ENHANCEMENT OF EXFOLIATION CORROSION RESISTANCE OF ALUMINIUM ALLOY 5083 BY SHOT PEENING

2018 ◽  
Vol 25 (07) ◽  
pp. 1950020
Author(s):  
A. VINOTH JEBARAJ ◽  
L. AJAYKUMAR ◽  
C. R. DEEPAK ◽  
K. V. V. ADITYA
Keyword(s):  
Corrosion Resistance ◽  
Aluminium Alloy ◽  
Shot Peening ◽  
Roughness Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Exfoliation Corrosion ◽  
Marine Applications ◽  
Textural Changes ◽  
Chloride Environment

The present work is an effort to study the influence of shot peening on the exfoliation corrosion behavior of aluminium alloy (AA) 5083. Surface textural changes induced by shot peening was characterized using microstructural and X-ray diffraction analysis. The surface roughness parameters were measured to study the benefits of peening induced surface topography. Further, the hardness survey was carried out to assess the severe plastic deformation on the peened layers. As a result, excellent resistance against exfoliation corrosion was achieved in the chloride environment. Shot peening plays major role in enhancing the corrosion resistance of AA 5083. In the absence of exfoliation attack, the unpeened sample surfaces such as ground, milled, and as received conditions end up with a significant pitting attack. The findings of this work will be useful for the aluminium alloy fabrications involved in the marine applications.

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.

Influence of Fly Ash on Corrosion Resistance of Refractory Forsterite-Spinel Ceramics

2021 ◽  
Vol 325 ◽  
pp. 181-187
Author(s):  
Martin Nguyen ◽  
Radomír Sokolář
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Resistance ◽  
Fly Ash ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Zones ◽  
Refractory Ceramics ◽  
Scanning Electron

This article examines the influence of fly ash on corrosion resistance of refractory forsterite-spinel ceramics by molten iron as a corrosive medium. Fly ash in comparison with alumina were used as raw materials and sources of aluminium oxide for synthesis of forsterite-spinel refractory ceramics. Raw materials were milled, mixed in different ratios into two sets of mixtures and sintered at 1550°C for 2 hours. Samples were characterized by X-ray diffraction analysis and thermal dilatometric analysis. Crucibles were then made from the fired ceramic mixtures and fired together with iron at its melting point of 1535°C for 5 hours. The corrosion resistance was evaluated by scanning electron microscopy on the transition zones between iron and ceramics. Mixtures with increased amount of spinel had higher corrosion resistance and mixtures with fly ash were comparable to mixtures with alumina in terms of corrosion resistance and refractory properties.

A Kinematic Hardening Finite Elements Model to Evaluate Residual Stresses in Shot-Peened Parts, Local Measurements by X-Ray Diffraction

2006 ◽  
Vol 524-525 ◽  
pp. 161-166 ◽  
Author(s):  
Choumad Ould ◽  
Emmanuelle Rouhaud ◽  
Manuel François ◽  
Jean Louis Chaboche
Keyword(s):  
Finite Elements ◽  
Residual Stresses ◽  
Shot Peening ◽  
Kinematic Hardening ◽  
Constitutive Law ◽  
Loading Path ◽  
Isotropic Hardening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Local Measurements

Experimental analysis can be very costly and time consuming when searching for the optimal process parameters of a new shot-peening configuration (new material, new geometry of the part…). The prediction of compressive residual stresses in shot-peened parts has been an active field of research for the past fifteen years and several finite elements models have been proposed. These models, although they give interesting qualitative results, over-estimate, most of the time, the level of the maximal compressive stresses. A better comprehension of the phenomena and of the influence of the parameters used in the model can only carry a notable improvement to the prediction of the stresses. The fact that the loading path is cyclic and is not radial led us to think that a model including kinematic hardening would be better adapted for the modelling of shot peening. In this article we present the results of a simulation of a double impact for several constitutive laws. We study the effect of the chosen constitutive law on the level of residual stresses and, in particular, we show that kinematic hardening, even identified on the same tensile curve than isotropic hardening, leads to lower stress levels as compared with isotropic hardening. Furthermore, the overall shape of the stress distribution within the depth is significantly different for the two types of hardening behaviour. Further, in order to check the modelisations, local measurements were carried on with X-ray diffraction on a large size impact and correlated with the topography of the impact.

EFFECT OF HEAT TREATMENT ON MICROSTRUCTURE AND CORROSION RESISTANCE OF Ni-B-W-Mo COATING DEPOSITED BY ELECTROLESS METHOD

2018 ◽  
Vol 25 (08) ◽  
pp. 1950023 ◽  
Author(s):  
ARKADEB MUKHOPADHYAY ◽  
TAPAN KUMAR BARMAN ◽  
PRASANTA SAHOO
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electrochemical Techniques ◽  
Sodium Molybdate ◽  
Medium Carbon Steel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid Solution Strengthening ◽  
Heat Treated ◽  
Electroless Coatings

The present work reports the deposition of a quaternary Ni-B-W-Mo coating on AISI 1040 medium carbon steel and its characterization. Quaternary deposits are obtained by suitably modifying existing electroless Ni-B bath. Composition of the as-deposited coating is analyzed by energy dispersive X-ray spectroscopy. The structural aspects of the as-deposited and coatings heat treated at 300[Formula: see text]C, 350[Formula: see text]C, 400[Formula: see text]C, 450[Formula: see text]C and 500[Formula: see text]C are determined using X-ray diffraction technique. Surface of the as-deposited and heat-treated coatings is examined using a scanning electron microscope. Very high W deposition could be observed when sodium molybdate is present in the borohydride-based bath along with sodium tungstate. The coatings in their as-deposited condition are amorphous while crystallization takes place on heat treatment. A nodulated surface morphology of the deposits is also observed. Vickers’ microhardness and crystallite size measurement reveal inclusion of W and Mo results in enhanced thermal stability of the coatings. Solid solution strengthening of the electroless coatings by W and Mo is also observed. The applicability of kinetic strength theory to the hardening of the coatings on heat treatment is also investigated. Corrosion resistance of Ni-B-W-Mo coatings and effect of heat treatment on the same are also determined by electrochemical techniques.

scholarly journals A microstructural and corrosion resistance study of (Zr, Si, Ti)N-Ni coatings produced through co-sputtering

DYNA ◽  
2018 ◽  
Vol 85 (207) ◽  
pp. 192-197 ◽  
Author(s):  
Estrella Natali Borja-Goyeneche ◽  
Jhon Jairo Olaya-Florez
Keyword(s):  
Corrosion Resistance ◽  
Nickel Content ◽  
Corrosion Current ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Current Densities ◽  
Fcc Phase

This work researches the influence of the nickel content on the structural and anticorrosive properties of ZrSiTiN films deposited by means of reactive co-sputtering on alloys of Ti6Al4V. The morphology and structure were analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the chemical composition was identified via X-ray scattering spectroscopy (EDS). The corrosion resistance was studied using potentiodynamic polarization (PP) tests employing a 3.5% by weight NaCl solution. In the films, an increase of Ni up to 6.97 at% was observed, while in XRD the FCC phase of (Zr, Ti) N was identified, with a mixed orientation in planes (111) and (200), which tended to diminish with the increase of Ni. Finally, with the addition of Ni, the corrosion current densities were reduced from 5.56 𝑥 10−8 to 2.64 𝑥 10−9 𝐴/𝑐m2. The improvement in the corrosion resistance is due to the effect of the Ni on the microstructure of the system (Zr, Ti) N, which can improve the quality of the passive film and prevent crystalline defects and corrosion zones.

The Effects of Mn Addition on Microstructure and Properties in 6061 Aluminium Alloy

2011 ◽  
Vol 399-401 ◽  
pp. 1838-1842
Author(s):  
You Bin Wang ◽  
Jian Min Zeng
Keyword(s):  
Heat Treatment ◽  
Aluminium Alloy ◽  
X Ray Diffraction ◽  
6061 Aluminum Alloy ◽  
X Ray ◽  
T6 Heat Treatment ◽  
Hardness Tester ◽  
Mn Content ◽  
The Mean ◽  
6061 Aluminium Alloy

The effects of Mn addition on the microstructure and hardness of 6061 aluminum alloy were studied by means of scanning electron microscope (SEM) , energy dispersive X-Ray Analysis (EDX), X-ray diffraction (XRD) and hardness tester in this work. The results shows that rod and fishbone AlSiFeMn phase will be formed in the alloy with Mn addition in 6061 aluminium alloy, and the AlSiFeMn phase increases with the increasing of Mn content . By the mean of XRD, the Al4.07 Mn Si0.74 phase is found in the 6061 aluminium alloy from 0.7% to 1.5% Mn. The hardness increases with the increasing of Mn contents both for as-cast and for T6 heat treatment. However, the hardness growth rate for as-cast is much more than that for T6 heat treatment at the same Mn addition in the 6061 alloy. Mn has a little effect on the hardness for T6 heat treatment in 6061 alloy.

Research on Properties of Amorphous Cr-C Alloy Coating in Crystallization Evolution

2012 ◽  
Vol 184-185 ◽  
pp. 1175-1180
Author(s):  
Guo Liang Li ◽  
Xiao Hua Jie ◽  
Bi Xue Yang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Intermetallic Compound ◽  
Adhesion Force ◽  
Alloy Coating ◽  
Treatment Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Proper Values ◽  
Peak Value

Amorphous Cr–C alloy coating was prepared by electrodepositing. The microhardness of the coating was tested after annealing from 100°C to 800°C and the crystallization evolution was studied by the analysis of X-ray diffraction (XRD) and differential scanning caborimetry (DSC). The results showed that the crystallization evolution of the coating began at 300°C and finished around 450°C, and intermetallic compound Cr7C3and Cr23C6appeared when heat treatment temperature reached around 600°C. The microhardness, corrosion resistance as well as the adhesion of the coating all increased first with the temperature and then dropped until it attained the proper values. The microhardness reached the maximum of 1610HV0.025at 600°C. While the corrosion resistance and the adhesion force attained the peak value at about 400°C.

Electrochemical behavior and corrosion resistance of electrodeposited nano-particles Zn-Co-Fe alloy

2015 ◽  
Vol 63 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Mortaga Abou-Krisha ◽  
Fawzi Assaf ◽  
Omar Alduaij ◽  
Abdulrahman G Alshammari ◽  
Fatma El-Sheref
Keyword(s):  
Corrosion Resistance ◽  
Ternary Alloy ◽  
Binary Alloys ◽  
Linear Sweep Voltammetry ◽  
Nano Particles ◽  
X Ray Diffraction ◽  
Surface Appearance ◽  
Content Type ◽  
X Ray ◽  
Anticorrosion Properties

Purpose – The purpose of this study was to compare the electrodeposition behavior and corrosion resistance of ternary and binary alloys. Design/methodology/approach – Potentiodynamic polarization resistance measurement and anodic linear sweep voltammetry techniques were used for the corrosion study. The surface morphology and chemical composition of the deposits were examined using scanning electron microscopy and atomic absorption spectroscopy, respectively. The phase structure was characterized by X-ray diffraction analysis. Electrodeposition behavior was carried out using cyclic voltammetry and galvanostatic techniques. Findings – It was found that the obtained ternary alloy exhibited better corrosion resistance and a more-preferred surface appearance compared to the binary alloys that were electrodeposited under similar conditions. Research limitations/implications – The ternary alloy showed better anticorrosion properties compared to binary deposits that were electroplated successfully from the plating baths. The Zn-Co-Fe alloy could be used advantageously in industry because the ternary alloy exhibits the collective properties of the binary alloys in one alloy via the electrodeposition of Zn-Ni-Co alloy. Social implications – Increasing the corrosion resistance implies to social economic increases. Originality/value – To date, the electrodeposition of Zn-Co-Fe alloy was studied in only a small number of articles. It was found that the presence of Co or Fe could provide a useful coating on the steel that would reduce its susceptibility to corrosion attack.

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.

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