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Effect Of Environment On Corrosion

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Corrosion, a process influenced by various environmental factors, refers to the deterioration of materials, often metals, due to chemical reactions with their surroundings. The impact of the environment on corrosion is substantial, with climatic conditions and exposure playing pivotal roles. Harsh weather conditions, such as high humidity and coastal proximity, accelerate the corrosion rate by facilitating the formation of corrosive agents like salt and moisture on metal surfaces. Additionally, industrial pollutants and atmospheric gases contribute to the corrosive environment, further exacerbating the degradation of materials. Understanding the intricate interplay between environmental elements and corrosion is essential for developing effective preventive measures and materials with enhanced resistance, mitigating the detrimental effects of exposure and promoting the longevity of structures and equipment in diverse settings.

ABSTRACT

In this research project, the various nail were subjected to six environments so as to check the effect of the environments on corrosion of the nails.
Two sets of nails were used; normal nail and concrete nail. Six of each type while the other not coated.
The research was carried out in the physical chemical laboratory of the institute of management and technology.
The environments used are acidic solution, alkaline solution, salt solution, boiled water, air medium and lubricating oil medium, which served as a control medium.
It was observed from the graphs of the weight of metal against time, that acidic environment gave rise to corrosion at a faster rate that other environment. It was also observed that normal nails gave rise to corrosion at a faster rate than concrete nail.
Coating of metals was also concluded to be a method of preventing the rate of corrosion of metals even though it does not stop corrosion.

TABLE OF CONTENT

Title page
Approval page
Letter of transmittal
Dedication
Acknowledgement
Abstract
Table of content

CHAPTER ONE
INTRODUCTION
1.1 Objectives of the Study
1.2 Scope of the Study
1.3.1 Significance Of The Research

CHAPTER TWO
LITERATURE REVIEW
Historical Background
2.1 Theory of Corrosion
2.1.1 The Corrosion Process
2.1.2 Energ for the Corrosion Process
2.2 Forms Of Corrosion
2.3 Factor Affecting Corrosion Rate
2.3.1 Physical Factors Influencing Corrosion
a surface condition.
2.3.2 Environmental Factors
2.4 Corrosion Inhibitors
2.4 Electro Chemical Effects Of Corrosion
2.6 Starry Currents
2.7 Corrosion Testing Methods
2.8 Corrosion Monitoring Methods
2.8.1 Coupon Method
2.8.2 Probe Method
2.8.3 Liquid Analysis Method
2.8.4 Corrosion Products Analysis
2.8.5 Gas Analysis
2.9 Protective Coatings

CHAPTER THREE
3.0 Experimental Method
3.1 Materials/ Instrument and Tools Used
3.2 Procedure

CHAPTER FOUR
EXPERIMENTAL RESULT/OBSERVATIONS

CHAPTER FIVE
DISCUSSION

CHAPTER SIX
CONCLUSION

CHAPTER SEVEN
Recommendation
References

CHAPTER ONE

INTRODUCTION
In its broadest sense the term corrosion applied to the destructive alteration of a metal or alloy by chemical reaction with any substance, solid, liquid, or gas. The pattern of attack will be governed largely by the combined influence of several factors relating to the metal or alloy, to the conditions of service, and to the chemical nature of the environment.
1. The metal may corrode uniformly over its entire surface, as in the resting of iron in the atmosphere.
2. It may suffer only a superficial attack that does not seriously affect the strength of the metal or alloy but does discolour the surface, as in the tarnishing of silver in the atmosphere.
3. Corrosion may develop at local areas on an otherwise unattached surface, leading to pitting that may in some instances result in early failure by perforation.
4. An alloy may be attacked in such a way as to remove one or more of its constituents, leaving a weakened residue of unattached element with poor metallic properties, as in the dezincification of yellow brass or in the graphitization of cast iron.
5. Excessive corrosion may occur in local area where poor design features tend to aggravate the corrosion conditions, as crevices under rivets, bolts and faying surface.
6. Use of dissimilar metals sometimes can lead to severe attack of the more active metal where they are joined together.
7. High tensile stresses plus specific corrosive conditions may result in cracking of a metal because of a corrosion reaction along critical paths in the metal.
In order to provide a quantitative basis for reporting corrosion rates and intensity of attack, the average weight loss of metal per unit area per unit time or the loss in thickness per unit time is usually recorded. Loss in thickness per unit time is more useful in those instances where the engineer is concerned with life of equipment or structure. Average loss is reported in mils per year (MPY) or inches penetration per year (ipy). Where product contamination is vital, the average corrosion rate is expressed in milligrams of metal corroded per square decimeter per day (mdd).
Corrosion process usually occurs because the metal has a tendency to return to its native state, the form in which it is found in nature. This require that the metal atoms relinquish their valence electrons to the environment and because ions in the process. The newly formed ions may then combine with other ions to from compounds. This, when iron corrodes in water, the iron atoms are converted to ferrous ion upon the loss of two electrons.
Fe Fe2++2e-
The ferrous can then combine with hydroxyl ions to from insoluble ferrous hydroxide.
Fe Fe2++20H Fe(0H)
This compound eventually becomes oxidized through content with oxygen the familiar red iron rust, ferric hydroxide. In the electrons from the iron are accepted by oxygen gas molecules and iron oxides are formed.

1.1 OBJECTIVES OF THE STUDY
The objective of this study in based on the fault that corrosion which has been a major problem in our modern industries has to be prevented and curbed to the barest minimum by putting it environment into consideration in selecting material a structure or piece equipment.

1.2 SCOPE OF THE STUDY
The main metallic material that is being used in this work is nail (iron). This material will be subjected to different medium (environment) viz air medium salt solution medium, distilled water medium acid solution medium, alkaline solution medium and a lubricating oil medium. The observable change brought about by the environment reaction to the material under survey was studied. Iron of varied coatings will also be used.

1.3.2 SIGNIFICANCE OF THE RESEARCH
A complete understanding of corrosion phenomena in all fact requires intensive and prolonged study. However, a general knowledge of the subject can be gained by the engineer through a review or survey of the various ways in which corrosion manifest itself, the factors that govern corrosion process, and the means available to the engineer for controlling or preventing corrosion.
This work will provide a survey that will serve to guide the material engineer his consideration of corrosion behaviour of metals and alloys virus, it will enable those in the oil and gas sector to install pipelines in an environment that will be favourable.

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Effect Of Environment On Corrosion:

The environment plays a significant role in the corrosion of materials, especially metals. Corrosion is the process by which materials, particularly metals, deteriorate due to chemical reactions with their surroundings. Different environmental factors can accelerate or decelerate corrosion processes. Some of the key environmental factors that affect corrosion include:

Moisture/Humidity: The presence of moisture, in the form of water or humidity, is a primary factor in corrosion. Moisture allows the electrochemical reactions necessary for corrosion to occur. In humid or wet environments, metals are more susceptible to corrosion.

Temperature: Temperature can influence the rate of corrosion. Generally, higher temperatures accelerate corrosion reactions, while lower temperatures slow them down. Extreme temperature fluctuations can also lead to thermal cycling corrosion.

Atmosphere: The composition of the surrounding atmosphere can significantly impact corrosion. For instance:
Oxygen: Oxygen is often necessary for the corrosion of metals, especially in the case of iron, which rusts in the presence of oxygen and moisture.
Sulfur compounds: Presence of sulfur-containing compounds in the atmosphere, such as sulfur dioxide (SO2) or hydrogen sulfide (H2S), can lead to forms of corrosion like sulfide stress cracking or hydrogen embrittlement.
Salinity: In coastal or marine environments, the high salt content in the air can accelerate corrosion due to the corrosive nature of salt (chlorides).

Chemical Pollution: Exposure to industrial pollutants, gases, or chemicals can enhance corrosion. Acidic gases like sulfur dioxide and chlorine, for example, can react with metals and accelerate corrosion processes.

pH Levels: The acidity or alkalinity of the environment (pH) can impact corrosion rates. Highly acidic or alkaline conditions can be corrosive to certain metals.

Microbiologically Influenced Corrosion (MIC): Microorganisms like bacteria, fungi, and algae can colonize the surface of metals and promote corrosion through the production of corrosive byproducts.

Mechanical Stress: Mechanical stress, such as vibration, can accelerate the onset of corrosion by removing protective surface layers on metals.

UV Radiation: Ultraviolet (UV) radiation from the sun can affect the protective oxide layers on some metals, making them more susceptible to corrosion.

Coating and Protection: Protective coatings, such as paints, platings, or corrosion inhibitors, can shield metals from the surrounding environment and slow down the corrosion process.

Galvanic Corrosion: When dissimilar metals are in contact in an electrolyte (e.g., saltwater), galvanic corrosion can occur due to the difference in their electrochemical potentials.

It’s important to note that the combination of these environmental factors can result in various forms of corrosion, such as general corrosion, pitting corrosion, crevice corrosion, galvanic corrosion, and stress corrosion cracking, among others. Understanding the specific environmental conditions and their effects on materials is crucial for designing effective corrosion prevention and mitigation strategies.