internship report PCSIR

Final Report
 Submitted by: Muhammad Salman Arif
 Institution: National University of Science &
Technology, Islamabad
 Work place: PIETMAEM, PCSIR
 Submission Date: July 16,2015

July 14, 2015 Pakistan Council of Scientific and Industrial Research
School of Chemical & Material Engineering, NUST, Islamabad 1
Contents:
1. Metallography Pg# 5-9
1.1. Introduction
1.2. Steps
1.2.1. Sectioning
1.2.2. Mounting
1.2.2.1. Cold mounting
1.2.2.2. Hot mounting
1.2.3. Grinding
1.2.4. Polishing
1.2.5. Etching
1.2.6. Microscopy
1.3. On site metallography
1.4. Macro etching tests
1.4.1. Welding fusion
1.4.2. Seamless test
1.4.3. Forging test
1.5. Coating thickness
2. Mechanical testing Pg#10-18
2.1. Introduction
2.2. Tensile test
2.2.1. Process
2.3. Bend test
2.3.1. Calculation of span
2.3.1.1. Steps
2.3.1.2. Formula
2.3.1.3. Discarding of sample
2.3.1.4. ASTM standard

2.4. Compression test
2.4.1. Experiment
2.5. Impact test
2.5.1. Calculations
2.5.2. Factors effecting impact test
2.6. ASTM standards
2.7. Grips
2.7.1. Round
2.7.2. Flat
2.7.3. Rope
3. Powder metallurgy & Foundry Pg#19-22
3.1. Introduction
3.2. Steps
3.3. Procedure
3.4. Properties & Advantages
3.5. Foundry Shop
3.5.1. Steps
3.5.1.1. Preparation of moulds
3.5.1.2. Melting
3.5.1.3. Pouring
3.5.1.4. Breaking of mould
3.5.1.5. Finishing
4. Non-Destructive Lab Pg#23-31
4.1. Introduction
4.2. NDT’s
4.2.1. MT
4.2.2. PT
4.2.3. RT
4.2.4. UT
4.2.5. Eddy Current
4.3. Hardness tests Pg#32-35
4.3.1. Vicker’s test

4.3.2. Rockwell hardness test
4.3.2.1. Rockwell hardness scale
4.3.2.2. Application of scales
4.3.2.3. Rockwell superficial scale
4.3.3. Brinell’s hardness test
4.3.4. Shore hardness test
4.3.5. IRHD
4.3.6. Portable hardness tester
5. Optical emission spectroscope Pg#32-35
5.1. Principle
5.2. Specification
5.3. Analysis
5.4. ASTM standards
5.5. Calibration
6. Bio-materials Pg#36-39
6.1. Introduction
6.2. CS-Determinator
6.2.1. Particulars
6.2.2. How heat is accomplished
6.3. Potentiostat
7. Jewelry & Hallmarking Pg#40-46
7.1. Introduction
7.2. Apparatus
7.2.1. XRF
7.2.1.1. Underling physics
7.2.1.2. Characteristics radiation
7.2.1.3. Primary radiation
7.2.1.4. Detection
7.2.1.5. X-ray intensity
7.2.1.6. Chemical analysis
7.2.2. Densitometer
7.2.2.1. Introduction

7.2.2.2. Working principle
7.2.3. Hall marking
7.2.3.1. Apparatus
7.2.3.2. Purity of gold
7.3. ASTM standard
8. Physical vapor Deposition Pg#47-51
8.1. Introduction
8.2. Sputtering
8.3. Advantages
8.4. Applications
8.5. Apparatus required
8.6. Coating types
8.7. Coating thickness
9. Scanning Electron Microscope Pg#52-55
9.1. Introduction
9.2. Specification
9.3. Advantages
10. References Pg#56
11. Acknowledgements Pg#56

Lab 1
Metallography
Instructor: ____________
____________

Introduction:
The microscopic study of the structure of metals and is called metallography.
Metallography is the process of preparing a sample of material by polishing and
etching so that the structure can be examined using a microscope. The range of
magnification of an optical microscope makes it suitable for grain structure
examination and grain size estimation.
Steps:
Following steps are carried out during metallography:
 Sectioning
 Mounting
 Grinding
 Polishing
 Etching
 Microscopy
Sectioning:
This is an optional step in metallography in which the proper size of the sample
for the further steps is prepared. We cannot observe the whole object, so we
take a representative out of it with the help of cutting. Care must be taken to
ensure that it is representative of the features found in the larger sample.
Cutting can be done:
 Electrically by diamond cutter.
 Mechanically by hacksaw.
We ensure continuous flow of water during cutting to avoid any burn.
Mounting:
This is also an optional step for the ease of handling the sample. This provide us
easy grip and avoid bulging of the sample. There are two types of mounting:
 Hot mounting
In hot-mounting the sample is surrounded by an organic polymeric powder
which melts under the influence of heat (about 200 oC). Pressure is also

applied by a piston, ensuring a high quality mould free of porosityand with
intimate contactbetween the sample and the polymer.
 Cold mounting
Mounting can be done cold using two components which are liquid to start
with but which set solid shortly after mixing. Cold mounting techniques
offer particular advantages when a specimen may be too delicate to
withstand the pressures and heat involved in compressionmolding. The
three most common types of materials are Epi-oxides, Polyesters, and
Acrylics
Cold molding hot molding
Grinding:
It is done to make sample smooth, scratch less and to remove bulging if any.
This can be done automatically using a grinding wheel or manually using emery
paper. The grinding wheel consists of a disc covered with silicon carbide paper.
Water is applied continuously to wash out the sample. There are a number of
grades of paper i.e. 180, 400, 600, 800, 1000, 1500 and 2000 grains of silicon
carbide per square inch. 180 grades therefore represent the coarsest particles
and this is the grade to begin the grinding operation.
Polishing:
Polishing is the final step in production a surface that is flat, scratch free, and
mirror like in appearance. This can be done by diamond paste or alumina
powder. Diamond paste is used for rougher surface (1-10 micron) while
alumina powder is used for smother surface (less than 1 micron). The polishers

consist of rotating discs covered with soft cloth made of velvet or nylon
impregnated with diamond particles (6 and 1 micron size) and an oily
lubricant. Begin with the 6 micron grade and continue polishing until the
grinding scratches have been removed. It is of vital importance that the sample
is thoroughly cleaned using soapy water, followed by alcohol, and dried before
moving onto the final 1 micron stage. Any contamination of the 1 micron
polishing disc will make it impossible to achieve a satisfactory polish.
Etching:
After polishing the specimen is allowed to dry. This can be speed up by using a
hot air drier. Etching is then used to reveal the microstructure of the metal.
Basically etching is a chemical attack. The etchant attacks high energy sites
such as grain boundaries also etchant preferentially attacks specific
crystallographic orientations hence a contrasting pattern is formed on the
surface of the specimen between grains. In alloys with different phases etching
creates contrast between different regions through differences in topography or
the reflectivity of the different phases. All this contrast creates a surface finish
which allows the grain boundaries, phases, precipitates and different crystal
orientations to be easily distinguished.
The specimen is etched using a reagent. This is applied using a cotton bud
wiped over the surface a few of times. The specimen should then immediately
be washed in alcohol and dried. Care should be taken to avoid over-etching a
sample. During etching some localized chemical attack results in formation of
pits which usually don’t really obscure the real features of microstructure but
in case of over etching these pits can grow and hide the real features of the
microstructure.
Usually for steel family we use Nital solution (2%nitric acid + 98% Alcohol)
Cu related alloys uses HF solution as etchant. While electrolyzing
etching can also be used as a speedy phenomenon having electrolyte of 10%
Oxalic acid
The surface to be examined should be flat and level otherwise if viewing area
is moved across the surface it will go out of focus also whole of the field of
view will not be in focus i.e. only the center will be in focus the sides won’t be.
To rectify this, a simple process can be used. The mounted specimen is placed
on plasticene on a microscope slide and the specimen leveling press presses the

mounted specimen into the plasticene making it level. A small paper or cloth is
placed over the specimen to avoid scratching.
On site metallography:
The type of metallography used for heavy industrial object or the instruments
under operation carried out on the site is called on site metallography. This is also
known as replica testing. It has same procedure to that of the laboratory
metallography while at the end the image is copied on the rubber like material and
studied later on the microscope.
Macro Etching tests:
Following tests can be done on macro level:
 Welding fusion
we check voids, corrosion in this process.Sample is grinded from both ends
and is swabbed in the aqua regia welding defects appears.
 Seamless test
this test is carried in the above similar way.
 Forging test
in this test the sample is boiled in 50% HCl solution with water. If the
sample is forged than lamellar lines appear at macro level.
Coating Thickness:
For this we need a cross-sectionalanalysis of the specimen. The specimen is then
mounted and put under an optical microscope. The thin layer of coating is adjacent
to the base metal. The left eye piece has a scale consisting of two perpendicular
bisecting lines divided into equal intervals. The number of intervals is counted and
divided by the magnification to give the coating thickness in millimeters.

Lab 2
Mechanical testing
____________

Introduction:
This lab is a set of destructive tests. This allows us to test the strength of the
materials by different tests. Following tests were done:
 Tensile test
 Compressiontest
 Bend test
 Impact test
Tensile test:
The specimen gauge length is marked according to ASTM standards. The
specimen is placed in the machine between the grips and an extensometer if
required can automatically record the change in gauge length during the test. If an
extensometer is not fitted, the machine itself can record the displacement between
its cross heads on which the specimen is held. However, this method not only
records the change in length of the specimen but also all other extending elastic
components of the testing machine and its drive systems including any slipping of
the specimen in the grips. Tensile test is used to measure yield point, maximum
load and % elongation.
Process
The test process involves placing the test specimen in the testing machine and
applying tension to it until it fractures. During the application of tension, the
elongation of the gauge section is recorded against the applied force. The data is
manipulated so that it is not specific to the geometry of the test sample. The

elongation measurement is used to calculate the engineering strain, ε, using the
following equation:
Where ΔL is the change in gauge length, L0 is the initial gauge length, and L is the
final length. The force measurement is used to calculate the engineering stress, σ,
using the following equation:
Where F is the force and A is the cross-sectionof the gauge section. The machine
does these calculations as the force increases, so that the data points can be
graphed into a stress-strain curve. But the machine here plots data into force-time
curve.
Table 1 Data used for calculations in Tensile Testing
Sample ID Weight (g) Length
(mm)
Weight/Length
(g/mm)
Area
(mm2)
Diameter
(mm)
1 468 450 1.04 132.48 13.00
2 460 450 1.02 130.21 12.87
After the calculation of diameter, a gage length of 200 mm was marked on it and
then it was fitted in the grips of UTM such that the gage length lies in between the
grips. After the completion of test the result were as follows
UTS = (90.58 KN/130.21 mm2) = 7 x 108 N/m2 = 700 MPa
Upper yield point = 71.65 KN = 550 MPa
Lower yield point = 70.94 KN =544 MPa
%𝑎𝑔𝑒𝑒𝑙𝑜𝑛𝑔𝑎𝑡𝑖𝑜𝑛 =
222−200
200
× 100 = 11%

BEND TEST
Bending tests are carried out to
ensure that a metal has sufficient
ductility to stand bending without
fracturing. A standard specimen is
bent through a specified arc and in
the case of strip, the direction of
grain flow is noted and whether the
bend is with or across the grain. In
engineering mechanics, bending
(also known as flexure)
characterizes the behavior of a
slender structural element subjected to an external load applied perpendicular to an
axis of the element. When the length is considerably larger than the width and the
thickness, the element is called a beam.
Calculation of span (distance between the rollers)
Steps
 1-The thickness of sample should be measured.
 2-The thickness of the sample is taken twice of its actual thickness.
 3-Then Pin diameter in mm should be calculated.
 4-A factor of 15 is also used in the calculation well known as a safety factor.
 5-The doubled thickness of the sample with the diameter of the pin and a
safety factor are added to get the approximate distance between the two
rollers or span.
Formula
Span length=2T+Pin Dia+15
T=thickness of sample
Discarding of a sample:-
The sample would be discarded if there are cracks when it is bent. Moreover even
if there appears a crack of even 3mm, then the sample would be discarded.

ASTM Standards used for the bend test
 A370 ASTM
 ASTM E290
 ISO 7438
Compression Test:
Compressive strength is the capacity of a material or structure to withstand axially
directed pushing forces. When the limit of compressive strength is reached,
materials are crushed. Concrete can be made to have high compressive strength,
e.g. many concrete structures have compressive strengths in excess of 50 MPa,
whereas a material such as soft sandstone may have a compressive strength as low
as 5 or 10 MPa.
Compressive strength is often measured on a universal testing machine; these
range from very small table top systems to ones with over 53 MN capacity.
Measurements of compressive strength are affected by the specific test method and
conditions of measurement. Compressive strengths are usually reported in
relationship to a specific technical standard.
.
Experiment:
1. First fix the assembly, the equipment’s and parts of the machine in UTM.
2. Then for safety purpose check all the things working correctly or not.
3. Now place the sample in the UTM.
4. Start the test from the computer and wait for the fracture.
5. When the Fracture occurs note down the readings.
IMPACT TEST
The Charpy impact test, also known as the Charpy v-notch test, is a standardized
high strain-rate test which determines the amount of energy absorbed by a material
during fracture. This absorbed energy is a measure of a given
material's toughness and acts as a tool to study temperature-dependent ductile-

brittle transition. It is widely applied in industry, since it is easy to prepare and
conduct and results can be obtained quickly and cheaply. A major disadvantage is
that all results are only comparative.
The standard Charpy-V specimen (illustrated in Fig.1) is 55mm long, 10mm
square and has a 2mm deep notch with a tip radius of 0.25mm machined on one
face.
Fig.1. Standard Charpy-V notch specimen
To carry out the test the standard specimen is supported at its two ends on an anvil
and struck on the opposite face to the notch by a pendulum. The specimen is
fractured and the pendulum swings through, the height of the swing being a
measure of the amount of energy absorbed in fracturing the specimen.
Conventionally three specimens are tested at any one temperature; and the results
averaged.
Calculations:
Length of the Hammer = R = 0.75m
Weight of the Hammer = W = mg = 26 Kg × 9.8 m/s2 = 235.2 N
Angle of fall = α = 1450

Temperature
of the
specimen ℃
Angle
of rise
Energy
absorbed
by
specimen
(Nm)
Energy
absorbed
by the
specimen
in (ft-lb)
Case 1 -5 114.5 71.34 515.7
Case 2 -10 132 26.46 191.21
Case 3 -20 140 9.37 67.74
As temperature is decreased fracture tends to be brittle and less energy is
absorbed in it.
Factors Affecting Charpy Impact Energy
Factors that affect the Charpy impact energy of a specimen will include:
 Yield strength and ductility
 Notches
 Temperature and strain rate
 Fracture mechanism

Standards:
Following ASTM standards are followed in this lab:
A-370
 It is a more generalized standard which covers a wide area of
experiments
 It is used for steel and cast iron products
 For tensile test
 For bend test
 Charpy impact test
 Hardness test and many others
E-8/8M:
Used for tensile test of round bars of steel productlike deform bar, tor bar and
simple bar.
E-23:
It gives details of test methods and conditions under which the test is carried
out for charpy impact test
D-638:
Test methods for plastics are different than those from the steel. This standard
is for tensile test for plastic products
D-412:
Tensile test for rubber products
C-39:
For compressiontest of concretecylinders
C-140:
This standard is specifically for compressiontest of concrete cubes
C-67:
For compressiontest of bricks

A-615:
It gives specialization for test e.g. diameter, length, gage length, etc
Ultimate testing Grips:
A universal testing machine is used to test the tensile stress and compressive
strength of materials and also bend type test is performed. The sample is gripped
by following methods in this machine:
Round grips:
Round grips used for bars.
 12-35 mm
 35-60 mm
Flat grips:
Flat grips used for rectangular sheets.
 0-30 mm
 30-55 mm
Rope grip:
Ropegrips used for rope & wires.
 8-10mm
 16-22 mm

Lab 3
Powder metallurgy and Foundry
____________

Introduction:
the process of blending fine powdered materials, pressing them into a desired
shape or form (compacting), and then heating the compressed material in a
controlled atmosphere to bond the material (sintering)
Steps:
 Powder manufacturing
 Powder blending
 Compacting
 Sintering
Procedure
 The metal is taken in powder from. Particle size must be uniform.
 Binder is added to the powder in a fixed ration and the mixture is mixed
properly.
 The mixture is transferred into the die of the required shape.
 Pressure is applied on the die with the help of hydraulic press. Pressure
varies with the metal. Usually it is kept around 2000-10000 psi. This creates
mechanical bonds among the particles so it retains it shape.
 The compacted metal is then placed in furnace for sintering. Sintering
temperature is the three fourth of the melting point of the metal. Sintering
provide additional strength to the product. In this way the technique is quite
better than other techniques.
Properties and advantages
 High surface finish
 High density product
 High dimensional strength and accuracy
 Intricate and small shapes could be produced
 Cheap and time saving

Foundry shop:
Foundry is a workshop containing various machines and facilities of metal
fabrication including casting and fabrication tools. The basic process includes the
casting of metal starting from preparation of mold to the final machining
Steps:
Following steps are being carried:
 Preparation of mold
Mold is prepared by molding sand which contains
some kind of binder. Usually silica sand and molasses
(binder) are used due to being cheap and easily
available
 Melting
Metal to be casted is placed in the crucible. Crucible is
then placed in a furnace. To decrease the melting point
of the metal and for efficient slugging, flux is added to
the metal during the process which is called Fluxing.
After the metal melts, crucible is taken out of the
furnace and slag is skimmed off.
 Pouring
After melting the melt is poured into the mold and left for solidification.
Grain size is directly related to the rate of solidification. Higher the cooling
rate, smaller will be the grain size.
 Breaking the mold
The mold is then broken down to extract the casted piece. The metal casted
in foundry was aluminum.
Prepared Mold
Crucible placed in furnace

 Finishing
Finally the productis finished through cutting, hammering, grinding,
polishing and machining.

Lab 4
Non Destructive testing
____________

Introduction:
Non destructive tests along with hardness tests were performed in this lab. The
brief explanation of these experiments is given below.
NDT’s:
MT - Magnetic Particle Testing
Magnetic particle testing is accomplished by inducing a magnetic field in a
ferromagnetic material and then dusting the surface with iron particles. The
surface will produce magnetic poles and distort the magnetic field in such a
way that the iron particles are attracted and concentrated making defects on
the surface of the material visible.
PT - Dye Penetrant Testing
The dye penetrant testing can be used to locate discontinuities on material
surfaces. A highly penetrating dye on the surface will enter discontinuities
after a sufficient penetration time, and after removing the excess dye with a
developing agent, the defects on the surface will be visible.
RT - Radiographic Testing
Radiographic testing can be used to detect internal defects in castings, welds
or forgings by exposure the construction to x-ray or gamma ray radiation.
Defects are detected by differences in radiation absorption in the material as
seen on a shadow graph displayed on photographic film or a fluorescent
screen.
UT - Ultrasonic Testing
Ultrasonic testing uses high frequency sound energy to conduct
examinations and make measurements. Ultrasonic inspection can be used for
flaw detection/evaluation, dimensional measurements, material
characterization, and more.
Eddy Current Testing
Eddy-current testing uses electromagnetic induction to detect flaws
in conductive materials. There are several limitations, among them: only

conductive materials can be tested, the surface of the material must be
accessible, the finish of the material may cause bad readings, the depth of
penetration into the material is limited by the materials' conductivity, and
flaws that lie parallel to the probe may be undetectable.
In a standard eddy current testing a circular coil carrying current is placed in
proximity to the test specimen (which must be electrically conductive).The
alternating current in the coil generates changing magnetic field which
interacts with test specimen and generates eddy current. Variations in the
phase and magnitude of these eddy currents can be monitored using a second
'receiver' coil, or by measuring changes to the current flowing in the primary
'excitation' coil. Variations in the electrical conductivity or magnetic
permeability of the test object, or the presence of any flaws, will cause a
change in eddy current and a corresponding change in the phase and
amplitude of the measured current. This is the basis of standard (flat coil)
eddy current inspection, the most widely used eddy current technique.
Hardness tests:
Vickers hardness
A diamond indenter, in the form of a right
pyramid with a square base and an angle of
136 degrees between opposite faces is used
to put an indent on the sample by subjecting
it to a load of 1 to 100 kgf. The full load is
normally applied for 10 to 15 seconds. Then
the diagonals of the indentation left in the
surface of the sample after removal of the
load are measured using a microscope and
their average calculated.

F= Load in kgf
d = Arithmetic mean of the two diagonals, d1 and d2 in mm
HV = Vickers hardness
The Vickers hardness is calculated by the following formula
HV= F/D2 × Vickers constant (1.854).
A more convenient way is to use conversion tables. The Vickers hardness is given
as 700 HV/20, which means a Vickers hardness of 700, was obtained using a 20
kgf force. The advantages of the Vickers hardness test are that extremely accurate
readings can be taken, and just one type of indenter is used for all types of metals
and surface treatments.
Micro Vickers hardness is sometimes used when hardness is to be measured on a
micro level such as hardness of various phases of a material. Load here varies from
10g to 1kg.
 Rockwell Hardness Test:
The test method is based on indenting the test material with a diamond cone or
hardened steel ball indenter. The indenter is
forced into the test material under a
preliminary minor load usually 10 kgf. As
minor load is applied, a device responsible
for keeping track of the movement of
indenter notes this penetration by minor
load and sets it to zero as reference line
(datum position). Then in addition to minor
load, major load is applied for a period of
time ‘dwell time’. After this time major
load is removed while minor load is still
maintained. The removal of the major load

allows a partial recovery, so reducing the depth of penetration. The permanent
increase in depth of penetration, resulting from the application and removal of the
additional major load is used to calculate the Rockwell hardness number.
Based upon the type of indenter steel ball/ diamond cone and the amount of major
load various Rockwell hardness scales are present. As the steel ball indenter comes
in different diameters, a number of Rockwell hardness scales are formed each used
for different types of materials.
Rockwell hardness scales
Scale Indenter
Minor Load
F0
kgf
Major Load
F1
kgf
Total Load
F
kgf
Value of
E
A Diamond cone 10 50 60 100
B 1/16" steel ball 10 90 100 130
C Diamond cone 10 140 150 100
D Diamond cone 10 90 100 100
E 1/8" steel ball 10 90 100 130
F 1/16" steel ball 10 50 60 130
G 1/16" steel ball 10 140 150 130
H 1/8" steel ball 10 50 60 130
K 1/8" steel ball 10 140 150 130
L 1/4" steel ball 10 50 60 130

M 1/4" steel ball 10 90 100 130
P 1/4" steel ball 10 140 150 130
R 1/2" steel ball 10 50 60 130
S 1/2" steel ball 10 90 100 130
V 1/2" steel ball 10 140 150 130
Application of Rockwell Hardness Scales
HRA . . . . Cemented carbides, thin steel and shallow case hardened steel
HRB . . . . Copper alloys, soft steels, aluminum alloys, malleable irons, etc.
HRC . . . . Steel, hard cast irons, case hardened steel and other materials harder
than 100 HRB
HRD . . . . Thin steel and medium case hardened steel and pearlitic malleable iron
HRE . . . . Cast iron, aluminum and magnesium alloys, bearing metals
HRF . . . . Annealed copper alloys, thin soft sheet metals
HRG . . . . Phosphor bronze, beryllium copper, malleable irons HRH . . . .
Aluminum, zinc, lead
Rockwell superficial hardness test methods works on the same aforementioned
principles however the total load applied is typically 15, 30 or 45 kgf.

Rockwell Superficial Hardness Scales
Scale Indenter Type
Minor Load
F0
kgf
Major Load
F1
kgf
Total Load
F
kgf
Value of
E
HR 15 N N Diamond cone 3 12 15 100
HR 15 T 1/16" steel ball 3 12 15 100
HR 30 T 1/16" steel ball 3 27 30 100
HR 45 T 1/16" steel ball 3 42 45 100
HR 15 W 1/8" steel ball 3 12 15 100
HR 30 W 1/8" steel ball 3 27 30 100
HR 45 W 1/8" steel ball 3 42 45 100
HR 15 X 1/4" steel ball 3 12 15 100
HR 30 X 1/4" steel ball 3 27 30 100
HR 45 X 1/4" steel ball 3 42 45 100
HR 15 Y 1/2" steel ball 3 12 15 100
HR 30 Y 1/2" steel ball 3 27 30 100

HR 45 Y 1/2" steel ball 3 42 45 100
 The Brinell hardness Test
The Brinell hardness test method consists of indenting the test material with a 10
mm diameter hardened steel or carbide ball subjected to a load of 3000 kg. For
softer materials the load can be reduced to 1500 kg or 500 kg. The full load is
normally applied for 10 to 15 seconds in the case of iron and steel and for at least
30 seconds in the case of other metals. The diameter of the indentation left in the
test material is measured with a microscope. The Brinell harness number is
calculated by dividing the load applied by the surface area of the indentation.
The diameter of the impression ‘d1’ is the average of two readings at right angles
and the use of a Brinell hardness number table can simplify the determination of
the Brinell hardness. A properly written Brinell hardness number reveals the test
conditions, and looks like this, "80 HB 10/3000/15" which means that a Brinell
Hardness of 80 was obtained using a 10mm diameter hardened steel with a 3000
kilogram load applied for a period of 15 seconds. On tests of extremely hard metals
a tungsten carbide ball is used in place of the steel ball. Brinell hardness test results
in the deepest and widest of indentations and the hardness is averaged over a wider
region of the specimen compared to other test methods which are more localized

hence, it will account for multiple grain structures and irregularities of the
specimen. Basically, Brinell gives macro-hardness of a material.
 Shore/Durometer hardness method
This is mostly used in the plastic and rubber industries. A test force is worked out
and is applied upon a spherical or a conical-shaped indenter. This force is applied
to the specimen for a predetermined period of time. The resulting indentation is
converted into a hardness value by means of a dial gauge. Test loads range from
822 gf (A scale) to 4550 gf (D scale). Non-standard “micro” scales are also
available. These micro scales allow testing on thin or very narrow specimens.
 The International Rubber Hardness Degrees (IRHD)
This method as the name implies is reserved for hardness testing of rubbers of
various sizes and shapes especially used on rubber rings. An initial test load is
applied onto the specimen and the position is noted as reference point or zero. This
is followed by the total test force which increases the indentation. The distance
between the two points is determined and the IRHD hardness value is calculated.
Preliminary test forces are 8.46 gf for micro scales and 295.7 gf for regular scales.
Total test forces are 15.7 gf for micro and 597 gf for regular scales.
 Portable Hardness Tester:
It gives value of hardness at any angle and in any value by the principle of bounce
back.

Lab 5
Optical Emission Spectroscopy
____________

Principle:
Optical emission spectrometry involves applying electrical energy in the form of
spark generated between an electrode and a metal sample, whereby the vaporized
atoms are brought to a high energy state within a so-called “discharge plasma”.
This gives us qualitative and quantitative composition of the material.
Specifications of apparatus:
Following describes the brief specifications of the apparatus:
 This particular machine is a 5 based system i.e. it can detect alloys with 5
base metals Iron based alloys, Copperbased alloys, Aluminum based alloys,
Nickel based alloys, and Zinc based alloys
 It has 41 channels to detect 37 different elements
 The time provided for the application of spark is different for different
metals. For iron based alloys it is 30 sec, for aluminum based alloys it is 25
sec and for zinc based alloys it is 20 sec. least count of this machine is 0.001.
 It is a destructive operation in a sense that there remains a spotof spark on
the sample. The excitation sourceis high voltage spark approximately 906
volts.
 Temperature of table must be 35 degrees Celsius
 Vacuum 40-50 mT must be created
 Gas pressure must be 9-10
 Temperature of the room must be below 30o

 Sample must have thickness of 2mm.
Analysis
 The Intensity of an emission line (colour) is proportional to
concentration – allows measurement of ‘how much’ of each element
is present.
 A number of standards are run first to set up a calibration curve,
these take into account any matrix matching difficulties (i.e. overlap of
elements in some materials).
 Once calibration is completed numerous samples can be analysed.
 The sample is simply clamped into place, ‘sparked’ and a spectrum
collected.
 The spectrometer collects the intensity of light at all wavelengths and
compares this to the values for the calibration standard. This gives an
accurate value of the elements present in the sample.
 Multiple sparks are collected until concordant results are obtained
within an acceptable standard deviation.
 Further samples of the same alloy type can then be analysed.
 Different alloys require re-calibration before analysis can occur.

Maintenance
The main thing in its maintenance is its time to time calibration. After a certain
period of time, test on the standard sample of known composition provided by
the manufacturer is performed and standard results are calibrated
ASTM standards:
ATM standard 346 is followed in this lab.

Lab 6
Bio materials
____________

Introduction:
This lab is named so because it was designed to make hydroxy appetite. Further in
this lab we have two more machines:
 C-S determinator
 Potentiostat
C-S determinator
This particular machine CS-200 gives value up to 3 decimal places. It is used to
find the accurate %age of carbon and sulphur in sample. The principle of machine
is combustion of carbon and sulphur. A precisely weighed sample is combusted in
a small crucible with oxygen and a small amount of tungsten trioxide. Carbon in
the sample is oxidized to carbon dioxide or carbon monoxide. The sulfur is
oxidized to sulfur dioxide. These combustion gases are carried by oxygen into an
infrared (IR) cell where sulfur is detected as sulfur dioxide. Following sulfur
analysis, all of the carbonis converted to carbondioxide. The sulfur is converted to
sulfur trioxide and removed by filtration. The carbon dioxide is then measured in a
separate IR cell.
Particulars
 The determination of carbon and sulfur is done by non-dispersive (fixed)
infrared energy at precise wavelengths as the gases pass through their
respective IR absorption cells. The changes in energy are then observed at
the detectors and the concentration is determined.
 The average analysis time is 60 to 120 seconds. Heating is done by
induction furnace.
 The combustion gasses (CO2, H2O, SO2) coming from the furnace pass
through a dust filter.
 Temperature of combustion tube is approximately 1400o
Nitrogen and
oxygen gases are used in this machine. Nitrogen is to move stage while
oxygen is for combustion. We have absorbers magnesium per chlorate for

carbondioxide and sodium hydroxide with silicon is used for absorption of
sulphur dioxide.
 As the process might be slow so to increase the speed of process we use
cadmium as catalyst.
 Also cellulose filter is used for the purification of air. Maximum weight of
sample can be 1gm.
 For analysis of ferrous and non-ferrous sample there is difference of
accelerator. As ferrous have high melting point we cannot burn it at this
temperature in lab so we add accelerator to lower its melting point.
Accelerator in this case is a mixture of tin and tungsten. While non-ferrous
have very low melting point to avoid there melting or any such problem we
have to increase their melting point. We add iron chips to increase the
melting point.
How heating is Accomplished
Induction heating is done in these furnaces. In these furnaces heating of electrically
conducting object is done by electromagnetic induction, where eddy currents are
generated within the metal and resistance leads to Joule heating of the metal. An
induction heater consists of an electromagnet, through which a high-
frequency alternating current (AC) is passed.
H=I2
RT
Where ‘I’ is current, R is resistance and T is time.
How do Carbon effect Steel
Carbon is generally considered to be the most important alloying element in steel
and can be present up to 2% (although most welded steels have less than 0.5%).
Increased amounts of carbon increase hardness and tensile strength, as well as
response to heat treatment (harden ability). Increased amounts of carbon will
reduce weld ability.
How do Sulphur effect Steel
Sulphur is usually an undesirable impurity in steel rather than an alloying element.
In amounts exceeding 0.05% it tends to cause brittleness and reduce weld ability.

Alloying additions of sulfur in amounts from 0.10% to 0.30% will tend to improve
the machinability of steel.
 Potentiostat:
Potentiostat is a polarization technique that allows for
the controlled polarization of metal surfaces in
electrolytes, in order to directly observe cathodic and
anodic behaviors. Corrosion reactions can be monitored
or driven at the surface of a desired metal sample. A
variety of characteristics related to the
metal/environment pairing can be determined through
this technique.
A Potentiostat is an electronic instrument that controls the voltage difference
between working and reference electrodes, both of which are contained in an
electrochemical cell. The Potentiostat implements this control by injecting current
into the cell through an auxiliary or counter electrode.
3 electrodes are involved in working of machine:
 Working electrode
 Standard electrode
 Reference electrode
The potentiostatic technique is used to directly observe anodic and cathodic
behaviors of a metal surface in electrolytes. Polarization experiments are
performed with a computer controlled Potentiostat. A constant or a varying DC
potential (potentiostatic or potential dynamic, respectively), or a constant DC
current (galvanostatic) is applied to the metal of interest while it is immersed in the
electrolyte.

Lab 7
Jewelry & Hall marking
____________

Introduction:
This lab was related with the work of purity of the jewelry or precious metal like
gold and there stamping at state of the art level. We also study to calculate the
density of the unknown object.
Apparatus:
The brief explanation of the apparatus used is given below:
 X-ray fluorescence:
It is the emission of characteristic "secondary" (or fluorescent) X-rays from a
material that has been excited by bombarding with high-energy X-rays or
gamma rays. The phenomenon is widely used for elemental analysis and
chemical analysis, particularly in the investigation of metals, glass, ceramics
and building materials, and for research in geochemistry, forensic science and
archaeology.
Underlying physics:
When materials are exposed to short-wavelength X-rays or to gamma rays,
ionization of their component atoms may take place. Ionization consists of the
ejection of one or more electrons from the atom, and may occur if the atom is
exposed to radiation with energy greater than its ionization potential. X-rays
and gamma rays can be energetic enough to expel tightly held electrons from
the inner orbitals of the atom. The removal of an electron in this way makes the
electronic structure of the atom unstable, and electrons in higher orbitals "fall"
into the lower orbital to fill the hole left behind. In falling, energy is released in
the form of a photon, the energy of which is equal to the energy difference of
the two orbitals involved. Thus, the material emits radiation, which has energy
characteristic of the atoms present. The term fluorescence is applied to
phenomena in which the absorption of radiation of a specific energy results in
the re- emission of radiation of a different energy (generally lower).

Characteristic radiation:
Each element has electronic orbitals of characteristic energy. Following
removal of an inner electron by an energetic photon provided by a primary
radiation source, an electron from an outer shell drops into its place. There are a
limited number of ways in which this can happen, as shown in Figure 1. The
main transitions are given names: an L→K transition is traditionally called Kα,
an M→K transition is called Kβ, and an M→L transition is called Lα, and so
on. Each of these transitions yields a fluorescent photon with a characteristic
energy equal to the difference in energy of the initial and final orbital. The
wavelength of this fluorescent radiation can be calculated from Planck's Law:
The fluorescent radiation can be analyzed either by sorting the energies of the
photons (energy-dispersive analysis) or by separating the wavelengths of the
radiation (wavelength-dispersive analysis). Once sorted, the intensity of each
characteristic radiation is directly related to the amount of each element in the
material. This is the basis of a powerful technique in analytical chemistry.
Figure 2 shows the typical form of the sharp fluorescent spectral lines obtained
in the wavelength-dispersive method (see Moseley's law).
Primary radiation:
In order to excite the atoms, a source of radiation is required, with sufficient
energy to expel tightly held inner electrons. Conventional X-ray generators are
most commonly used, because their output can readily be "tuned" for the
application, and because higher power can be deployed relative to other
techniques. However, gamma ray sources can be used without the need for an
elaborate power supply, allowing an easier use in small portable instruments.
When the energy source is a synchrotron or the X- rays are focused by an optic
like a polycapillary, the X-ray beam can be very small and very intense. As a
result, atomic information on the sub-micrometer scale can be obtained. X-ray
generators in the range 20–60 kV are used, which allow excitation of a broad
range of atoms. The continuous spectrum consists of "bremsstrahlung"
radiation: radiation produced when high-energy electrons passing through the
tube are progressively decelerated by the material of the tube anode (the
"target"). Dispersion: In energy dispersive analysis, the fluorescent X-rays
emitted by the material sample are directed into a solid-state detector which
produces a "continuous" distribution of pulses, the voltages of which are

proportional to the incoming photon energies. This signal is processed by a
multichannel analyzer (MCA) which produces an accumulating digital
spectrum that can be processed to obtain analytical data. In wavelength
dispersive analysis, the fluorescent X-rays emitted by the material sample are
directed into a diffraction grating monochromatic. The diffraction grating used
is usually a single crystal. By varying the angle of incidence and take-off on the
crystal, a single X-ray wavelength can be selected. The wavelength obtained is
given by the Bragg Equation: where d is the spacing of atomic layers parallel to
the crystal surface.
Detection:
In energy dispersive analysis, dispersion and detection are a single operation, as
already mentioned above. Proportional counters or various types of solid-state
detectors (PIN diode, Si (Li), Ge (Li), Silicon Drift DetectorSDD) are used.
They all share the same detection principle: An incoming X-ray photon ionizes
a large number of detector atoms with the amount of charge produced being
proportional to the energy of the incoming photon. The charge is then collected
and the process repeats itself for the next photon. Detector speed is obviously
critical; as all charge carriers measured have to come from the same photon to
measure the photon energy correctly (peak length discrimination is used to
eliminate events that seem to have been produced by two X-ray photons
arriving almost simultaneously). The spectrum is then built up by dividing the
energy spectrum into discrete bins and counting the number of pulses registered
within each energy bin. EDXRF detector types vary in resolution, speed and the
means of cooling (a low number of free charge carriers is critical in the solid
state detectors): proportional counters with resolutions of several hundred eV
cover the low end of the performance spectrum, followed by PIN diode
detectors, while the Si (Li), Ge (Li) and Silicon Drift Detectors (SDD) occupy
the high end of the performance scale. In wavelength dispersive analysis, the
single-wavelength radiation produced by the monochromator is passed into a
photomultiplier, a detector similar to a Geiger counter, which counts individual
photons as they pass through. The counter is a chamber containing a gas that is
ionized by X-ray photons. A central electrode is charged at (typically) +1700 V
with respect to the conducting chamber walls, and each photon triggers a pulse-
like cascade of current across this field. The signal is amplified and transformed

into an accumulating digital count. These counts are then processed to obtain
analytical data.
X-ray intensity:
The fluorescence process is inefficient, and the secondary radiation is much
weaker than the primary beam. Furthermore, the secondary radiation from
lighter elements is of relatively low energy (long wavelength) and has low
penetrating power, and is severely attenuated if the beam passes through air for
any distance. Because of this, for high- performance analysis, the path from
tube to sample to detector is maintained under vacuum (around 10 Pa residual
pressures). This means in practice that most of the working parts of the
instrument have to be located in a large vacuum chamber. For less demanding
applications, or when the sample is damaged by a vacuum (e.g. a volatile
sample), a helium-swept X-ray chamber can be substituted, with some loss of
low-Z (Z = atomic number) intensities.
Chemical analysis
The use of a primary X-ray beam to excite fluorescent radiation from the
sample was first proposed by Glockerand Schreiber in 1928. [1] Today, the
method is used as a non- destructive analytical technique, and as a process
control tool in many extractive and processing industries. In principle, the
lightest element that can be analyzed is beryllium (Z = 4), but due to
instrumental limitations and low X-ray yields for the light elements, it is often
difficult to quantify elements lighter than sodium (Z = 11), unless background
corrections and very comprehensive inter-element corrections are made.
 Densitometer
Introduction:
The properties of materials are directly related with their microstructure and
hence density. For highly technical applications such as telecommunication
devices, densities above 95% of the relevant theoretical densities are required.
To measure density of solid and liquid samples, MRL is equipped with
Electronic Densitometer MD-300S which provides a highly accurate calculation

of specific gravity of almost any object of any shape. The density of rubber,
plastic, metals, glass, ceramic, food samples, wood and pharmaceuticals can be
measured with this instrument. The density resolution of the installed machine
is 0.001g/cmÂ³ and specific gravity less than one can be measured. The
machine is able to compensate water temperature and specific gravity of
solution on front switches, specific gravity is automatically calculated.
Working Principle
Commonly two methods are used for the determination of density of materials.
One is the direct measurement method. This method involves measurement of
the mass (in grams) of the body by weighing it and its volume (in centimeter
cube) by measuring its length (l), width (w) and height (h); as V= l x w x h.
Dividing the mass by volume gives the density in g/cm3.
The second and more reliable method is based on Archimedes' Principle which
states that an object immersed in a fluid is buoyed up by a force equal to the
weight of the displaced fluid. It is known that 1 ml of water has a mass almost
exactly equal to 1g. If an object is immersed in water, the difference between
the two masses (in grams) will equal (almost exactly) the volume (in ml) of the
object weighed. Knowing the mass and the volume of the object allows us to
calculate its density.
Densitometer

 Hall marking:
Hall marking is the process of marking precious metals about their purity
usually. This process was named after its history of marking of gold in
Europe in a big hall thus named after it. The apparatus used was laser
engraving machine.
Apparatus requirement:
Safety glasses must be worn. This apparatus uses 4 level lasers for
engraving. Usually used for stamping. It is better than manual engraving as
it has controlled material loss and symmetrical writings.
Purity units of gold:
In Asia Carrot is used as an impurity unit which is marked out of 24, while
in Europe finesse is used marked out of 1000. Copper metal is added as an
impurity to give strength to gold.
ASTM standards:
ATM standard 346 is followed in this lab.

Lab 8
Physical Vapor Deposition
____________

Introduction:
Physical vapor deposition (PVD) describes a variety of
vacuum deposition methods used to deposit thin films by the condensation of a
vaporized form of the desired film material onto various work piece surfaces (e.g.,
onto semi conductor wafers).
Sputtering:
Sputtering is the thin film deposition manufacturing process at the core of today’s
semiconductors, disk drives, CDs, and optical devices industries. On an atomic
level, sputtering is the process whereby atoms are ejected from a target or source
material that is to be deposited on a substrate - such as a silicon wafer, solar panel
or optical device - as a result of the bombardment of the target by high energy
particles.
The sputtering process begins when a substrate to be coated is placed in a vacuum
chamber containing an inert gas - usually Argon - and a negative charge is applied
to a target source material that will be deposited onto the substrate causing the
plasma to glow.
Free electrons flow from the negatively charged target source material in the
plasma environment, colliding with the outer electronic shell of the Argon gas
atoms driving these electrons off due to their like charge. The inert gas atoms
become positively charged ions attracted to the negatively charged target material
at a very high velocity that “Sputters off” atomic size particles from the target
source material due to the momentum of the collisions. These particles cross the
vacuum chamber and are deposited as a thin film of material on the surface of the
substrate to be coated.
Sputtering only takes place when the kinetic energy of the bombarding particles is
extremely high, much higher than normal thermal energies in the “Fourth state of
nature” plasma environment. This can allow a much more pure and precise thin
film deposition on the atomic level than can be achieved by melting a source
material with conventional thermal energies.

The number of atoms ejected or “Sputtered off” from the target or source material
is called the sputter yield. The sputter yield varies and can be controlled by the
energy and incident of angle of the bombarding ions, the relative masses of the
ions and target atoms, and the surface binding energy of the target atoms. Several
different methods of sputtering are widely used, including ion beam and ion-
assisted sputtering, reactive sputtering in an Oxygen gas environment, gas flow and
magnetron sputtering.
This technique is used in PCD coating process.
Advantages:
 PVD coatings are sometimes harder and more corrosion resistant than
coatings applied by the electroplating process
 Most coatings have high temperature and good impact strength, excellent
abrasion resistance.
 They are so durable that protective topcoats are almost never necessary.
 Ability to utilize virtually any type of inorganic and some organic coating
materials on an equally diverse group of substrates and surfaces using a wide
variety of finishes.
 More environmentally friendly than traditional coating processes such as
electroplating and painting.
 Low coating thickness (0.5-7 micron)
 Chemical resistivity
 Uniformity by rotation.
 Increase in hardness
 Self lubricated
 Electroplating defects are overcome by CVD- chemical vapor deposition

Applications:
As mentioned previously, PVD coatings are generally used to improve hardness,
wear resistance and oxidation resistance. Thus, such coatings use in a wide range
of applications such as:
 Aerospace
 Automotives
 Surgical/Medical
 Dies and moulds for all manner of material processing
 Cutting tools
 Firearms
 Optics
 Thin films (window tint, food packaging, etc.)
 Metals (Aluminum, Copper, Bronze, etc)
Apparatus Requirement:
Following requirements are fulfilled during experimentation:
 Vacuumed up to 10^-6 milli torr
 Etching for rough surfaces
 Biasing
 Gas center (inert argon)
Coating types:
There are three types of coating in PVD:
 Composite: nitrites of aluminum, zirconium, tin

 Nano composite: done at micro level with titanium nitride & silica nitride
 DLC-Diamond Like Coatings: chromium Aluminium nitride + silica Nitride
gives hardness
Coating thickness:
Coating thickness is given by:
𝑎2
− 𝑏2
4 × 𝐷 × 1000
𝑚𝑖𝑐𝑟𝑜𝑛𝑠
Where; a=outer circle diameter obtained by indent
b=inner circle diameter
D=diameter of ball used for indenting/ scratching
-PVD Apparatus overview

Lab 9
Scanning Electron Microscope
____________

Introduction:
A scanning electron microscope (SEM) is a type of electron microscope that
produces images of a sample by scanning it with a focused beam of electrons.
Principle:
Accelerated electrons in an SEM carry significant amounts of kinetic energy, and
this energy is dissipated as a variety of signals produced by electron-sample
interactions when the incident electrons are decelerated in the solid sample. These
signals include secondary electrons (that produce SEM images), backscattered
electrons (BSE), diffracted backscattered electrons (EBSD that are used to
determine crystal structures and orientations of minerals), photons (characteristic
X-rays that are used for elemental analysis and continuum X-rays), visible light
and heat. Secondary electrons and backscattered electrons are commonly used for
imaging samples: secondary electrons are most valuable for showing morphology
and topography on samples and backscattered electrons are most valuable for
illustrating contrasts in composition in multiphase samples (i.e. for rapid phase
discrimination). . Thus, characteristic X-rays are produced for each element in a
mineral that is "excited" by the electron beam. SEM analysis is considered to be
"non-destructive"; that is, x-rays generated by electron interactions do not lead to
volume loss of the sample, so it is possible to analyze the same materials
repeatedly.
Specifications:
Essential components of all SEMs include the following:
 Electron Source("Gun")
 Electron Lenses
 Sample Stage
 Detectors for all signals of interest
 Display / Data output devices

 Infrastructure Requirements:
o Power Supply
o Vacuum System
o Cooling system
o Vibration-free floor
o Roomfree of ambient magnetic and electric fields

Advantages:
Following are the advantages of the SEM:
 It can give us magnification up to 300000 times
 It can resolve the phases within the alloys
 It uses electron gun thus is very efficient

References:
Following references were used during report:
 cs-instruments.com
 http://www.microscopemaster.com/scanning-electron-microscope.html
 http://www.semteclaboratories.com/
 www.semicore.com
 en.wikipedia.org
Acknowledgements:
All the instructors help us a lot in learning to operate various apparatus. We had a
wonderful experience working with such a competitive staff.

internship report PCSIR

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