Corrosion Behaviour of Anodised Powder Metallurgy Aluminium-Magnesium Composites

2013 ◽  
Vol 795 ◽  
pp. 469-473
Author(s):  
Kamrosni Abdul Razak ◽  
Mohd Nazree Derman
Keyword(s):  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Sulphuric Acid ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Corrosion Behaviour ◽  
Short Fibre ◽  
Acid Solutions ◽  
Powder Metallurgy Route ◽  
Magnesium Composites

The corrosion behavior of anodized powder metallurgy Al/2wt%Mg composites reinforced with the short fibre alumina SaffilTM was studied using potentiodynamic polarization in 3.5% NaCl solutions. The materials under investigation were fabricated using powder metallurgy route. Anodising process has been done to the materials to improve their corrosion resistance. Anodising process were carried out in sulphuric acid solutions with different anodizing voltage, which are 10V, 12V, 14V, 16V and 18V and different concentration of sulphuric acid (5%, 10%, 15%, 20% and 25%). Results from Tafel plot showed that corrosion behavior of PM Al-Mg composites strongly depends on the anodizing parameters. Corrosion resistance increases with the increase in anodizing voltage and concentration of sulphuric acid. The maximum corrosion resistance was recorded by the PM Al-Mg composite anodized using 16V and in the 15% concentration of sulphuric acid.

Role of Aluminium on the Microstructure and Corrosion Behaviour of Magnesium Prepared by Powder Metallurgy Method

2020 ◽  
Vol 17 (3) ◽  
pp. 8206-8213
Author(s):  
J. Alias
Keyword(s):  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Corrosion Behaviour ◽  
Corrosion Current ◽  
Optical Microscope ◽  
High Reactivity ◽  
Aluminium Content ◽  
Powder Metallurgy Method ◽  
X Ray Diffraction ◽  
Promising Development

Much research on magnesium (Mg) emphasises creating good corrosion resistance of magnesium, due to its high reactivity in most environments. In this study, powder metallurgy (PM) technique is used to produce Mg samples with a variation of aluminium (Al) composition. The effect of aluminium composition on the microstructure development, including the phase analysis was characterised by optical microscope (OM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The mechanical property of Mg sample was performed through Vickers microhardness. The results showed that the addition of aluminium in the synthesised Mg sample formed distribution of Al-rich phases of Mg17Al12, with 50 wt.% of aluminium content in the Mg sample exhibited larger fraction and distribution of Al-rich phases as compared to the 20 wt.% and 10 wt.% of aluminium content. The microhardness values were also increased at 20 wt.% and 50 wt.% of aluminium content, comparable to the standard microhardness value of the annealed Mg. A similar trend in corrosion resistance of the Mg immersed in 3.5 wt.% NaCl solution was observed. The corrosion behaviour was evaluated based on potentiodynamic polarisation behaviour. The corrosion current density, icorr, is observed to decrease with the increase of Al composition in the Mg sample, corresponding to the increase in corrosion resistance due to the formation of aluminium oxide layer on the Al-rich surface that acted as the corrosion barrier. Overall, the inclusion of aluminium in this study demonstrates the promising development of high corrosion resistant Mg alloys.

Studies and Research on the Corrosion Behavior of Ni-Al2O3 Compound Coatings Obtained by Electrochemical Methods

2020 ◽  
Vol 43 (3) ◽  
pp. 21-25
Author(s):  
Simona BOICIUC ◽  
◽  
◽  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Corrosion Behaviour ◽  
Composite Coatings ◽  
Point Of View ◽  
Electrochemical Methods ◽  
Dispersed Phase ◽  
Nickel Matrix ◽  
Technical Alumina ◽  
Compound Coatings

The undertaken research which is described in this paper aims at the corrosion behaviour of composite coatings in nickel matrix using as dispersed phase technical alumina with dimensions of 5 μm and their characterization from a microstructural point of view. The corrosion resistance in the saline fog of the coatings is influenced by the microstructure, the stresses developed in the layer and the roughness.

scholarly journals Erosion-Corrosion Protection Due to Cr3C2-NiCr Cermet Coating on Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1042
Author(s):  
Panneer Selvam Kevin ◽  
Abhishek Tiwari ◽  
Saravanan Seman ◽  
Syed Ali Beer Mohamed ◽  
Rengaswamy Jayaganthan
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
Turbine Blades ◽  
Continuous Exposure ◽  
Hydro Power ◽  
Cermet Coating ◽  
Erosion Corrosion

Cr3C2–NiCr coatings have been used extensively to combat the erosion corrosion of hydro power turbine blades made of stainless steel. Cr3C2–NiCr coatings are also used in aqueous corrosive environments due to the high corrosion resistance rendered by the NiCr binder. In this investigation, both erosion and corrosion environments are introduced to cermet coating to study corrosion behavior using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The cermet coatings are useful for reducing the risk of deterioration of mechanical properties of hydro power turbines due to the continuous exposure to the erosive and corrosive action of the corrosive environment containing silt. It was observed that Cr3C2–NiCr coating offered a reasonable improvement in corrosion resistance when compared to bare substrate. The corrosion behavior of the coating was studied in a 150 mL solution of 0.1 M NaCl with 2 gms of quartz particles (0.2–0.8 mm) at various rotation speeds (3000, 4500, 6000 rpm) of the solution over a 1 h immersion using potentiodynamic polarization and EIS studies in a specifically designed experimental set-up for erosion corrosion. When compared to the bare stainless steel samples at 3000 rpm and 6000 rpm, the coating showed the highest improvement at 6.57 times and the least improvement at 3.79 times, respectively.

Cermet ESD coatings modified by laser treatment

2012 ◽  
Vol 57 (3) ◽  
pp. 665-670 ◽  
Author(s):  
N. Radek ◽  
N. Konstanty
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Carbon Steel ◽  
Laser Treatment ◽  
Vickers Microhardness ◽  
Steel Substrate ◽  
Substrate Surface ◽  
Wear Resistant Coatings ◽  
Powder Metallurgy Route

The main objective of the present work was to determine the influence of laser treatment on microstructure, microhardness, roughness, bonding strength, corrosion resistance and tribological properties of wear resistant coatings produced on C45 carbon steel by the electro-spark deposition (ESD) process. Consumable WC-Co-Al2O3 electrodes were prepared by the powder metallurgy route and transferred to the substrate surface using the EIL-8A apparatus. The cermet layers were subsequently melted by means of the BLS 720 Nd:YAG laser. The coating characterisation studies showed marked improvements in the bonding between the steel substrate and the cermet coating, and in corrosion resistance at the expense of higher surface roughness and minor drop in the Vickers microhardness.

EFFECT OF FRICTION STIR PROCESSING ON CORROSION BEHAVIOR OF CAST AZ91C MAGNESIUM ALLOY

2019 ◽  
Vol 26 (06) ◽  
pp. 1850213 ◽  
Author(s):  
BEHZAD HASSANI ◽  
RUDOLF VALLANT ◽  
FATHALLAH KARIMZADEH ◽  
MOHAMMAD HOSSEIN ENAYATI ◽  
SOHEIL SABOONI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Friction Stir Processing ◽  
Potentiodynamic Polarization ◽  
Passive Layer ◽  
Friction Stir ◽  
T6 Heat Treatment ◽  
Az91c Magnesium Alloy

The corrosion behavior of as-cast AZ91C magnesium alloy was studied by performing friction stir processing (FSP) and FSP followed by solution annealing and then aging. Phase analysis, microstructural characterization, potentiodynamic polarization test and immersion tests were carried out to relate the corrosion behavior to the samples microstructure. The microstructural observations revealed the breakage and dissolution of coarse dendritic microstructure as well as the coarse secondary [Formula: see text]-Mg[Formula: see text]Al[Formula: see text] phase which resulted in a homogenized and fine grained microstructure (15[Formula: see text][Formula: see text]m). T6 heat treatment resulted in an excessive growth and dispersion of the secondary phases in the microstructure of FSP zone. The potentiodynamic polarization and immersion tests proved a significant effect of both FSP and FSP followed by T6 on increasing the corrosion resistance of the cast AZ91C magnesium alloy. Improve in corrosion resistance after FSP was attributed to grain refinement and elimination of segregations and casting defects which makes more adhesive passive layer. Increase in volume fraction of precipitations after T6 heat treatment is determined to be the main factor which stabilizes the passive layer at different polarization values and is considered to be responsible for increasing the corrosion resistance.

Corrosion Behaviour of Ti6Al4V and TiMo10Zr4 Alloys in the Ringer’s Solution: Effect of pH and Plastic Strain

2015 ◽  
Vol 227 ◽  
pp. 435-438 ◽  
Author(s):  
Joanna Loch ◽  
Alicja Łukaszczyk ◽  
Vincent Vignal ◽  
Halina Krawiec
Keyword(s):  
Corrosion Resistance ◽  
Plastic Strain ◽  
Titanium Alloys ◽  
Passive Film ◽  
Current Density ◽  
Potentiodynamic Polarization ◽  
Corrosion Behaviour ◽  
Ringer’S Solution ◽  
Ph Values

The corrosion behaviour of titanium alloys is not well understood – especially the role of the microstructure and plastic strain. In this paper, the influence of the microstructure and plastic strain on the corrosion resistance of TiMo10Zr4 and Ti6Al4V alloys was studied in the Ringer’s solution at 37 °C. Measurements were performed for different pH values and in aerated and de-aerated solutions using potentiodynamic polarization techniques. Results obtained on the two alloys were compared. It was shown that in the absence of plastic strain TiMo10Zr4 shows better corrosion resistance than Ti6Al4V (especially for pH = 8). By contrast, the current density in the passive range measured after 8% plastic strain was greater on TiMo10Zr4 than on Ti6Al4V, indicating that the passive film on TiMo10Zr4 is less protective than that formed on Ti6Al4V.

Effect of high temperature compression deformation strain rate on the microstructure and corrosion behavior of 2205 duplex stainless steel

2015 ◽  
Vol 62 (3) ◽  
pp. 163-171 ◽  
Author(s):  
Yinhui Yang ◽  
Biao Yan
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Strain Rate ◽  
Duplex Stainless Steel ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Phase Interface ◽  
Content Type ◽  
2205 Duplex Stainless Steel

Purpose – The aim of this paper was to investigate the effect of strain rate on microstructure and corrosion behavior of 2205 duplex stainless steel, after high-temperature compression tests. Design/methodology/approach – The specimens were prepared using a Gleeble3800 thermo-simulation machine over a range of temperatures from 850 to 1,250°C and strain rates from 0.005 to 5 s−1, and the corresponding flow curves and deformation microstructure obtained were further analyzed. To evaluate the effect of strain rate on corrosion behavior, potentiodynamic polarization tests and double-loop electrochemical potentiodynamic reactivation (DL-EPR) were used to characterize the electrochemical performance. Findings – Compared with strain rate of 0.5 s−1, the worst corrosion resistance behavior from the potentiodynamic polarization test results after deformation at 0.005 s−1 was attributed to more austenite (γ) and ferrite (δ) grain boundaries or δ/γ phase interface formation due to the better effect of γ dynamic recrystallization (DRX) or δ dynamic recovery (DRV). Increasing strain rate to 5 s−1 lowered the corrosion resistance, due to the increase in dislocation density. At the low strain rate of 0.005 s−1, the susceptibility to intergranular corrosion (IGC) was comparatively high after deformation at 1050 and 1150°C with more γ/γ grains and δ/γ phase boundary formation, which was lowered with the strain rate increase to 0.5 s−1, due to suppressing effect of γ DRX. Originality/value – The paper provides the scientific basis for the practical application of hot working of 2205 duplex stainless steel.

scholarly journals The effect of zinc bath temperature on the morphology, texture and corrosion behaviour of industrially produced hot-dip galvanized coatings

2014 ◽  
Vol 20 (1) ◽  
pp. 41-52 ◽  
Author(s):  
A. Bakhtiari ◽  
M.R. Toroghinejad ◽  
F. Ashrafizadeh
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Texture Component ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Bath Temperature ◽  
X Ray Diffraction ◽  
Zinc Bath ◽  
Compact Structure ◽  
Galvanized Coatings

The purpose of this work is to identify the influence of zinc bath temperature on the morphology, texture and corrosion behavior of hot-dip galvanized coatings. Hot-dip galvanized samples were prepared at temperature in the range of 450-480 °C in steps of 10 °C, which is the conventional galvanizing temperature range in the galvanizing industries. The morphology of coatings was examined with optical microscopy and scanning electron microscopy (SEM). The composition of the coating layers was determined using energy dispersive spectroscopy (EDS) analysis. The texture of the coatings was evaluated using X-ray diffraction. Corrosion behavior was performed using salt spray cabinet test and Tafel extrapolation test. From the experimental results, it was found that increasing the zinc bath temperature affects the morphology of the galvanized coatings provoking the appearance of cracks in the coating structure. These cracks prevent formation of a compact structure. In addition, it was concluded that (00.2) basal plane texture component was weakened by increasing the zinc bath temperature and, conversely, appearance of (10.1) prism component, (20.1) high angle pyramidal component and low angle component prevailed. Besides, coatings with strong (00.2) texture component and weaker (20.1) components have better corrosion resistance than the coatings with weak (00.2) and strong (20.1) texture components. Furthermore, corrosion resistance of the galvanized coatings was decreased by increasing the zinc bath temperature.

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