amorphousness of the structure of high-alumina cement stone. Compression at a very early age leads to an increase in the number of peaks related to hexagonal hydroaluminates and aluminum hydroxide. Load impact results in various recrystallization behaviors. Transformation of hexagonal hydroaluminates into cubical ones is proceeding faster with growth of water-cement ratio in the samples under compression. This is illustrated by an increase of a number of related peaks in X-ray patterns. Notation: C=CaO; A=Al2O3; H=H2O; S=SiO2; M=MgO.

Fabrication of Zn-Ni-Mn alloy by electrodeposition and its characterization

2018 ◽  
Vol 36 (6) ◽  
pp. 547-558 ◽  
Author(s):  
Fawzi H. Assaf ◽  
Mortaga M. Abou-Krisha ◽  
Walid M. Daoush ◽  
Ahmed A. Eissa
Keyword(s):  
Platinum Electrode ◽  
Sulfate Solution ◽  
X Ray Diffraction ◽  
High Corrosion Resistance ◽  
Surface Appearance ◽  
X Ray ◽  
Manganese Alloys ◽  
Ni Alloy ◽  
Aqueous Sulfate Solution ◽  
Scanning Electron

AbstractElectrodeposition and stripping of Zn, Mn and Ni metals and their alloys were investigated in an aqueous sulfate solution. The effect of coating processes and its impact on the substrate were evaluated by investigating the prepared alloys with X-ray diffraction analysis, scanning electron microscopy and atomic absorption spectroscopy. The electrodeposition mechanism of the Zn-Ni-Mn alloy was found to be an anomalous type. The high corrosion resistance of the Zn-Ni-Mn alloy, as well as its preferable surface appearance, has been ascertained compared with the electrodeposited Zn-Ni alloy under homogeneous conditions. It was found that Mn can be codeposited with Ni or with Ni and Zn understudied conditions where it does not deposit in its pure form. During electrodeposition of manganese alone or manganese alloys, a dark brown deposit was formed on the counter platinum electrode surface as a result of oxidation to manganese dioxide.

scholarly journals Beneficial Effects of Vanadium Additions on the Corrosion of Ti6AlxV Alloys in Chloride Solutions

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 264 ◽  
Author(s):  
El-Sayed M. Sherif ◽  
Hany S. Abdo ◽  
Nabeel H. Alharthi
Keyword(s):  
Electron Microscopy ◽  
Immersion Time ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Test Medium ◽  
X Ray ◽  
Beneficial Effects ◽  
Cyclic Potentiodynamic Polarization ◽  
Scanning Electron

The beneficial effects of V addition on the corrosion of a newly manufactured Ti6AlxV (x = 2 wt %, 4 wt %, 6 wt %, and 8 wt %) alloys after various exposure periods in 3.5% NaCl solutions were reported. The Ti6AlxV were produced from their raw powders using mechanical alloying. Several electrochemical techniques such as electrochemical impedance spectroscopy, cyclic potentiodynamic polarization, and potentiodynamic current versus time at 300 mV experiments were conducted. The surface morphology and the elemental analysis were performed using scanning electron microscopy and energy dispersive X-ray analyses. All results were consistent with each other revealing that the increase of V content increases the resistance of the alloys against corrosion. The increase of corrosion resistance was achieved by the role of V in decreasing the rate of corrosion as a result of the formation of oxide films on the surface of the alloys. This effect was found to increase with prolonging the immersion time of the Ti6AlxV alloys in the test medium from 1 h to 24 h and further to 48 h.

Influence of Compound Bonding Agent on the Performance and the Microstructure of Proppant

2013 ◽  
Vol 575-576 ◽  
pp. 519-522
Author(s):  
Jie Jing Sun ◽  
Lu Lu Qin ◽  
Xue Hua Song
Keyword(s):  
Sintering Temperature ◽  
Raw Materials ◽  
Sintered Sample ◽  
Bonding Agent ◽  
National Standard ◽  
X Ray Diffraction ◽  
Binding Agent ◽  
X Ray ◽  
Scanning Electron ◽  
Xrd Method

Low-density proppants have been developed using two kinds of bauxites containing different ratios of aluminum as main raw materials and compound liquid as a binding agent. The influences of the amount of compound bonding agent and the sintering temperature on the performance of the proppant were studied. The phase composition of calcined sample was identified by X-ray diffraction (XRD) method. The microstructure of the sintered sample was characterized by scanning electron microscope (SEM). It is shown that the proppant prepared with increasing compound bonding agent can meet the national standard. With the increase of the sintering temperature, mullite with uniform grain size is formed.

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