In in the outer shell is very

In the above picture we can see the Periodic Table, the
periodic table is known to be the alphabet of the universe by the scientist.
They are classified in to 18 groups and 7 rows; elements of the same
group/family have same properties for example in group 9, Cobalt and Iridium
has same properties; same with group 1, Lithium and Potassium has same
properties apart from Hydrogen which is very special and has its own properties
regardless its group. In other word, we can say Hydrogen has its own group. The
number of rows represents the number of Orbit/Shell the element has, and each
shell is filled with electron with 2 electrons in the first shell, 8 elections
in the 2nd and 3rd and 18 on the rest. The number of electrons are always equal
to the number of the protons in the nucleus and the numbers of electron in the
outer shell is very important to decide the properties of the elements.

If the outer shell has enough room for an outer electron to shar the
orbit it will shar forming a covalent bond or maybe take an outer electron
completely without sharing which is known as ionic bond. For example, when a
metal atom reacts with non-metal atom where the outer election from metal
elements transfers to non-metal atoms this is known by ionic bonding, i.e.
Lithium and fluorine where the Lithium loss one of its electron to Florine as
shown on the picture on the right. When non-metal atom bond together it is
known by covalent bonding, i.e. 2 Hydrogen bonds together to form covalent bond
as shown on the picture on the right, for both bonding now that they have full
outer shell electron they are not reactive what so ever. Some elements such as
Neon for example has full outer shell with 8 electrons in the second shell, it
has no room to give or take any electron there for it is very inactive/sleeping
elements, they are also known by noble gas. When talking about degradations of material either
metal or non-metal we are talking about the failed of the material or extreme
reduction in their life cycle. Metals and Non-metals have different factors
that affects themes, and this is due to its properties resulted is atomic
structure. Metals: The metals are
very famous of rusting or corroding. When Oxygen, Water, and electrolyte exist
rusting take place and normally salt acts as electrolyte solution which helps
the electrons to follow; also, oxidation where the metals start reacting with
oxygen during corrosion. An example of rusting and corrosion can be seen in the
picture below where the engine in the boat is rusted and the pipe corroded and

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Non-Metals: Plastics and
woods are classed as non-metals, they do not conduct heat or electricity, nor
do they rust or corrode like metals. However, there are other factors that can
cause the failed of wood and plastic such as the ultra violet and high
temperature weakening the plastic or even melting them, an example from daily
life is a plastic chaired is left in the garden under sun light for lengthy
time they can be vary brittle and very weak and dry and break easily example
picture shown below. Same goes for wood where they get defected by fungi (decay
or rot), insects and weathering. For example, when the insects attack the
furniture they end up getting holes which as a result weaken the foundation
making the whole body un-stable. Example pictures are shown below. Three types of common degradations that occur in metals
are Oxidation, Electrolytic Corrosion and Sulphuric Attack. Oxidation: If any metal or non-metal reacts
with oxygen they are called oxidation, and corrosion due to oxidation is a
common degradation that we must deal with quit often, for oxidation to take
place we need water/moister and oxygen, the electrons from the metals transfer
to the oxygen as a result, positively charged melic ions and negatively charged
oxygen ions is formed. These two negatively charged ions forms an oxide layer
on top of the metals known as rust or corrosion. The process of oxidation can
be increased in the presence of high temperature and sodium chloride table

Electrolytic Corrosion: Theses are
also know by galvanic corrosion, if we look in the table on the right we can
see the most active to least active metals, when placed together the one will
act as anode and other as cathode and the most reactive one if placed with
least reactive one from the table the most reactive on will start to corrode,
For example, if an aluminium box which is secured with iron screws are placed
near sea, the aluminium will corrode and the iron nail with fall apart this is
because the aluminium got corroded and failed, and this happened because
electrons from aluminium went to iron. For the electrolytic corrosion to take
place we need water but in a dry space the electrolytic corrosion can still
take place and this because any material around us has a very thin layer of
water which means it will be super slow corrosion which increased when moved
near sea.

Attack:Oxidation: There are three common different ways in
which we can prevent oxidation such as:  ü Painting: This involves painting the parts
where exposed to oxygen and moister and we can see this in our everyday life
such in cars and bicycles.ü Oil &
Grease: Adding grease or oil reduce the corrosion a lot such as in bicycles
where the grease is added in its chain which lubricates it and reduce the friction
that can expose the metals to air and cause oxidation. ü Galvanising: This is also known by a
sacrificing method and this is because one metal sacrifice for the other. From
the reactivity table we can know that Zinc is more reactive than Iron; therefore,
if we take the both and expose it to oxygen and moister, zinc will corrode
faster than iron as a result zinc gets rusted and sacrifices its self for the
iron and this method is used Widley on chips to prevent rusting and the rust
from the zinc can be removed and used again for further protection. Electrolytic Corrosion: There are
three methods where we can stop electrolytic corrosion and they are as
following: ü
Coating: we place a coating such as
paint. In other word painting. ü
Insulation: This involve adding
insulating layer between anode and cathode, so the electrons cannot pass
between them. ü
Galvanic Material: Selecting the galvanic
material wisely from the table with potential activity difference less than 0.2

Sulphuric Attack:  



High Carbon Steel

Mild Steel


•           Melting Point: 1800°C
•           Harder than mild steel
•           Very brittle,
•           Can be heat-treated to make it
harder and tougher
•           Ferro’s Metal

•           Melting point: 1600°C
•           Tough
•           Ductile
•           Malleable
•           Good tensile strength
•           Poor resistance to corrosion
•           Ferro’s Metal

Over all Properties

general metal are in solid state, they are hard, shiny and good conductor of
heat and electricity. They also have high melting point with high density
which mean expect them to be heavy. The similarity between the two mention
metals that they both have very high melting point and are very hard, yet the
high carbon steel is very brittle, and this is because of high carbon content
and this can be improved with heat treatment. They both are ferrous metal
which means mean they both contain iron on them.







•           Melting point 44°C
•           Boiling Point 280°C
•           The are dull and make dull sound
when you hit them.
•           Poor conductor of heat and
•           Brittle

•           Melting point 113°C
•           Boiling point 445°C
•           Insoluble in water
•           Poor conductor of heat and
•           Odourless

Over all Properties

of the Non-metals are gases apart from one which is liquid, and the rest are
solids. In general non-metals are dull with full electrons on their outer
orbit, they also least conductor of heat and electricity. They have very low
melting point compared to metals.

 Non-Destructive Test:
These are the test that involve not destroying the test sample. 1.     
Ultra-Sonic Test: The Ultra-Sonic test is
non-destructive test that uses sound and its reflection (eco) to locate cracks
in a sample. The defects can be studied using intensity/time graph as shown in
the picture below.

As can be seen
the probe will send and receive the sound impulses and this will create the
curves, in the graph above we can see two curves; one is when the sound is
transmitted and the other one is when the sound is reflected. In the picture
below, we can see how the graph will look like when the sound hits the defected
point. In the above
picture we can see how the curve will look like when the sound hits a defect
and bounce, it creates an abnormal wave which show a defect. And this is how we
can know if the work same got any defects without damaging the sample. When
using this in the computer system we can replace the Time with depth and by
that we can know at what level is the defect is, generally the ultra-sonic
testing is even better than magnetic testing but can coast more. 2.     
Radioactive Testing: This is
another common non- destructive testing which uses gamma or X-Rays, this test
can be a bit costly but a good detector for porosity, inclusions and cracks.
The inspected area is measured and marked with a mounted film and the radioactive
current, voltage and duration is adjusted depending on the type and thickness
of the material. The x-ray goes through the sample material and generate a
radioactive image on the film also known as imaging plate once processed, then
finally an engineer inspects the image to find the quality of the sample and if
there are any defects. The picture below shows an example of radioactive image.   

 In the picture
above the black area is the area which is not exposed to radioactive rays, the
lighter part is the one which had little exposure to the radioactive rays, the
rest we can see a dark white which had great exposure to the radioactive rays
and we can see the defective marks easily on the picture.  3.      Dye Penetrant
Inspection: This is another very famous non-destructive testing to
expose the defects on a sample material, the down side about this testing is
that it can be a bit messy, this type of test is very cheap and can be carried
out at home. The material sample is cleaned perfectly so if there are any
defects it can be exposed to the surface. The penetrant is added to the sample
which sinks in to defects if there is any. The sample is than allowed to dry
for couple of mints than rinsed with water, after that a developer is added to
the sample, the developer is normally a fine grained white powder suspended in
liquid, once its dried the penetrate starts coming out of the crack, by that
the defects are easily detected. 

          In the picture above, we can see how the cracks are exposed in red.     Useful Results: ü
Immediate Results ü
Internal defects can be detected ü
Detects even the extremely small defects ü
Can detect the nature of defects such as size, length and
High penetrating power which will detect deep in to the
sample.   Reference: 1.     
Ultrasonic Testing, MaterialsScience2000,
Published on 12 Mar 2014, Prof. Dr.-Ing. Rainer Schwab, Hochschule Karlsruhe
(Karlsruhe University of Applied Sciences), Germany.     
Ultrasonic Testing of Welds, March,23,2014, USA.     
Applus RTD NDT Radiographic Testing,
ApplusRTD, Published on 5 Nov 2014,     
Penetrant Inspection, MaterialsScience2000, Published on 4 Mar 2014, Prof.
Dr.-Ing. Rainer Schwab, Hochschule Karlsruhe (Karlsruhe University of Applied
Sciences), Germany.                    Destructive Test: This
test involves testing the material until the frailer of the sample. The tensile
test is one of the destructive test. 


In the picture above, we see the difference between High carbon steel and
Mild steel.       Useful Results: There are many results can be
extracted from this test such as: ü
Strength of the material ü
Hardness of the materialü
Ultimate Strength point

Modulus of elasticity 


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