Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : corrosion


Effect of Adding Silver Element and Zirconia Ceramic on Corrosion Behavior and Mechanical Properties of Pure Titanium

Wehad A. Al-Rawy; Emad S. Al-Hassani

Engineering and Technology Journal, 2021, Volume 39, Issue 5A, Pages 674-694
DOI: 10.30684/etj.v39i5A.1087

In this research, all the samples are prepared using the powder metallurgy technique by adding silver element and Zirconia ceramic material to the commercially pure titanium at a different weight percent of (10, 20 and 30) to investigate the effect of adding these materials to the CP-Ti on corrosion behavior and mechanical properties. There are two sets of each type of alloys Ti-Ag and Ti ZrO2. The Preparation process was by Weighing, Mixing and Homogenizing Powders by Ball Mill, compacting at 4 tons for 1 min. and Sintering at 700 and 900 °C for 2 hrs. under a controlled atmosphere. The corrosion results showed a good corrosion resistance increases with increasing the silver content as the corrosion rate would be the best in (30% Ag) content with(0.091 mpy) at sintering temperature of 700 °C. And with a sintering temperature of 900 °C, the best result was with (30% Ag) with (0.059) mpy. In the Ti-ZrO2 alloys, the best result was with the zirconia content of (30%ZrO2) when cooled in the air with (1.347) mpy at sintering temperature of 700 °C, this results obtained in Ringer’s solution. And microstructures analysis stated that at the silver and the Zirconia content of (10-20 wt%) single phase of  (α- Ti alloy), as the silver and Zirconia content increased to (30% wt), in addition to (α-phase), (Ti2Ag) intermetallic compound developed in the silver alloy microstructure and (TiZr)3O intermetallic compound developed in the microstructure of Ti- Zirconia composites and the hardness test result best hardness of  titanium-silver alloys is with a silver content of (30% Wt) at sintering temperature of 900 C.

Electrochemical Characteristics of High-Volume Fly Ash Lightweight Aggregate Concrete Incorporating Hydrated Lime

Tareq S. Al-Attar; Basil S. Al-Shathr; Mahmood E. Mohammed

Engineering and Technology Journal, 2020, Volume 38, Issue 11, Pages 1629-1639
DOI: 10.30684/etj.v38i11A.1550

Currently, the use of high-volume fly ash lightweight concrete, HVFALWC, has acquired popularity as a durable, resource-efficient, and an option of sustainability for varying concrete applications. Electrochemical characteristics such as half- cell potential, AC resistance, chloride penetration, free chloride, and pH value, up to 180 days were investigated for this type of concrete that uses 50% and 60% of fly ash as a replacement of Portland cement. The effect of using 10% hydrated lime powder as a partial substitute for the weight of cementitious materials for HVFALWC on electrochemical properties was also studied. The results in this study showed the possibility of producing friendly environmental structural lightweight concrete by using high volume fly ash (50% and 60%) as partial replacement by weight of cement. Furthermore, using 10% hydrated lime as partial replacement by weight of cementitious materials could be considered as a reliable measure to reduce the effect of chloride ions in the corrosion process

Compressive Performance of Corroded Reinforced Concrete Columns

Mushtaq S. Radhi1; maan s. hassan; Iqbal N. Gorgis

Engineering and Technology Journal, 2020, Volume 38, Issue 11, Pages 1618-1628
DOI: 10.30684/etj.v38i11A.1545

Corrosion of reinforcement has been identified as the deterioration mechanism of reinforced concrete structures, which seriously affects the safety and integrity of structures. The corrosion of the embedded reinforcing steel in concrete is a major problem facing civil engineers today, which initiates 80% of the reinforced concrete structures deterioration. This paper reveals the outcomes of an experimental investigation on the mechanical performance (residual strength) of circular steel reinforced columns which have been damaged by corrosion of the steel rebar. Small scale circular reinforced concrete columns with a diameter of 100 mm and 300 mm in height were adopted. Different rates of steel reinforcement mass loss (corrosion damage) ranged between 10%, 20% to 30 % were created in the columns by using a galvanostatic accelerated corrosion method combined with wetting-drying cycles. The uniaxial compression test was implemented for damaged columns up to failure. Based on the experimental outcomes, it was revealed that the corrosion damage had substantially reduced the performance of columns. The decrement of the load capacity of corroded columns ranged between 19% to 40% and for corrosion level ranged from 10% to 30%, respectively. The decrement of the final deformation of corroded columns ranged between 15% to 30% and for corrosion level ranged from 10% to 30%, respectively. Likewise, the failure mode and relationship between the stress and strain for corroded columns had been adversely affected by corrosion.

Preparation of a Reinforced Polymeric Coating with Inorganic Nano Additives as UV-Stabilizers and Protect Oil Pipelines from Corrosion

I.A.Esmael; F.M.Ahmed; N.F.Ibraheem; H.M.Yas; L.H.Thuaban

Engineering and Technology Journal, 2017, Volume 35, Issue 10, Pages 1003-1010

In this research a nano polymeric coating has been prepared to be used for the protection of the external surface of oil pipelines (medium carbon steel (CK50)) from corrosion in salt water (3.6% NaCl) . This coating is reinforced by inorganic (nano and micro) additives to apply a high resistance against chemicals and salts. These oxides protect the epoxy resin from degradation by preventing the epoxy molecules and active functional groups from absorbing ultraviolet light in the range (290-315) nm strongly.This coating is also resistant to the high and low temperatures, humidity, scratch and water. This coating was prepared from the reaction of 2-[[4-[2-[4-(Oxiran-2-ylmethoxy) phenyl] propan-2-yl] phenoxy] methyl] oxirane (Diglycidyl Ether of Bisphenol A) and the hardener (EDA). The mixing ratio of the two parts was (4:1). Reinforced with inorganic (nano and micro) additives such as titanium dioxide (TiO2) and zinc oxide (ZnO) which have been used as an anticorrosion. These additives are non-toxic, thermally stable and have a high degree of the miscibility with epoxy. The weight percentages of the mixing are (0 and 10 % wt). The corrosion rate results show that using (nano and micro) coating give good results in increasing the corrosion resistance compared with the (non additives) epoxy.This coating was characterized using different spectroscopic methods (FT-IR, UV/Vis). Several tests were conducted ,
including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) , mechanical tests and evaluation of corrosion resistance was made by using static potential test.

Corrosion of Gold Thin Films Deposited by Sputtering Deposition Method

Haitham M. Wadul; Muna Khethier Abbass; Sami Abualnoun Ajeel

Engineering and Technology Journal, 2015, Volume 33, Issue 6, Pages 1145-1153

Gold thin films have been prepared and deposited by sputtering deposition system at 17 nm and 34nm thicknesson Ni-Cr-Mo alloy substrate.SEM, AFM, XRD, and Spectroscopic Reflectometer were used to characterize the thin films deposited. Electrochemical corrosion tests also have been carried out by measuring open circuit potential (Eo.c.p), Tafel extrapolation and cyclic polarization methods in artificial saliva solution at 37 0C with elements analysis of the corrosion solution by using atomic absorption spectroscopy (AAS). The results obtained indicate the ability to deposit gold thin films (17nm and 34 nm ) by sputtering deposition methodonNi-Cr-Mo alloy with uniformity and without defects, decreasethe roughness from 2.54 nm to 1.8 nm for gold nanocoated with 34nm and 17 nm respectively, FCC crystalline structure (111) with diffraction peaksresults from XRD, and improvement of the localized corrosion resistance by decreasing the hysteresis loop of nanocoated with 34 nm of gold compared with the uncoated alloy

Study of Erosion- Corrosion Behavior of Aluminum Metal Matrix Composite

Muna K. Abbass; Mohammed Abdulateef Ahmed

Engineering and Technology Journal, 2014, Volume 32, Issue 3, Pages 406-417

The aim of present work is to study the erosion –corrosion behavior of aluminum metal composite which consists of the (Al – 12wt % Si) alloy as matrix phase and 10wt% SiC particles as reinforcing phase. Composite material was prepared by stir casting using vortex technique. A general corrosion and erosion-corrosion for the base alloy and the prepared composite were carried out in 3.5wt% NaCl solution as corrosive medium for general corrosion while in erosion-corrosion ,with varying impact angles (0° ,30° ,45° and 90°) in slurry solution ( 1wt%SiO2 sand in 3.5wt% NaCl solution as the erodent).
It was found that the general corrosion rate for composite specimen is lower than that of the base alloy (Al-12%Si). In case of erosion-corrosion results, it was found that the weight loss rate or corrosion rate in (gmd) unit at impact angle (0°) is lower than that of other impact angles for the base alloy and composite material.

Cathodic Protection for Steel Pipeline Using Solar Energy

Sami I. J. Al-rubaiey; Naser Korde Zed

Engineering and Technology Journal, 2014, Volume 32, Issue 1, Pages 154-161

The present work involves using Impressed Current Cathodic Protection
Technique (ICCPT), to prevent corrosion of buried underground steel pipelines.Polarization method using galvanokinetic technique was used to study the behavior of steel pipelines in Iraqi soil. The soil resistivity in this work is equivalent to NaCl solution (5, 10, 15, 20 and 25) NaCl concentrations. The resistivities play a strong role in corrosion rates, where corrosion rate increases with decreasing environment resistivity and increases with increasing the concentrations of NaCl for constant surface area. The object of this study is using a cathodic protection system by impressed current supplied with solar energy panels applied to steel pipelines. The efficiency of cathodic protection depending on the soil resistivity in the present
work with different electric source and solar energy source are reached to the (92.3-94.5).

Experimental and Numerical Study of CO2 Corrosion in Carbon Steel

Dalia M. Jomaa; Ali H. Jawad; Rana A.Majed

Engineering and Technology Journal, 2013, Volume 31, Issue 15, Pages 2885-2904

This research involves study corrosion of low carbon steel under static and flow
conditions at 200L/h in the absence and presence of CO2 at two rates 9 and 30 ml/min
at four temperatures by electrochemical method using potentiostat. Numerical model
was achieved to compare between the experimental and theoretical results to estimate
corrosion rate. The results show that the presence of CO2 under static conditions
shifts the Ecorr toward noble direction, while under flow condition the presence of CO2
shift Ecorr toward active or noble direction at two rates of gas. The data of corrosion
rate in mm/y indicate that the presence of CO2 with two flow rate increased the rate
compared with the case of absence of CO2 under static conditions except one case,
while under flow conditions, the presence of 9 ml/min. CO2 increases the corrosion
rate, while the presence of 30 ml/min. CO2 decreases the rate because of formation
FeCO3 scale except at 298K. A Mathematical model was done which show the
volumetric flow rate of CO2 and finally the corrosion rate of CO2 correlated with
dimensionless groups and independent parameters.

Comprehensive Electrochemical Evaluation of Protective Coatings Properties by Sol-Gel Route for Stainless Steel Corrosion

Atia; Mohammed Hussein J. Al

Engineering and Technology Journal, 2013, Volume 31, Issue 4, Pages 71-86

Sol gel nano ceramic coatings have been applied on stainless steel to develop their biological characteristics and increase resistance to corrosion and wear. In this work nine electrochemical parameters were calculated, adopted to set a comprehensive evaluation map for protective properties of the coatings obtained based on occurrence degree of cracks, porosity, general and localized corrosion by using d.c. Potentiostate utilized for measuring the polarization curve in 3.5% NaCl solution at 250C for a single alumina layer deposited on stainless steel specimens by the dipping technique from four solutions containing different alumina concentration 0.25, 0.26, 0.61 and 0.93 mole/liter prepared by dissolving aluminum isopropoxide in water, the coats were then heat treated to 6000C. The results showed the possibility of obtaining clear protective properties that facilitate the comparison between the types of thin coatings deposited on the surfaces of the stainless steel by sol gel method.

Optimum Effect of Factors Influencing on Sacrificial Cathodic Protection for Steel Wall

Mohammad H. Hafiz; Wissam K. Hamdan; Saad E. Kaskah

Engineering and Technology Journal, 2012, Volume 30, Issue 18, Pages 3154-3163

The Box-Behnken Design (BBD) is used to model the sacrificial Cathodic
Protection System (SCPS) to find the factors effectiveness behaviour. For protection
potential assessment the BBD receives (resistivity of environment, sacrificial anode
alloy, distance between anode and cathode and surface area for the structure to be
protected) as input and gives the protection potential as output. By applying BBD
with their analysis tools we get many results. The important results which are the
factors individual effectiveness on the sacrificial cathodic protection (SCP) process
are the resistivity which has the greatest effect on the potential protection (rank=1)
followed by sacrificial anode alloy type (rank=2), surface area for structure protected
required (rank=3) and distance between anode and cathode (rank=4). The interaction
of sacrificial anode alloy and cathode area (χ2χ4) has significant effect on CP process
with the limits which are used in this work while the other factors interaction (χ1χ2,
χ1χ3, χ1χ4,χ2χ3, χ3χ4) has insignificant effect on the limits which used in this work.

Applying Non-linear Damage Model for Predicating Corrosion Effect on Fatigue Life of (carbon + glass) Fibers / PMMA Composite

Husin .J.M. Al-Alkawi; Amer Hameed Majeed; Saisaban Ali Fahad

Engineering and Technology Journal, 2012, Volume 30, Issue 16, Pages 2898-2909

The objective of this work is to investigate the salt water effects on fatigue
degradation, and stress-life relationship. A series of reversed fatigue experiments were
conducted on (carbon+ glass) / PMMA of salt water environments. Results indicate that
the composite degrade during cycling. Exposure to salt water (salt water is used to
simulate the sea water) provides the most significant reduction in fatigue life. The
corrosion environment reduces the fatigue strength by 61% compared to dry fatigue.
Based on previous damage model [16], corrosion – fatigue nonlinear damage model is
presented in this paper, which contains one material constant; the inverse slope (α) of the
S-N curve. Six specimens of two levels loading of composite material were used to verify
the present model; the results showed that the predicted life is in good agreement with the
experimental results.

Study the Microbiologically Influenced Corrosion of Carbon Steel

Zuheir T.Khulief.Al-Tai

Engineering and Technology Journal, 2011, Volume 29, Issue 15, Pages 3141-3157

The main objective of this study was to evaluate the microbiologically
influenced corrosion of carbon steel in water, samples of water taken from Al-Hilla rivers and distill water (control medium ). Corrosion analyses by using (Liner polarization tafel test; weight loss method ; microstructure examination , surface roughness test and X-Ray diffraction analysis) and microbiological analyses by using
(Isolation and identification by using appearance factors microscopic ,culturing factors and biochemical tests for biofilm of corrosion product) are used in this study. The result of corrosion analyses shows the corrosion rates of carbon steel in rivers water are more than that in control water, the microstructure examination and surface roughness tests show increase in roughness of met.al. surfaces which are
under the corrosion medium (rivers water) compared with control medium. The result of microbiological analyses shows the slides that made from the biofilm (product of corrosion) under microscopic appear small bacilli negative gram strain (G-ve) bacteria, where as culturing test shows small colonies with 2.5ìm in diameter of bacteria have mucin appearance and green pigments as well as the result from
biochemical tests; these facts indicate that Pseudomonas aeruginosa bacteria are correlated with the type of corrosion occurring in the carbon steel in the rivers water.

Galvanic Cathodic Protection Evaluation of a Steel Pipe in Iraqi Soil

Jafer T. Al-Haidary; Mohammed H. Hafiz; Yasir Muhi Abdu Al-Sahib

Engineering and Technology Journal, 2011, Volume 29, Issue 9, Pages 1673-1690

Corrosion is the main problem for the embedded pipelines in different
environment resistivities. The most effective method to overcome this problem is
cathodic protection which represents as a control method of the pipe corrosion.
For achieving longer life of the external corrosion control system and evaluating
the performance of aluminum alloys which have been used as sacrificed anodes
to protect the embedded carbon steel pipe in different artificial simulated
resistivity of soils in Iraq of [5000 , 1000 , 600 , 50 and 25 (Ω.cm)]. Results show
that (Al-10 wt% Zn) as sacrificial anode alloy has the best anode capacity
compared with other anodes under these conditions (Al-5 wt% Zn), and (Al-15
wt% Zn). The selection for these alloys based on that they have high potential in
many environments when coupling with steels without effect of microbial,
obstacle and stray current. The polarization curves of alloys also show no
passivation behavior in artificial resistivities. The corrosion rate of different anode
alloys was determinated as a function of applied cathodic protection.
It was found a relationship between electric potential and time which
determine the optimum potential in different soil types for the three above selected
electrodes (anodes).

Influence of Corrosion Rate on the Double Butt Welding Shapes Design for Low Carbon Steel

Hani Aziz Ameen; Khairia Salman Hassan; Walid Khalid Abdul Kader

Engineering and Technology Journal, 2011, Volume 29, Issue 6, Pages 1094-1106

The aim of this paper is to demonstrate the influence of butt welding shapes
on the corrosion rate, microstructure and temperature of carbon steel type
St37.The double butt welding was performed by V angles 15°,30° and 45°. The
finite element analysis via ANSYS software is performed, this analysis includes a
finite element model for the thermal welding simulation. The temperature
distribution was obtained. From the results of the microscopic structure it is
evident that the geometric shape has an important role in the welding process,
when the geometric value of the welding region gets bigger, the faults get less due
to increase of heat quantity in the welding region and the corrosion rate for the
rain water is less than of sea water. The work presents the finite element model for
numerical simulation of welding in carbon steel St37 double butt welding.

Study of Corrosion Behavior of Metal Matrix Composite Based on Al-Alloy (7020) Prepared by Atomization

Muhammad S. Waheed; Muna K. Abbass

Engineering and Technology Journal, 2010, Volume 28, Issue 8, Pages 1502-1514

An experimental procedure has been fully formulated and carried out to
prepare composite material of an aluminum (alloy 7020) matrix reinforced by Al2O3 particles with weight percentages of 5%, 7% and 10% and its particle size of (+53-75)μm using molten metal atomization technique. These experiments involve the preparation of aluminum matrix composite (AMCS) materials and study their Corrosion resistance in 3.5% solution of NaCl at temperature degrees 30˚C, 38˚C and 45˚C using various testing techniques. These include electrochemical corrosion and optical microscopy .
The corrosion rate was found to increase as the temperature was nominally raised from 30˚C to 38˚C and 45˚C for the 10%wt of alumina in atomized AMCS samples in 3.5% NaCl solution. At a temperature of 30˚C the corrosion rate was found to rise with increasing percentages of Al2O3 particles for 5%, 7% and 10% atomized samples. This is due to galvanic corrosion between the matrix and the second phases (MgAl2O4) and (MgO) in microstructure of AMCS. Optical microscope showed a profound appearance of general corrosion in all microstructural area and grain boundaries.

An Investigation of the Inhibition of the Oxygen Reduction Reaction at a Rotating Cylinder Electrode under Isothermal and Controlled Conditions of Heat and Mass Transfer

Shatha. A. Sameh; Sadiq. H. Alwash

Engineering and Technology Journal, 2009, Volume 27, Issue 5, Pages 930-941

The inhibition of the oxygen reduction reaction on a carbon steel rotating
cylinder electrode in naturally aerated 600 ppm Cl- solution was studied using an
optimum inhibitor blend, i.e., Sodium Nitrite (SN): Sodium Hexametaphosphate
(SHMP) = 500:100 obtained via a weight loss technique. Potentiostatic technique, then,
was applied at different bulk temperatures and various flow rates using un-inhibited and
inhibited solutions under isothermal and controlled conditions of heat transfer.
In an un-inhibited solution and under isothermal conditions, with limiting conditions of
concentration polarization, the limiting current density of oxygen reduction reaction is
flow and temperature dependent. The charge transfer of the oxygen reduction reaction is
a 4 electron process in the range of bulk temperature employed from 303 to 323 K.
Under heat transfer conditions, the charge transfer is still 4 electron process up to 336 K
interfacial temperature, above which the contribution of the 2 electron process appeared.
Moreover, the limiting current density values of the oxygen reduction reaction in
inhibited solutions is much lower than those under identical conditions in un-inhibited
solutions. This confirms the inhibition of the cathodic reaction, i.e., the oxygen
reduction reaction under isothermal and heat transfer conditions, due to SHMP.

Corrosion of Copper in Deaerated and Oxygenated 0.1M H2SO4 Solutions under Controlled Conditions of Mass Transfer

Shatha A.Sameh; Issam K.Salih; Sadiq H.Alwash; AsawerAL-Waisty

Engineering and Technology Journal, 2009, Volume 27, Issue 5, Pages 993-1007

The corrosion behavior of copper in deaerated and oxygenated 0.1 H2SO4
solutions has been investigated using the rotating cylinder electrode under turbulent
flow conditions. Potentiostatic polarization measurements were carried out at different
bulk temperatures of 283, 288, 293 and 298 K and various speeds of rotation viz 100,
200, 300 and 400 r.p.m. The anodic dissolution of copper and the hydrogen evolution
reaction, in deaerated and oxygenated solutions, are activation controlled processes
dependent on the temperature of the solution. The anodic dissolution of copper is not
mass transfer controlled. The results are consistent with a mechanism which suggests
that oxidation of copper takes place in two steps of one electron each. The second step,
i.e., cuprous ion (Cu+) oxidation, is the rate controlling. Moreover, the mechanism of
hydrogen evolution reaction is a proton discharge upon the metal surface. The charge
transfer of the oxygen reduction reaction is a 2e process in the range of bulk
temperatures employed, i.e., the oxygen reduction is controlled by 2e process.
Furthermore, the limiting current density value of the oxygen reduction reaction
increases as the velocity of the fluid increases. The results, at a constant bulk
temperature are consistent with Eisenberg et al theory for mass transfer to a rotating
cylinder electrode surface

Fusion Face and Palmprint for Human Recognition via Spectral Eigenvector

Hana; a M. Salman

Engineering and Technology Journal, 2009, Volume 27, Issue 4, Pages 787-798

The Biometrics recognition systems act as an efficient method with broad
applications in the area of: security access control, personal identification to humancomputer
communication. From other hand, some biometrics have only little variation
over the population, have large intra-variability over time, or/and are not present in all
the population. To fill these gaps, a use of multimodal biometrics is a first choice
solution [1].
This paper describes a multibiometrics method for human recognition based on
new teacher vector identified as spectrum eigenface, and spectrum eigenpalm. The
proposed combination scheme exploits parallel mode capabilities of the fusion feature
vectors in matching level and invokes certain normalization techniques that increase its
robustness to variations in geometry and illumination for face and palmprint. The
correlation distance is used as a similarity measure. A threshold value is used to
prevent the imposter for being recognized. Experimental results demonstrate the
effectiveness of the new method compared to the unimodal biometrics for spectrum
eigenface/eigenpalm.

Modeling Time to Corrosion Initiation in High-Performance Ferrocement Exposed to Chlorides Environments

J. Forth; Maan S. Hassan; S. A. Salih

Engineering and Technology Journal, 2009, Volume 27, Issue 1, Pages 18-31

The applications of a mineral admixture, or a zinc coating to steel surface, or a
combination of both are methods used for the corrosion prevention of ferrocement
element in this study. Results of a study to evaluate many corrosion protection systems
with metakaolin and/or galvanized steel mesh are presented in six U-shaped specimens.
Specimens were built to simulate exposure conditions typical for marine environment.
Laboratory data collected along duration of 40 weeks of exposure were used in
modeling the cover depth as a function of time to corrosion initiation of the investigated
corrosion prevention methods. Methods used to assess the condition of specimens
included chloride concentration measurements, and corrosion rates. Model predictions
show that the ferrocement specimen of high-performance mortar with metakaolin
provides much better level of protection against moisture and chlorides than the
conventional specimen, by delay rate of chloride ingress. Application of a galvanized
steel mesh causes an elevation of the chloride threshold resulting in an additional
increase in the predicted time to corrosion initiation.

Oxidation and Corrosion Mechanism of Steel Alloys and Inconel 600 Alloy in Liquid–Lead-Bismuth Eutectic

Ahmed Moosa

Engineering and Technology Journal, 2008, Volume 26, Issue 11, Pages 1369-1383

The alloys used in this study were two types pf stainless steels (304SS and
316 SS) , low alloy steel (Type T22-ASTM) and Inconel 600 alloy `(nickelbase
superalloy). The oxidation mechanism were studied for three steel
alloys and for inconel 600 in liquid Pb-Bi eutectic (LBE) in the temperature
range 450- 550 oC using stagnant test . A model based on the experiments
of Cr oxidation at high temperature with scale vaporization was applied to
the present oxidation process by replacing the vaporization rate with the
mass-transfer-corrosion rate. The results indicate that all steel alloys
showed an oxidation/corrosion behavior. The oxidation kinetics is parabolic
and the corrosion kinetics is linear. The parabolic oxidation rate constant
are of the following order (Kp) 304SS (Kp) 316SS > (Kp) low alloy steel .
The scale-removal-rate constants Kr by mass transfer corrosion are of the
following order (Kr) inconel > (Kr) 316SS > (Kr) 304SS . The weight loss
increases with increasing Ni content in the steel alloys.

Improvement of Hot Galvanizing By Nickel Under Layer

Mohammed Hliyil Hafiz

Engineering and Technology Journal, 2008, Volume 26, Issue 6, Pages 689-698

Zn–Ni alloy based coatings have high corrosion resistance, good adherence and
unique physical as well as mechanical properties. In the present work, nickel was
dispersed in the under layer of hot dip zinc coating (Galvanizing). showed substantial
improvement in physical as well as galvanic performance. The presence of nickel in the
under layer was found to result in good adherence, less porosity and better hardness .The
presence of nickel decreases the thickness of the coating and enhances the corrosion
resistance character.

Galvanic Corrosion Behavior of Electroless Nickel Coating in Al-Zubare Harbor-Water

Mohammed Hliyil Hafiz

Engineering and Technology Journal, 2007, Volume 25, Issue 9, Pages 1056-1063

Electrode potentials in AL-Zubare harbor water (South -Gas Company),
of 23.88 ohm-cm at 20oC were reported for 26 metals and alloys including
values for electroless nickels that signify a greater passivity than steel. The
large potential difference between steel and electroless nickel predicts severe
galvanic corrosion, which was confirmed by weight loss data for coupled steel
and electroless nickel electrodes immersed in AL-Zubare Harbor water
(South -Gas Company, 23.88 ohm-cm at 20oC) .Changes in the phosphorous
content in the range of 7.10 to 12.45 percent had only a slight effect on the
electrode potential of electroless nickel.
This study indicates the beneficial use of electroless nickel coating is more
passive than other (metals and alloys) and that galvanic corrosion of active
metals such as steel can be severe .