scholarly journals Effect of Molybdenum Content on the Corrosion and Microstructure of Low-Ni, Co-Free Maraging Steels

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 852
Author(s):  
Asiful H. Seikh ◽  
Hossam Halfa ◽  
Mahmoud S. Soliman
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Microstructural Analysis ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Alloying Element ◽  
X Ray ◽  
Maraging Steels ◽  
Eds Analysis ◽  
Electroslag Refining

Molybdenum (Mo) is an important alloying element in maraging steels. In this study, we altered the Mo concentration during the production of four cobalt-free maraging steels using an electroslag refining process. The microstructure of the four forged maraging steels was evaluated to examine phase contents by optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. Additionally, we assessed the corrosion resistance of the newly developed alloys in 3.5% NaCl solution and 1 M H2SO4 solution through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Furthermore, we performed SEM and energy-dispersive spectroscopy (EDS) analysis after corrosion to assess changes in microstructure and Raman spectroscopy to identify the presence of phases on the electrode surface. The microstructural analysis shows that the formation of retained austenite increases with increasing Mo concentrations. It is found from corrosion study that increasing Mo concentration up to 4.6% increased the corrosion resistance of the steel. However, further increase in Mo concentration reduces the corrosion resistance.

scholarly journals Enhancement of Acetone Gas-Sensing Responses of Tapered WO3 Nanorods through Sputtering Coating with a Thin SnO2 Coverage Layer

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 864 ◽  
Author(s):  
Yuan-Chang Liang ◽  
Yu Chao
Keyword(s):  
Gas Sensing ◽  
Microstructural Analysis ◽  
Xrd Analysis ◽  
Thin Layers ◽  
Elemental Distribution ◽  
Distribution Analysis ◽  
Acetone Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composite Nanorods

WO3–SnO2 composite nanorods were synthesized by combining hydrothermal growth of tapered tungsten trioxide (WO3) nanorods and sputter deposition of thin SnO2 layers. Crystalline SnO2 coverage layers with thicknesses in the range of 13–34 nm were sputter coated onto WO3 nanorods by controlling the sputtering duration of the SnO2. The X-ray diffraction (XRD) analysis results demonstrated that crystalline hexagonal WO3–tetragonal SnO2 composite nanorods were formed. The microstructural analysis revealed that the SnO2 coverage layers were in a polycrystalline feature. The elemental distribution analysis revealed that the SnO2 thin layers homogeneously covered the surfaces of the hexagonally structured WO3 nanorods. The WO3–SnO2 composite nanorods with the thinnest SnO2 coverage layer showed superior gas-sensing response to 100–1000 ppm acetone vapor compared to other composite nanorods investigated in this study. The substantially improved gas-sensing responses to acetone vapor of the hexagonally structured WO3 nanorods coated with the SnO2 coverage layers are discussed in relation to the thickness of SnO2 coverage layers and the core–shell configuration of the WO3–SnO2 composite nanorods.

scholarly journals Corrosion properties of Zn-Ni-P alloys in neutral model medium

2014 ◽  
Vol 12 (11) ◽  
pp. 1183-1193 ◽  
Author(s):  
Vassil Bachvarov ◽  
Miglena Peshova ◽  
Stefana Vitkova ◽  
Nikolai Boshkov
Keyword(s):  
Corrosion Resistance ◽  
Xrd Analysis ◽  
Ternary Alloys ◽  
X Ray Diffraction ◽  
Model Medium ◽  
Experimental Conditions ◽  
Corrosion Properties ◽  
X Ray ◽  
Protective Ability ◽  
Corrosion Medium

AbstractThe presented work reports on the peculiarities of the anodic behavior, corrosion resistance and protective ability of electrodeposited Zn-Ni-P alloys with a different composition in a model corrosion medium of 5% NaCl. Three characteristic coating types have been investigated using experimental methods such as potentiodynamic polarization (PD) technique and polarization resistance (Rp) measurements. In addition, X-ray diffraction (XRD) analysis as well as scanning electron microscopy (SEM) coupled with an Energy-dispersive X-ray (EDAX) device were applied to determine the differences in the chemical composition and surface morphology which appeared as a result of the corrosion treatment. The data obtained are compared to those of electrodeposited pure Zn coatings with identical experimental conditions demonstrating the enhanced protective characteristics of the ternary alloys during the test period in the model medium. The influence of the chemical and phase composition of the alloys on its corrosion resistance and protective ability is also commented and discussed.

Corrosion Behavior of Surfaced AM50 Magnesium Alloys under Stress Conditions

2010 ◽  
Vol 95 ◽  
pp. 79-83
Author(s):  
Amir Eliezer
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Spinel Phase ◽  
Ceramic Coatings ◽  
Open Circuit ◽  
Stress Conditions ◽  
X Ray Diffraction ◽  
X Ray

Micro-arc oxidization of AM50 magnesium alloys was studied. The influence of micro-arc oxidization process was investigated; phase structure were analyzed using X-ray diffraction (XRD). Open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion resistance of ceramic coatings formed on magnesium alloys under stress conditions. XRD analyses indicate that the ceramic coatings fabricated on the surface of magnesium alloys by micro-arc oxidization are composed of spinel phase MgAl2O4 The corrosion resistance of ceramic coatings is improved compared with magnesium alloy substrate.

Measurement of Alloying Degree of Galvannealed Steels by X-Ray Diffraction

2006 ◽  
Vol 321-323 ◽  
pp. 1461-1464 ◽  
Author(s):  
Hyoung Kuk Park ◽  
Jea Hwa Hong ◽  
Chong Soo Lee
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Quantitative Analysis ◽  
Xrd Analysis ◽  
Pls Regression ◽  
Processing Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Excellent Corrosion Resistance ◽  
Galvannealed Steel

Galvannealed steels are produced by reheating of Zinc-coated steels, in which the iron and the zinc are interdiffused to form Zn-Fe intermatallic compound. In recent years, application of galvannealed steel has increased due to its excellent corrosion resistance, good weldability and paintability. Galvannealed production requires strict control of processing conditions to obtain an optimal alloying degree in the coatings. The analysis of the alloying degree is very important since they are closely related to the corrosion and mechanical properties. This study is measurement of alloying degree of the galvannealed steel by using the XRD. Partial least squares (PLS) model is a powerful multivariate tool that has been successfully applied to the quantitative analysis of data in XRD. The alloying degree was determined by using PLS regression to a concentration accuracy of 0.2%. The XRD analysis and proposed PLS model can be successfully used to determine the alloying degree of industrially produced galvannealed steel.

The Fabrication of Refractory Cordierite from Aluminium Buff Mixture

2016 ◽  
Vol 690 ◽  
pp. 97-102
Author(s):  
Nuntaporn Kongkajun ◽  
Parinya Chakartnarodom ◽  
Warunee Borwornkiatkaew
Keyword(s):  
Microstructural Analysis ◽  
Secondary Phase ◽  
Xrd Analysis ◽  
Batch Composition ◽  
Brazilian Test ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Properties Of Materials

The aim of this work is to propose the utilization of aluminium buff from aluminium part manufacturer as a raw material for cordierite batch composition. The powder mixtures were compacted by uniaxial pressing. The green compacts were sintered at temperature in the range 1300-1400°C for 2 hours in air. The physical properties were characterized by Archimedes method, Brazilian test and dilatometry. Phase and microstructural analysis were done by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis showed the major phase was cordierite along with sapphirine as a secondary phase. The fired properties of materials were demonstrated that the optimal properties was achieved from the specimen sintered at 1375 °C.

scholarly journals Microstructural Evolutions and its Impact on the Corrosion Behaviour of Explosively Welded Al/Cu Bimetal

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 634
Author(s):  
Mohammad Reza Jandaghi ◽  
Abdollah Saboori ◽  
Gholamreza Khalaj ◽  
Mohammadreza Khanzadeh Ghareh Shiran
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Welding Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminium Copper ◽  
Melting Pool ◽  
Intermetallic Layers

In this study, the microstructural evolutions and corrosion resistance of aluminium/copper joint fabricated through explosive welding process have been thoroughly investigated, while stand-off distance was variable. Microstructural analyses demonstrate that, regardless of grain refinement in the welding boundary, increasing the stand-off space is followed by a higher thickness of the localized melting pool. X-Ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) analyses recognized the binary intermetallic layers as a combination of Al2Cu and AlCu. Polarization and electrochemical impedance spectroscopy (EIS) corrosion tests revealed that a higher stand-off distance resulted in the increment of corrosion potential, current rate, and concentration gradient at the interface owing to the remarkable kinetic energy of the collision, which impaired corrosion resistance.

scholarly journals Enhanced Corrosion Resistance of SiCp/ 2009 Al by Cerium and Lanthanum Conversion Treatment

2018 ◽  
Vol 778 ◽  
pp. 251-255
Author(s):  
Irfan Aziz ◽  
Qi Zhang
Keyword(s):  
Corrosion Resistance ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Localized Corrosion ◽  
Al Alloy ◽  
Unreinforced Alloy ◽  
Maximum Increase ◽  
X Ray ◽  
Eds Analysis ◽  
Polarization Studies

The present study investigates the effect of lanthanide chlorides conversion coatings on the corrosion response of the 2009 Al alloy and SiCp reinforced 2009 Al MMCs. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies showed that the localized corrosion resistance increased after treatments with solutions having various combinations of CeCl3.7H2O and LaCl3.7H2O, with maximum increase noticed for 5000ppm CeCl3.7H2O. It was found that the protection degree effect obtained under similar coating conditions for 25 vol.% SiCp/2009 Al was relatively higher than 15vol.% SiCp/ 2009 Al MMC, but both of them were less than that of the unreinforced alloy. Scanning electron microscopy (SEM) accompanied with energy dispersive spectroscopy (EDS) analysis revealed the deposition of Ce and/ or La oxides/ hydroxides on cathodic intermetallics/ SiCp and the existence of crevices at the SiCp/ matrix interfaces. X-ray photoelectron spectroscopy (XPS) results indicated that Ce was incorporated as Ce3+ and Ce4+ species in the coatings.

Influence of Plasticizers on the Electrical Conductivity of Polyacrylonitrile (PAN)/Lithium-Montmorillonite (Li-MMT) Polymer Composite Electrolyte

2017 ◽  
Vol 894 ◽  
pp. 89-93
Author(s):  
Mitch Irene Kate N. Galvan ◽  
Leslie Joy L. Diaz
Keyword(s):  
Electrical Conductivity ◽  
Polymer Composite ◽  
Electrochemical Impedance ◽  
Current Trend ◽  
Xrd Analysis ◽  
Dimethyl Formamide ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Composite Electrolyte ◽  
X Ray

With the current trend of miniaturization and portability of electronic gadgets, the development of polymer composite electrolyte (PCE) gained much research interest. In this study PAN matrix was plasticized with various dimethyl formamide (DMF)/ propylene carbonate (PC) ratios. X-ray diffraction (XRD) analysis revealed that both DMF and PC reduce the crystallinity of PAN. Yet, films with higher amount of PC caused much decrease in crystallinity, which is indicated by lowering of full with at half maximum (FWHM) at the utmost 57% when the DMF/PC ratio is 1:2. Differential scanning calorimetry (DSC) analysis also revealed that glass transition temperature (Tg) of PAN decreased from 83.34°C to 50.27°C when plasticized with pure DMF and to temperature lower than ambient condition when PC alone was used. Upon incorporation of 15 wt% Li-MMT, PCEs with pure DMF exhibited the highest electrical conductivity, which is 3.6x10-8 S/cm based on electrochemical impedance spectroscopy (EIS). This suggests that the electrical conductivity is not dictated by the decrease on polymer host crystallinity alone. The type of plasticizer and appropriate combination was shown to have an effect wherein the plasticizer that causes higher degree of solvation and has lower boiling point is thought to provide more hopping sites for electrons due to higher amount of broken bonds in the nitrile group of PAN.

Structure and Corrosion Resistance of Zn-Ni and Zn-Ni-W Coatings

2010 ◽  
Vol 636-637 ◽  
pp. 1042-1046
Author(s):  
Magdalena Popczyk ◽  
Antoni Budniok
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Zinc Bath ◽  
Corrosion Resistant ◽  
X Ray ◽  
Electrochemical Corrosion Resistance ◽  
Galvanostatic Conditions

Zn-Ni and Zn-Ni-W coatings were prepared by the electrodeposition under the galvanostatic conditions (jdep. = -0.020 A cm-2) from the zinc bath containing additionally ions of nickel (Zn-Ni) and ions of nickel and tungsten (Zn-Ni-W). The Zn-Ni coating after electrodeposition was subjected to outside passivation and in the Zn-Ni-W coating the passive function performs tungsten (inside passivation). The surface morphology of the coatings was studied using a scanning electron microscope (JEOL JSM - 6480). Chemical composition of obtained coatings was determined by the X-ray fluorescence spectroscopy (XRF). Phase composition investigations were conducted by X-ray diffraction method using a Philips diffractometer. Electrochemical corrosion resistance investigations were carried out in the 3% NaCl, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found that Zn-Ni coating is more corrosion resistant than the Zn-Ni-W coating.

The influence of hexamethylenetetramine on the structure and corrosion resistance of phosphate coating on AZ31 magnesium alloy

2016 ◽  
Vol 63 (3) ◽  
pp. 161-165 ◽  
Author(s):  
Jiansan Li ◽  
Yali Li ◽  
Yanqin Chen ◽  
Jiawei Sun ◽  
Chunxiao Wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
Design Methodology ◽  
Energy Dispersive Spectrometry ◽  
Electrochemical Impedance ◽  
Phosphate Coating ◽  
X Ray Diffraction ◽  
Content Type ◽  
X Ray ◽  
Phosphate Coatings

Purpose This paper aims to report the influence of hexamethylenetetramine (HMTA) on phosphate coatings formed on AZ31 magnesium alloys. Design/methodology/approach These phosphate coatings were obtained by immersing magnesium alloys in phosphate baths with HMTA. The morphology and composition of the phosphate coatings were investigated via scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. Findings The phosphate coatings were mainly composed of CaHPO4·2H2O. The HMTA concentration in the phosphate bath influenced the crystallization and corrosion resistance of the phosphate coating. Originality/value The polarization curve shows that the anti-corrosion qualities of the phosphate coating were optimal when the HMTA concentration was 1.0 g/L in the phosphate bath. Electrochemical impedance spectroscopy (EIS) shows that the electrochemical impedances increased gradually when the HMTA concentration varied from 1.0 to 3.0 g/L.

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