This document summarizes a study on measuring corrosion of metals in contact with wood. It discusses how corrosion occurs due to certain conditions like the presence of water and oxygen. The study examines different test methods used to measure corrosion rates of bolts, nuts and other fasteners when in contact with treated wood. Electrochemical impedance spectroscopy was used to analyze corrosion, and results were presented as Nyquist plots and tables. Higher moisture in wood leads to faster corrosion as it improves conductivity. While corrosion kinetics increase with temperature, thermodynamic tendency for corrosion decreases as it is an exothermic reaction.

1. SCHOOL OF MATERIALS AND MINERAL RESOURCES
ENGINEERING
2020/2021 SESSION II
EBB 316
CORROSION MEASUREMENT ON FASTENERS
(BOLTS AND NUTS)
GROUP MEMBERS:
NAME MATRIC NO.
Hanis bin Shamsuddin 143923
Mohammad Taufiq bin Mohamed Jawhar 143770
Muhammad Iman Rif’at bin Muhammad Sabri 144768
Periasamy Karthigan s/o Selvam 144440
LECTURER:
Assoc. Prof. Dr. Ahmad Azmin Mohamad

2. Corrosion Measurement On Fasteners In Contact With
Timber Application
Hanis bin Shamsuddin, Mohammad Taufiq bin Mohamed Jawhar,
Muhammad Iman Rif’at bin Muhammad Sabri and Periasamy
Karthigan s/o Selvam
School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus,
14300 Nibong Tebal, Pulau Pinang
Abstract. Despite the fact that preservative treatments prolong the life of wood, thus they can also accelerate the corrosion
of fasteners. This is a problem that needs to be studied because the corrosion of building materials and fasteners can harm
the system performance. In this study, an overall view of all the test methods previously used to measure the corrosion of
metals in contact with wood was studied, so that their effectiveness can be identified and compared. Although the focus is
on test methods, some qualitative results of these different methods are discussed to show the subtle differences in test
methods. In addition, this research review aims to direct future research to the most promising and more applicable
effective testing methods.
Keywords: corrosion, fasteners, wood preservative, corrosion rate, metals.
INTRODUCTION
Corrosion phenomenon occurs when a refined
metal is subjected to a chemical or electrochemical
reaction. An electrochemical reaction where a metal is
subjected to intense exposure to an oxidant produces
iron oxides, which are usually referred to as
"rusting"(Corrosion Basics: An Introduction, 1984).
Plus, there are many structural alloys that can be
subjected to air-based corrosion, but exposure to
certain substances can greatly affect the process. This
phenomenon is known as concentrated corrosion
(Jones D.A., 1996).
On the other hand, due to their high strength and
ductility, metals are used in a wide range of
applications. Metals, on the other hand, are
thermodynamically unstable in most environmental
conditions and corrode to a more stable (oxide) state.
While not generally regarded as an aggressive
environment, there is still the possibility of severely
corroding metal, particularly when preservative or fire
treatments are used. Almost all timber engineering
applications involve the interaction of wood with
metal. The structural integrity of the wood is subjected
to the presence of oxygen and water. This contributes
to the accelerated decay of the wood around the
fastener. (Bailey, G.,Schofield, M.J. 1984).
Waterborne preservatives such as copper arsenate and
ammoniacal copper arsenate have also been used to
treat bridge decks. While some of these chemicals
bond to the wood and become fixed, a small percentage
of them remains in ionic form.
Most metallic corrosion occurs when the metal and
the electrolyte solution are subjected to an
electrochemical reaction. An example of this is when a
film of moisture forms on a metal surface to form the
electrolyte for atmospheric and rod corrosion. (Barnes,
H.M., Nicholas, D.D., Landers, R.W. 1984)
An equilibrium between the anodic and cathodic
reactions can be maintained by the presence of both
reactions. In most cases, the anodic reaction produces a
spike in the flow of electrons, while the cathodic
reaction removes electrons. The potential of a metal is
the mechanism by which the anodic and the cathodic
reactions are maintained in balance. In other words, if
the metal has a high potential, the anodic reaction will
produce more current than the cathodic reaction.
The equilibrium potential of a metal is called Eoc. It
is assumed that the metal's open-circuit potential is
constant when no electrical connections are present. The
value of Icorr, which is the corrosion current, is often
referred to as the cathodic current. It can be used to
calculate the rate of metal. The concept of surface
corrosion is not very accurate since it doesn't take into
account the various stages of the metal's formation.
Instead, it focuses on the formation of an oxide layer on
the surface. Electrochemical techniques are ideal for
studying the corrosion processes due to their
dependence on the interaction of metals with water. In
these studies, a small metal sample is used to model a
corrosion process. The sample is then immersed in a
solution that is similar to the environment in which the
process occurs via the Electrochemical Impedance
Spectroscopy (EIS) method of analysis.
Both potentiostatic and galvanostatic polarization
are useful in the study of corrosion. The former
measures the current and the latter the potential. In both
cases, the polarization is done potentially and the
potential is measured. The former is used to study the
effects of Eoc on the sample while the latter is used to
model the behavior of the metal.
OBJECTIVE
The general aim of this study is to provide a holistic
view of a targeted test method applied for measuring the
corrosion of metals in contact with wood so that their
effectiveness can be compared. Furthermore, this study

3. review is intended to direct future research toward the
most promising and better applicable effective test
methods.
RESULTS
Figure 1: Nyquist plot of the metal
Table 1: Tabulate data on Nyquist plot from the
experiment on metal
The interpretation of the EIS measures is usually
done by the correlation between the impedance data and
the equivalent circuit representing the physical processes
taking place in the system under investigation or through
graphics. The graph Z = Z' + jZ'' real part and imaginary
part, respectively, measured at different frequencies is
called "Nyquist diagram", impedance diagram or
impedance spectrum. (Electrochemical Methods;
Fundamentals and Applications, 2000). The diameter of
the semicircle extrapolated in the Nyquist diagram
represents the charge transfer resistance Rt equivalent to
the polarization resistance Rp. Thus, the larger the
diameter of the semicircle the higher the resistance, Rp,
and hence, the lower the corrosion rate. If the polarization
resistance is higher, the corrosion resistance also
increases accordingly.
DISCUSSION
According to theory, we can know that corrosion
occurs because of a certain situation or characteristic, for
example the reactants, mainly water and oxygen, must
diffuse to the metal surface, and upon reaching the
surface, the reactants must have enough energy to
complete the reaction. Because these steps are in series,
the slower of these two steps dominates the rate of
corrosion. If there is an abundance of the reactants at the
surface, the reaction rate is controlled by the number of
atoms with enough energy to cross the energy barrier to
complete the reaction. Because the number of atoms with
this energy is a thermally activated process this situation
is said to be “activation controlled”. The bolt and nut
corrosion corrodes if all the oxide is removed from the
metal after corrosion has occurred, corrosion can be
measured by the mass loss per unit time. However, simple
mass loss measurements fail to describe the damage of the
corrosion because they are not normalized by the size of
the test specimen. The nails were driven in pre drilled holes
into the preservative-treated lumber. An interesting aspect
of Baker’s test setup was that the nails were driven through
two pieces of preservative-treated wood to simulate how
nails are used in service. The data collected on the different
alloys used can be used to get a relative ranking of alloy
performance in treated wood, assuming that the
mechanism of corrosion does not change significantly
between underground and aboveground exposure. At
higher moisture contents, wood conducts electricity and
ions better, and therefore, the corrosion reaction occurs at
a faster rate. Because the equilibrium moisture content of
wood is dependent on the temperature and the RH, the
effects of these two variables must be examined together.
The kinetics of corrosion (oxidation) are faster at higher
temperatures because diffusion and other processes of
corrosion are thermally activated. However, at higher
temperatures, there is less thermodynamic tendency for
corrosion (oxidation) to occur because it is an exothermic
reaction.
CONCLUSION
It can be concluded that corrosion may occur due to certain
conditions or characteristics, for example, the reactants
(mainly water and oxygen) must diffuse to the metal
surface, and when they reach the surface, the reactants
must have sufficient energy to complete the reaction.
According to studies, if all oxides are removed from the
metal after corrosion occurs, the bolts and nuts will
corrode. Therefore, the corrosion can be measured by the
mass loss per unit time. Furthermore, the higher the
moisture content, the better the conductivity and ionic
conductivity of the wood, and therefore, the faster the
corrosion reaction occurs. Moreover, at higher
temperatures, the kinetics of corrosion (oxidation) is
faster, because diffusion and other corrosion processes are
activated by heat. However, at higher temperatures, since
it is an exothermic reaction, the thermodynamic tendency
of corrosion (oxidation) is small.
ACKNOWLEDGMENTS
Above all, the greatest gratification to almighty God who
gave us the strength to complete this task just in time.
Secondly, the entire merit of our lecturer, Assoc. Prof. Dr.
Ahmad Azmin Mohamad for his hard work, who taught us
patience and his humble attitude, means a lot to us. Finally,
our group members who accept the challenge set by our
superior and the positive attitude is commendable and
commendable even if we encounter many difficulties to
complete it, thanks to our teamwork and diligence that we
manage to achieve the final outcome and successful
assigned task completion.

4. REFERENCES
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Fundamentals and Applications, A.J. Bard. Wiley
Interscience Publications 2000.
2. Jones, D.A. (1996) Principles and Prevention of
Corrosion, 2nd Edition, Prentice Hall, Upper
Saddle River, NJ.
3. Corrosion Basics: An Introduction (1984).
National Association of Corrosion Engineers,
Houston.
4. Electrochemical Estimation of the Corrosion Rate
of Magnesium/Aluminium Alloys. Retrieved from
https://doi.org/10.1155/2010/953850