Selva Project

7/29/2019 Selva Project

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SYNTHESIS AND CHARACTERIZATION OF NEW

ALUMINIUM ALLOY WITH MWCNT COATED

WITH NI-P ELECTROLEES COATING

A PROJECT REPORT

Submitted by

T.SAKTHIVEL (84509144037)

R.SATHISH (84509144039)

S.SELVAKUMAR (84509144040)

U.MUJEPER RAHMAN (84509144505)

In partial fulfillment for the award of the degree

of

BACHELOR OF ENGINEERING

IN

MECHANICAL ENGINEERING

IMAYAM COLLEGE OF ENGINEERING KANNANUR-621206

ANNA UNIVERSITY: CHENNAI 600025

MAY 2013


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BONAFIDE CERTIFICATE

Certified that this project report SYNTHESIS AND CHARACTERISATION

OF NEW ALUMINIUM ALLOY WITH MWCNT COATED WITH Ni-P is

the bonafide work of S.SELVAKUMAR who carried out the project work

under my supervision.

SIGNATURE SIGNATURE

Mr.C.Francis vimalraj. M.Tech., Mr.A.Thiagarajan. M.Tech.,

HEAD OF THE DEPARTMENT GUIDED BY

Mechanical department Mechanical department

Imayam College of engineering Imayam College of engineering

Kannanur-621206 Kannanur-621206

Submitted for Anna University viva-voce examination held on ___________

INTERNAL EXAMINER EXTERNAL EXAMINER


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ACKNOWLEDGEMENT

We express our sincere gratitude to Dr.R.Nallusamy. Ph.D., Principal of

Imayam College of Engineering, Kannanur, Thuraiyur. who gave us the

opportunity to frame the project to the fullest satisfaction.

We are extremely grateful to Mr.C.Francis vimalraj. M.Tech,Head of the

Department of Mechanical Engineering who have been instrumental in guiding

us, with their valuable suggestions.

We express our hearty thanks to our supervisor Mr.A.Thiagarajan.

M.Tech, Department of Mechanical Engineering for his valuable guidance and

encouragement for the successful completion of this project.

We would like to express our deep sense of thanks to the entire faculty of

Mechanical Engineering Department and to all our friends.

We express our soulful thanks to our dear parents who have been the major

contributor of inspiration and encouragement to us throughout our project.

We thank God Almighty for his blessings without which we would have not

initiated the project.


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ABSTRACT

Nanotechnology draws its attention in the current world scenario. Physical

and chemical properties of materials are tends to changes at nano scale. Among

various forms of nano materials, carbon nanotube earns a rightful place in the field

of nanotechnology. Carbon nanotubes are posses excellent electrical properties due

to its high aspect ratio i.e., length to diameter, typically 103 to 104. Current work

deals with the synthesis and characterization of aluminium alloy. Reinforced with

carbon nanotubes are used for the work.

Aluminium has been widely in aerospace and terrestrial system, more and

more attention has been paid for expanding the market of its alloy in automotive

industries and decrease of energy consumption of vehicles. In this proposed project

work, it is planned to prepare al-al2 o3 alloys using multi wall carbon nano tube.

After preparation of alloy the material will be tested to evaluate the mechanical

properties. Nanotubes are dispersed in aluminium alloy, thus prepared are tested to

increase the mechanical properties and then characterized using XRD and SEM.


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TABLE OF CONTENTS

CHAPTER NO. TITLE PAGE NO.

ABSTRACT i

LIST OF TABLE v

LIST OF FIGURE iv

1 INTRODUCTION

1.1 Aluminium Alloys 1

1.2 Advantages 3

1.3 Applications 3

2 LITERATURE REVIEW

2.1 Aluminium Alloy 5

2.2 Carbon nanotubes 6

3 POWDER METALLURGY

3.1 Powder metallurgy 13

3.2 Advantages 13

3.3 Procedures 14

3.3.1 Blending 14

3.3.2 Compaction 15

3.3.3 Sintering 17


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4 EXPERIMENTAL PROCEDURE

4.1 Compaction Process 19

4.2 Sintering 24

4.3 Ni-P Coating 25

4.3.1 Electroless nickel coating 26

4.3.2 Electroless Ni-P coating 28

4.4 Experimental Setup 31

4.4.1 Electroless Plating Bath 31

5 CHRACTERIZATION

5.1 Hardness Test 37

5.1.1 Rockwell Hardness Test 38

5.1.2 Vicker Hardness Test

5.2 Wear 44

5.3 Compressive Strength

5.4 Scanning Electron Microscope


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LIST OF FIGURES

S.No. FIGURES PAGE NO.

1 Carbon nanotube structure and helicity 8

2 Schematic diagram of arc-discharge method 9

3 Powder metallurgy process 16

4 Sintering furnace 17

5 Die 20

6 Weighing machine 21

7 Mixing of powder 22

8 Compression 23

9 Muffle furnace 24

10 Scanning electron microscope 33

11 Internal structure of SEM 35

12 Rockwell hardness 39


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LIST OF TABLE

S.NO DESCRIPTION PAGE NO.

1 Composition Of Samples 21

2 Rockwell hardness test 41

3 Compressive strength 42

4 composition of chemicals 30


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INTRODUCTION

1.1 ALUMINIUM ALLOY

From Wikipedia, the free encyclopedia

Cast aluminium alloy rear wheel of Bootie Folding Bicycle

We see Aluminium used around us everywhere. From aluminium windows

oraluminium doors you find in your house, to aluminium foil your mom packs

your sandwiches in, and the decorative aluminium adorning your (thats right)

aluminium windows; aluminium is widely used in a majority of situations around

the house. What you probably didnt know that aluminium is an ideal choice in

several key industries.

In fact, aluminium is the third most common element in the Earth's crust,

making it the most abundantly available metal on Earth. Being extremely

lightweight, aluminium can be used to make lightweight, yet very durable alloys.

Apart from that, aluminium is a non-magnetic material, making it ideal in some

industrial uses. It also conducts both heat and electricity nearly as good as copper

does.
http://www.tradekey.com/ks-aluminumhttp://www.tradekey.com/ks-aluminum-windowhttp://www.tradekey.com/ks-aluminum-doorhttp://www.tradekey.com/ks-aluminum-foilhttp://www.tradekey.com/ks-aluminum-windowhttp://www.tradekey.com/ks-aluminumhttp://www.tradekey.com/ks-aluminumhttp://www.tradekey.com/ks-aluminumhttp://www.tradekey.com/ks-aluminumhttp://en.wikipedia.org/wiki/File:Bootie_bicycle_3_bootiebike.JPGhttp://en.wikipedia.org/wiki/File:Bootie_bicycle_3_bootiebike.JPGhttp://www.tradekey.com/ks-aluminum-windowhttp://www.tradekey.com/ks-aluminum-doorhttp://www.tradekey.com/ks-aluminum-foilhttp://www.tradekey.com/ks-aluminum-windowhttp://www.tradekey.com/ks-aluminumhttp://www.tradekey.com/ks-aluminumhttp://www.tradekey.com/ks-aluminumhttp://www.tradekey.com/ks-aluminumhttp://www.tradekey.com/ks-aluminum


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Aluminiumalloys are alloys in which aluminium (Al) is the predominant

metal. The typical alloying elements

are copper, magnesium, manganese, silicon and zinc. There are two principal

classifications, namely casting alloys and wrought alloys, both of which are further

subdivided into the categories heat - treatable and non-heat-treatable. About 85% of

aluminium is used for wrought products, for example rolled plate, foils

and extrusions. Cast aluminium alloys yield cost-effective products due to the low

melting point, although they generally have lowertensile strengths than wrought

alloys. The most important cast aluminium alloy system is Al-Si, where the high

levels of silicon (4.0% to 13%) contribute to give good casting characteristics.

Aluminium alloys are widely used in engineering structures and components where

light weight or corrosion resistance is required.[1]

Alloys composed mostly of aluminium have been very important

in aerospace manufacturing since the introduction of metal skinned aircraft.

Aluminium-magnesium alloys are both lighter than other aluminium alloys and

much less flammable than alloys that contain a very high percentage of

magnesium.[2]

Aluminium alloy surfaces will keep their apparent shine in a dry

environment due to the formation of a clear, protective layer of aluminium oxide.

In a wet environment, galvanic corrosion can occur when an aluminium alloy is

placed in electrical contact with other metals with more negative corrosion

potentials than aluminium.

Aluminium alloy compositions are registered with The Aluminium

Association. Many organizations publish more specific standards for the

manufacture of aluminium alloy, including the Society of Automotive

Engineers standards organization, specifically its aerospace standards subgroups.
http://en.wikipedia.org/wiki/Alloyshttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Copperhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Manganesehttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Zinchttp://en.wikipedia.org/wiki/Castinghttp://en.wikipedia.org/wiki/Heat_treatmenthttp://en.wikipedia.org/wiki/Extrudinghttp://en.wikipedia.org/wiki/Tensile_strengthhttp://en.wikipedia.org/wiki/Aluminium_alloy#cite_note-ReferenceA-1http://en.wikipedia.org/wiki/Aerospace_manufacturinghttp://en.wikipedia.org/wiki/Aluminium_alloy#cite_note-2http://en.wikipedia.org/wiki/Aluminium_oxidehttp://en.wikipedia.org/wiki/Galvanic_corrosionhttp://en.wikipedia.org/wiki/The_Aluminum_Associationhttp://en.wikipedia.org/wiki/The_Aluminum_Associationhttp://en.wikipedia.org/wiki/Society_of_Automotive_Engineershttp://en.wikipedia.org/wiki/Society_of_Automotive_Engineershttp://en.wikipedia.org/wiki/Alloyshttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Copperhttp://en.wikipedia.org/wiki/Magnesiumhttp://en.wikipedia.org/wiki/Manganesehttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Zinchttp://en.wikipedia.org/wiki/Castinghttp://en.wikipedia.org/wiki/Heat_treatmenthttp://en.wikipedia.org/wiki/Extrudinghttp://en.wikipedia.org/wiki/Tensile_strengthhttp://en.wikipedia.org/wiki/Aluminium_alloy#cite_note-ReferenceA-1http://en.wikipedia.org/wiki/Aerospace_manufacturinghttp://en.wikipedia.org/wiki/Aluminium_alloy#cite_note-2http://en.wikipedia.org/wiki/Aluminium_oxidehttp://en.wikipedia.org/wiki/Galvanic_corrosionhttp://en.wikipedia.org/wiki/The_Aluminum_Associationhttp://en.wikipedia.org/wiki/The_Aluminum_Associationhttp://en.wikipedia.org/wiki/Society_of_Automotive_Engineershttp://en.wikipedia.org/wiki/Society_of_Automotive_Engineers


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1.2 ADVANTAGES

Low cost

High strength

Light weight

Corrosion resistance

Good electrical conductivity

Ductility

Durability

Thermal conductivity

1.3 APPLICATIONS

Automobile

Aerospace

Electricity

Home appliances

Constructions

Marine


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1.4 PROPERTIES OF ALUMINIUM

Density - 2.7 g/cm

Melting point - 660 C

Yield strength 7 to 11 Mpa

Youngs modulus 70 Gpa

Poisson ratio 0.35

Non-magnetic material


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LITERATURE SURVEY

2.1 ALUMINIUM ALLOY

Effect of composition on friction coefficient of Cu-aluminum composites,

Jaroslav Kovacik, Stefan Emmer, Jozef Bielek, ubomir

In this paper reveals that that with increasing concentration of aluminium

with Cu, the coefficient of friction and wear rate decreased. However, in the case

of low voltage and high current density, it is required to employ materials with a

very high specific electrical conductivity, good thermal conductivity and low

friction coefficient. Such conditions are fulfilled only by Cu-Aluminium composite

materials

Microstructure of Cu&Al2o3 surface composite on a copper substrate,

Wenming Songa, b, Gui-rong Yang a, b,, Jin-jun Luc,

In this paper reveals that the microstructure and hardness of the surface

infiltrated composite (Cu/ Al2o3) layers produced on copper substrates. High

electrical and heat conductive copper is widely used in optics, electrical contact

and heat conducting materials. Their low strength and poor wear resistance are

required to improve with the developing industry.

Interfacial design of Cu-based composites prepared by powder metallurgy

for heat sink applications Th. Schubert ,, B. Trindade , T. Weigarber , B.

Kieback

The use of SiC or diamonds particles as reinforcements in copper based

composites is considered very attractive to meet the increasing demands for high

performance heat sink materials and packages.


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Wear and mechanical properties of sintered coppertin composites

containi graphite or molybdenum disulfide Hirotaka Kato a,, Masahiro Takamaa,

Yoshiro Iwai b, Kazuo Washida c, Yoshinori Sasaki c

The lubricant graphite and MoS2 powders were coated with Cu to reinforce

their bonding to the Cu particles in the composites during sintering. The friction

and wear properties of the materials were improved

Wear resistance of WC particle reinforced copper matrix composites, P.K.

Deshpande, R.Y. Lin

Tungsten, being a refractory metal, provides some degree of wear and arcing

resistance when used with copper as an electrical contact material. Its wear

resistance is better than that of wear-resisting tool steels. Tungsten carbide

undergoes no phase changes during heating and cooling and retains its stability

indefinitely.

Study of wear mechanisms in copper-based Sic (20% by volume)

reinforced composite, Dhokey a,, R.K. Paretkar b

Copper-based composites appear to be a promising material for engineering

applications due to their excellent thermo physical properties coupled with better

high temperature mechanical properties as compared to pure copper.

2.2 CARBON NANOTUBE

Structure plays major role in determining its properties. The material under

consideration, carbon nanotube is nothing but a rolled sheet of graphite. Graphite

consists of layer of carbon atoms, within the layers the atoms are arranged at the

corners of hexagon which fill the carbon plane. The carbon atoms are strongly

(covalent) bonded to each other and carbon-carbon distance ~0.34mm.


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Carbon nanotubes are considered to be a rolled single sheet of grapheme [1].

Grapheme sheets are seamless cylinder derived from honeycomb lattice,

representing a single atomic layer of crystalline graphite. Single walled carbon

nanotubes are considered as a cylinder with only one graphene sheet. SWNT are

completely described by a single vector C (chiral vector)

C=na1+na2

Where, n & m are integers, a1 & a2 are unit vectors. The direction of the nanotube

axis is perpendicular to this chiral vector.

Multi-walled carbon nanotubes are collection of concentric SENT. MWNT

may be formed from coaxial cylindrical curved, coaxial polygonized or small

graphite sheet [2]. The length of chiral vector C is the circumference of the

nanotube and is given by the relation

C=a (n2+nm+m2)

In the case of SWNT, three types of nanotubes exist. They are classified by

the pair of integers (n, m) which is related to chiral vector. (a) When n=m, the

nanotube is called arm chair type ( =0 ). (b) When m=0 then it is of zigzag

type ( =30 ) otherwise, (c) when n m, it is a chiral tubes and takes a value

between 0 to 30 . The value of (n, m) determines chiralitys of nanotubes and

affects the optical, mechanical and electronic properties.


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Carbon Nanotube Structure


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SYNTHESIS OF CARBON NANOTUBES

ARC-DISCHARGE METHOD

Carbon nanotubes were first reported by Sumio Lijima in the carbonaceous

deposits on the cathode obtained during the DC arc discharge process of a graphite

electrode in helium gas. The arc discharge method is still the only way to obtainhighly graphitized MWNTs without using metal catalyst.


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Inert gas such as helium or argon, other ambient gas discharge has been

extensively used to produce CNTs. Large quantities of CNTs has been produced by

the presence of metal catalyst such as Ni, Co, Fe, S,Y etc,. In this method, arcing is

carried out between a stationary anode and rotating cathode. Both the electrodes

are made of graphite, but the densification differs. The cathode is rotated to

maximize the yield of the CNT [3].


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Arc is struck using a DC supply providing 100-150 A/cm2 current densities

and 20-40 V. the power supply unit is an AC/DC inverter TIG power source.

Graphite with diameter 11mm (99.7% purity) is used as anode for arcing. Arcing is

carried out with a rotating graphite disc as counter electrode. A thick copper metal

plate holds the graphite cathode disc. The cathode disc is rotated and the speed is

maintained constant (5 rpm to 20 rpm) for each experiment.

A servo motor feed the anode towards the cathode in order to maintain the

electrode gap constant (1 mm). During arcing, soot is continuously deposited on

cathode, which is continuously scraped off using thin blade. In this process

chamber is operated in open air and without use of additional catalyst.

PURIFICATION

Carbon nanotubes produced by arc discharged method contains

carbonaceous impurities commonly increases with decreases in diameter.

Carbonaceous impurities include amorphous carbon, fullerenes. Fullerenes can be

easily removed owing to their solubility in certain organic solvents. Amorphous

carbon is also relatively easy to eliminate because of its high density of defects,

which allow it to be oxidized under gentle condition [4].

Purification methods of CNTs can be basically classified into three

categories namely chemical, physical and a combination of both. The chemical

method purifies CNTs based on the idea of selective oxidation where in

carbonaceous impurities are oxidized at faster rate than CNT and the dissolution of

metallic impurities by acids. The physical method separates CNTs from impurities

based on the differences in their physical size, aspect ratio, gravity and magneTIC

properties etc.


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The crude deposit scraped from the cathode is crushed using a pestle and

mortar to obtain fine powders. Then it is heated in open air in closed tubular

furnace. The samples are oxidized at 550 for 2 hours. Then the tubes are washed

in distilled water and Toluene so as to remove any water and organic soluble

impurities. Then the tubes are ultrasonicated in acetone so that they are

disagglomerated and subsequently dried in air [typically at 110 ] to drive away

the moisture.

PROPERTIES OF CNT

CNT processes many useful and unique properties such as

High electrical conductivity

Very high tensile strength

Very elastic 18% elongation to failure

Highly flexible can be bent considerably without damage

High thermal conductivity

Low thermal co-efficient of expansion

Highly absorbent

High aspect ratio (length=1000*diameter)

Light weight

The strength of sp2 C-C bonds gives amazing mechanicals properties for

nanotubes. The stiffness of materials measured terms of its Youngs modulus. The


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Youngs modulus of CNYs can be as high as 1Tpa, which is approximately five

times higher than steel. The Ultimate tensile strength of nanotubes can be up to 63

Gpa, around 50 times than steel.

Depending upon the structure, CNTs can be metallic or semi conducting.

Some metallic CNTs have conductivity 1000 times greater than that of copper.

Carbon nanotubes are very good thermal conductors along the tube axis. It will be

able to transmit up to 6000Watts per meter per Kelvin at room temperature (Cu-

385 Watts per meter per Kelvin). The temperature stability of CNT is estimated to

be up to 2800 in vacuum and about 750 in air.

POWDER METALLURGY

Powder is a forming and fabrication technique consisting of three major

stages. First the primary material is powdered, divided into many small individual

particles. Next the powder is injected into a mold or passed through a die to


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produce a weakly cohesive structure very near the dimensions of the object

ultimately to be manufactured.

Pressures of 10-50 tons per square inches are economically used. Also, to

attain the same compression ratio across more complex pieces, it is often necessary

to use lower punches as well as an upper punch. Finally the end part is formed by

applying pressure, high temperature, long setting times or any combination thereof.

Two main techniques used to form and consolidate the powder are sintering

and metal injection molding. Recent developments have made it possible to use

rabid manufacturing techniques which use the metal powder for products. Because

with this technique the powder is melted, and not sintered better mechanical

strength can be accomplished.

3.1 ADVANTAGES OF POWDER METALLURGY

1) No or only little amount of cutting and machining

2) High utilization rate of materials, over 95%;

3) Sizes of parts are consistent and stable;

4) Materials can be adjusted according to customers requirements;

5) Based on customers needs, surface parts are processed improving

strength and hardness

6) As for mass production, compared to machining, powder metallurgy high

efficiency, low cost.


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3.2 PROCEDURE TO BE CARRIED IN POWDER METALLURGY

The steps involved in making aluminium alloy by powder metallurgy

are

Blending

Compaction

Sintering

3.2.1 BLENDING

Powders are to be blended or mixed properly for obtaining the required

properties after sintering. In this process the powder and blender are mixed

together very finely. A lubricant is also employed some times to reduce the friction

and hence obtaining a finer mixing. The lubricant should be removed of the die

before submitting it for sintering as the process of lubricant may change the

properties of the object. Many types of blends are used for the manufacturing of

various parts by powder metallurgy technique.

The metal powder is mixed with lubricant and optional alloying elements to

form a homogeneous blend. 0.5-1.5% lubricant is normally added in the mix, and

metallic sterrate and waxes are commonly used lubricants. The main function of

lubricant is to reduce the friction between the powder mass and the surfaces of the

tool, die walls, core rods etc

This assists the achievement of uniform density from top to bottom of the

compact of equal importance is the fact that the reduction of friction also makes it

easier to eject the compact. As an alternative to pre alloyed powders, alloying


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elements can be added the mix powders. The most commonly used alloying

element is carbon, which is added as graphite powder.

3.2.2 COMPACTION

Compacting is done for shaping of the powder in to the required shape. In

this the mixed mixer is subjected to pressure and due to the application of pressure

the gap between the molecules gets reduced and the powder becomes compact and

gains sufficient strength to with stand ejection and handling.

Pressures applied on the powder should be strictly regulated as if low

pressures then the part generated will be very fragile in nature. If the pressure

applied is more then there may be a deformation of tool. In general a pressure of 1

to 150 nm2

Simply this method used to make a shaped specimen like a cake and it will

be easily brokened by hands when heating then the specimen will become stronger.

The following figure explains the working methodology of the compaction

process


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3.2.3 SINTERING

DEFINITION


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The thermal treatment of a powder is compact at a temperature below the

melting point of the main constituent, for the purpose of increasing its strength by

bonding together.

SINTERING ATMOSPHERES

The operation is almost invariably carried out under a protective atmosphere,

because of the large surface areas involved, and at temperatures between 60 and

90% of the melting-point of the particular metal or alloys.

SINTERING FURNACE

Control over heating rate, time, temperature and atmosphere is required for

reproducible results. The type of furnace most generally favored is an electrically

heated one through which the compacts are passed on a woven wire mesh belt. The

belt and the heating elements are of a modified 80/20 Nickel/chromium alloy and

give a useful life a temperature up to 1150 . For higher temperatures walking


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beam furnaces are preferred, and these are increasingly being used as the demand

for higher strength in sintered parts increases. Silicon carbide heating elements are

used can be operated up to 1350 . For a special purposes at still higher

temperature molybdenum heating elements can be used, but special problems are

involved, notably the readiness with which molybdenum forms a volatile oxide.

Molybdenum furnaces must operate in a pure hydrogen atmosphere. This process

is carried out for increasing the strength and also the hardness of the part. In this

part is subjected to heating without any pressure for certain period of time under

highly controlled conditions.

Sintering is concerned with

a. Diffusion

b. Densification

c. Recrystallization and grain growth

EXPERIMENTAL PROCEDURE


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EXPERIMENTAL PROCEDURE IN POWDER COMPACTION AND

SINTERING

4.1 COMPACTION PROCESS

AIM

To compact the powder in certain composition by using micro controlled

compression machine.

POWDER USED

1. ALUMINIUM METAL POWDER (PURE)

2. AL2O3

3. MWCNT

LUBRICANT

Zinc sterrate is used as the lubricant the percentage of zinc sterrate is 0.9-1%

as per Hoganas metallurgy manual. The mechanism employed is try lubrication

BINDERS

Ethanol is used as a binders or additives in order to dispersed CNT

uniformly with (AL+ AL2O3)

METAL PURCHASED


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The materials are purchased in material form for fabrication by powder metallurgy

process. Aluminium the base matrix material, titanium carbide and CNT is added

for enchasing strength. Zinc sterrate is added for lubrication and bonding between

the composites.

DIE

COMPOSITION OF POWDER

Raw materials used in the experiments are high purity aluminium (>99.9%), AL2O3

and CNT.

The additions of CNT are 0.25%, 0.5%, 0.75% and 1% (mass fraction). The

chemical compositions of the test composites are listed in table 1.

METAL COMPOSITION TABLE


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Composites no. AL2O3 % CNT % AL

1 5 0.25 Balance

2 5 0.5 Balance

3 5 075 Balance

4 5 1 Balance

5 5 1.25 Balance

WEIGHTING INDEX

Required amount of aluminium, AL2O3, MWCNT along with zinc sterrate is

weighed with digital weighing machine. The blend is prepared for different

compositions of each powder material are weighted individually for the required

composition using digital weighing scale.

MIXING (BLENDING) OF POWDERS


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The measured blend is taken in a glass beaker and stirred walk with the help

of a stirrer made by glass. The stirring has to be done properly to get the

homogeneous mixture.

FILLING THE DIE

The prepared blend is poured into the die and filled to the desired level.

Using filler the blend is filled thoroughly into the die for better compaction.

COMPACTION


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The die is placed safely into the MCTM machine. The load is then applied

gradually to the die for compaction.

EXTRUSION OF THE SPECIMEN

Extruded specimens (green sample)

The dimensions of the extruded specimens are measured using vernier

caliper.

Length of the specimen : 10 mm

Diameter of the specimen: 20 mm


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COATING

The extruded specimens are coated with aluminium to prevent the green

compact from oxidation. There after the specimen must be handled carefully

because it having the chance of getting brokened easily it likes a cake piece and

this should heated in the muffle furnace for getting the expected specimen what

really we want.

4.2 SINTERING

The bonding of adjacent surface of particles is in compact by heating.

Sintering strengthens a powder and mass and normally produces densification, and

in powdered metals, Recrystallization. The specimens are placed in a fine sand

bath and it uniformly distributes the heat to the specimen. The specimens are

submerged in the sand and the bath containing the specimens is placed inside


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muffle furnace for sintering process. The sintering temperature should be below

1the melting point of magnesium. Since chosen 500oC whereas the melting point

magnesium is 650oC. After reaching the desired temperature, furnace is kept for 3

hours.

The sand bath containing the specimens is withdrawn after 12 hours

SPECIMEN AFTER SINTERING

The specimens are checked for damage like cracks and deformation by

physical observation. No cracks are found. Thus required specimens are obtained.

The specimens are tested in order grasp the properties like the tribological and

mechanical.

4.3 ELECTROLESS COATING:

Electroless coating processes deposit metallic coating on a substrate without

the use of an external voltage or current. They are commonly referred to as

chemical metal deposition because the electrons required to bring about the

discharge of metal ions are produced by a chemical reaction in solution. Deposition

of metal is made from solution containing reducing agents .Such deposits from

only on certain catalytically active surfaces (autocatalytic deposition).The electrons

needed to reduce the metal ions are provided by the reducing agents R which

surrender n electrons, while getting oxidized to R(n+).The simplified from of the

reaction which describes the Electroless process is given as follows:


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It is properly named autocatalytic, because the oxidation of the reducing

agent can start or become self-sustained only at the deposition metal surface.

Plating can be done on non-catalytic base materials, after suitable activation of the

surface involved. Electroless deposits of nickel, copper, gold, silver, cobalt,

palladium etc. and of alloys involving one or more of these metals have been

produced in this process on various metallic and non-metallic substrates. In

contrast to electroplating, Electroless plating does not involve electric field

distribution. As a consequence uniformity of coating thickness could be achieved

even on intricate part geometries.

4.3.1 ELECTROLESS NICKEL COATING:

As already mentioned, a number of metals like nickel, copper, gold, cobalt,

palladium, silver etc. can be deposited by Electroless process. However, the bulk

of the deposits produced today are based on nickel. It has excellent mechanical and

electrochemical properties such as hardness, wear, abrasion and corrosion

resistance. Mainly due to this it has excellent commercial potential across a wide

Aerospace

machine

oil/chemical

miscl

printing

computer


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spectrum of industrial application in the field of electronics, computers, aircraft

parts, textile industry, automobiles, valves, dies etc.

ADVANTAGES:

Major advantages of Electroless coating over the electro deposition

process include:

Formation of a uniform deposit on irregular surfaces

Direct deposition on conductors and surface activated non-conductors

Formation of less porous deposits

Good wear resistance

Good corrosion resistance.

DISADVANTAGES:

The major drawback of EN coating is its high cost of production

due to various factors such as:

Cost of chemical used

Wastage in the form of nickel bearing sludge

Poor nickel recovery from the bath etc

Electroless nickel bath decomposition

Due to these reasons, the EN coating process efficiency is reported to

be poor order of only 50%

4.3.2 ELECTROLESS NICKLE PHOSPHOROUS:


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Electroless Nickel Phosphorous (EN) coatings have been used

either as protective or decorative coating in industries such as electronics,

computer, aerospace, printing, automotive, textile, plastics, optics, paper and food

(parker, 1972). Some of the outstanding characteristics of EN coatings are superior

corrosion and wear resistance, excellent uniformity, wide range of thickness, good

solder ability, improved mechanical and physical properties (Baudrand,1978).EN

deposition is carried out with:

A. Nickel chloride and/or nickel sulphate as the source of nickel

B. Sodium hypophosphite or sodium pyrophosphate as the reducing agent

C. A salt of an organic acid as a buffer

D. A mild complexing agent for nickel.

Deposits from these reducing agents contain a maximum of 14

wt., % phosphorus. Hydrazine hydrate is also used as a reducing agent for

production of high purity nickel deposits. For the controlled deposition of the

metal, numbers of parameters like temperature of deposition, pH of the bath,

concentration of the reducing agent etc., are to be monitored closely during

deposition. Improper control of one or more of these parameters might result in

deposits with widely fluctuating properties. For better stability and utility of the

plating bath, specific stabilizers and complexing agents are employed.

4.3.3 EXPERIMENTAL DETAILS:

PREPARATION OF SPECIMEN:

The substrate material used ALUMINIUM alloy with a size

25mm10mm. The chemical composition of the alloy is given below. The samples


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were abraded with emery sheet upto 2000SiC paper before the pretreatment

processes.

TABLE: chemical composition of the aluminium alloy

Al (wt., %) 9.1

Zn (wt., %) 0.64

Mn (ppm) 0.17

Fe (ppm) 0.01

Mg Balance

TABLE: CEN COATING BATH AND OPERATION

NiSO4.6H2O 5.2g/200ml


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NaH2PO2. H2O 6g/200ml

HF 2.4ml/200ml

CH3COONa.3 H2O 3.2g/200ml

NH32HF 1.6g/200ml

Thiourea (ppm) 0.4ml/200ml

PH 9-10, 7, 4-5

Temperature 87 2

Time 1hr

The bath of 200ml contains the above chemicals mixed. The

pH should not be more or less than 4-10.

4.4 EXPERIMENTAL SETUP:

4.4.1 MATERIALS PROCURED:


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4.4.2 ELECTROLESS PLATING BATH:

The electrolyte bath was heated indirectly through an electrically heated

water bath. The temperature of the water bath was controlled by an ON/OFFF

relay and Proportional Integral Derivative (PID) controller. Temperature of the


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electrolyte bath was monitored using a thermometer. The experimental setup is

show in the Fig. The pH of the electrolyte bath was maintained at 4-10 by adding

sodium hydroxide solution. The total volume of the plating bath was 200ml. The

coating duration is 1 hour after which the bath decomposes as shown.

IMPLEMENTATION OF EXPERIMENT

SCANNING ELECTRON MICROSCOPE

SCANNING ELECTRON MICROSCOPE

Materialselection

Procurement

Preparation of specimen and

pretreatment process

Ni-P coating on the substrate

SEM test and conclusions


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The Scanning electron microscope (SEM) is a type of electron microscopethat images the sample surface by scanning it with a high-energy beam of electrons

in a raster scan pattern. The electrons interact with the atoms that make up the

sample producing signals that contain information about the samples surface

topography, composition and other properties such as electrical conductivity.

The types of signals produced by an SEM include secondary electrons, back-

scattered electrons (BSE), characteristics X-rays, light (cathodoluminescence), andspecimen current and transmitted electrons. Secondary electrons detectors are

common in all SEMs, but it is rare that a single machine would have detectors for

all possible signals. The signals result from interactions of the electron beam with

atoms at or near the surface of the sample.

In the most common or standard detection mode, secondary electron

imaging or SEI, the SEM can produce very high-resolution images of a sample

surface, revealing details about less than 1 to 5 nm in size. Due to the very narrow

electron beam, SEM micrographs have a large depth of field yielding a

characteristic three-dimensional appearance useful for understanding the surface

structure of a sample.


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Because the intensity of the BSE signal is strongly related to the atomic

number (Z) of the specimen, BSE images can provide information about the

distribution of different elements in the sample. For the same reason, BSE imaging

can image colloidal gold immune-labels of 5 or 10 nm diameter which would

otherwise be difficult or impossible to detect in secondary electron images in

biological specimens.

Characteristics X-rays are emitted when the electron beam removes an inner

shell electron from the sample, causing a higher energy electron to fill the shell and

release energy. These characteristics X-rays are used to identify the composition

and measure the abundance of elements in the sample.

INTERNAL STRUCTURE OF SCANNING ELECTRON MICROSCOPE

A source (electron gun) of the electron beam which is accelerated down the

column.

A series of lenses (condenser and objective) which act to control the

diameter of the beam as well as to focus the beam of the specimen

A series of apertures (micron-scale holes in a metal film) which the beam

passes through and which affect properties of that beam.

Controls for specimen position (x,y,z height) and the orientation (tilt,

rotation)


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An area of beam/specimen interaction that generates several types of signals

that can be detected and processed to produce an image or spectra.

High magnification SEM images of some of the rod like structures showing

different CNT configurations


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MICROSTRUCTURE OF AL ALLOY WITH TIC

a) AL alloy + 0.25% CNT shows the uniform description throughout the

sample.

b) AL alloy +0.5% CNT spot out of CNT

c) AL composites +0.75% CNT crater formation in the sample

d) AL composites +1% CNT formation of agglomeration over the AL alloy.


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HARDNESS

The metals handbook defines hardness as resistance of metal to plastic

deformation, usually by indentation. However the term may also refer to stiffness

or temper or to resistance to scratching, abrasion, or cutting. It is the property of a

metal, which gives it the ability to resist being permanently, deformed (bent,

broken, or have its shape changed), when a load is applied. The greater hardness of

the metal, the greater resistance it has to deformation.

In mineralogy the property of matter commonly described as the resistance

of a substance to being scratched by another substance. In metallurgy hardness is

defined as the ability of a material into resist plastic deformation.

The dictionary of metallurgy defines the indention hardness as the resistance

of a material to indention. This is the usual type of hardness test

HARDNESS MEASUREMENT METHODS

There are three types of tests used with accuracy by the metals industry; they

are the Brinell hardness test the Rockwell hardness test and the wickers hardness

test. Since the definition of metallurgic ultimate strength and hardness are rather

similar, it can generally be assumed that the strong metal s also a hard metal. The

way the tree of these hardness tests measure a metals hardness is to determine

metals resistance to the penetration of a non-deformable ball or cone.

The tests determine the depth which such a ball or cone will sink into the

metal, under a given load, within a specific period of time.


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The following are the most common hardness test methods used in todays

technology;

1. Rockwell hardness test

2. Brinell

3. Vickers

4. Knoop

5. Shore

ROCKWELL HARDNESS TEST

The Rockwell scale is a hardness scale based on the indentation hardness of

a material. The Rockwell test determines the hardness by measuring the depth of

penetration of an indenter under a large load compared to the penetration made by

a preload. There are different scales, denoted by a single letter that use different

loads are indenters. The result is a dimensionless number noted as HRA, where A

is the scale letter. When testing metals, indentation hardness correlates linearly

with tensile strength. This important relation permits economically important non

destructive testing of bulk metal deliveries with light weight, even portable

equipment, such as hand-held Rockwell hardness testers.


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TESTING MACHINE

INTRODUCTION

The Rockwell scale is a hardness scale based on the indentation hardness of

a material. The Rockwell test determines the hardness by measuring the depth of

penetration of an indenter under a large load compared to the penetration made by

a preload. There are different scales, denoted by a single letter that use different

loads are indenters. The result is a dimensionless number noted as HRA, where A


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is the scale letter. When testing metals, indentation hardness correlates linearly

with tensile strength. This important relation permits economically important non

destructive testing of bulk metal deliveries with light weight, even portable

equipment, such as hand-held Rockwell hardness testers.

OPERATION

The determination of the Rockwell hardness material involves the

application of a minor load followed by a major load, and then noting the depth of

penetration, vis a vis, hardness value directly from a dial, in which a harder

material gives a higher number. The chief advantage of Rockwell hardness is its

ability to display hardness values directly, thus obviating tedious calculations

involved in other hardness measurement techniques. It is typically used in

engineering and metallurgy. Its commercial popularity arises from its speed,

reliability, robustness, resolution and small area of indentation.

In order to get a reliable reading the thickness of the test piece should be at

least 10 times the depth of indentation. Also, readings should be taken from am flat

perpendicular surface, because convex surfaces give loser readings. A correction

factor can be used if the hardness of a convex surface must be measured.


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TABLES

ROCKWELL HARDNESS TEST

Table 1:

CNT % TIC % AL HARDNESSVALUE

(HV)

0.25 5 Bal 80

0.5 5 Bal 85

0.75 5 Bal 91

1 5 Bal 82

1.25 5 Bal 84

COMPRESSIVE STRENGTH

DEFINITION

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 50Mpa,

whereas a material such as soft sandstone may have Compressive strength as low

as 5 or 10Mpa.

Compressive strength is often measured on a universal testing machine,

these ranges from very small table top systems to ones with over 53 MN capacities.

Measurements of Compressive strength are affected by the specific test method


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and conditions of measurement. Compressive strengths are usually reported in

relationship to a specific technical standard.

COMPRESSION

On an atomic level, the molecules or atoms are forced apart when in tension

where as in compression they are forced together. Since atoms in solids always try

to find an equilibrium position, and distance between other atoms, forces arise

throughout the entire material which appose both tension and compression.

The phenomena prevailing on an atomic level are therefore similar. On a

macroscopic scale, these aspects are also reflected in the fact that the properties of

most common materials in tension and compression are quite similar.

TABULATION

Sample Compressive strength (Mpa)

1 415

2 431

3 465

4 466

STRESS STRAIN DIAGRAM

By definition, the Compressive strength of a material is that value of

uniaxial Compressive stress reached when the material fails completely. The


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Compressive strength is usually obtained experimentally but means of a

Compressive test. The apparatus used for this experiment is the same as that used

in a tensile test however, rather than applying a uniaxial tensile load; a uniaxial

Compressive load is applied. As can be imagined, the specimen (usually

cylindrical) is shortened as well as spread laterally. A stress-strain curve is plotted

by the instrument and would look similar to the following;

The difference in values may therefore be summarized as follows;

1. On compression, a specimen wills shorten. The material will tend to spread

in the lateral direction and hence increase the cross sectional area.

2. In a compression test the specimen is clamped at the edges. For this reason,

a frictional force arises which will appose the lateral spread.

WEAR

INTRODUCTION


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In materials science, wear is erosion or sideways displacement of material

from its derivative and original position on a solid surface performed by the action

of another surface.

Wear is related to interactions between surfaces and more specifically the

removal and deformation of material on a surface as a result of mechanical action

of the opposite surface the need for relative motion between two surfaces and

initial mechanical contact between asperities is an important distinction between

mechanical wear compared to other process with similar outcomes.

The definition of wear may include loss of dimension from plastic

deformation if it is originated. However, plastic deformation such as yield stress is

excluded from the wear definition if it doesnt incorporates a relative sliding

motion and contact against another surface despite the possibility for material

removal, because it then lacks the relative sliding action of another surface. Impact

wear is in reality a short sliding motion where two solid bodies interact at an

exceptional short time interval. Previously due to the fast execution, the contact

found in impact wear was referred to as an impulse contact by the nomenclature.

Impulse can be described as a mathematical model of a synthesized average on the

energy transport between two travelling. Cavitations wear is a form of wear where

the erosive medium or counter-body is a fluid. Corrosion may be included in wear

phenomenon but the damage is amplified and performed by chemical reactions

rather than mechanical action.

MEASUREMENT

A standard result review for wear tests, defined by the ASTM international

and respective subcommittees such as committee G-2, should be expressed as loss


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of material during wear in terms of volume. The volume loss gives a truer picture

than weight loss, particularly when comparing the wear resistance properties of

materials with large differences in density. For example, a weight loss of 14 g in a

sample of tungsten carbide +cobalt (density=14000 kg/m3) and a weight loss of 2.7

g in a similar sample of aluminium alloy (density=2700 kg/m3) both result in the

same level of wear (1 cm3) when expressed as a volume loss. The inverse of

volume loss can be used as a comparable index of wear resistance. Standard wear

tests are only used for comparative material ranking as a specific test parameter as

stipulated in this method. For more realistic values of material deterioration in

industrial applications it is necessary to conduct wear testing under conditions

simulating the exact wear process.

The working life of an engineering component is expired when dimensional

losses exceed the specified tolerance limits. Wear, along with other aging

processes such as fatigue and creep in association with stress concentration factors

such as fracture toughness causes materials to progressively degrade, eventually

leading to material failure at an advanced age. Wear in industrial application is oneof a limited number fall factors in which on object losses its usefulness and

economic implication can be of enormous value to the industry.

TYPES

The study of process of wear is the part of the discipline tribology. The complex

nature of wear has delayed its investigations and resulted in isolated studies


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towards specific wear mechanism or process. Some commonly referred to wear

mechanisms include

1. Adhesive wear

2. Abrasive wear

3. Surface fatigue

4. Fretting wear

5. Erosive wear

A number of different wear phenomenonss are also commonly encountered and

presented in the literature. Impact cavitations, diffusive and corrosive wear are all

such examples. These wear mechanisms, however, do not necessarily act

independently and wear mechanisms are not mutually exclusive. Industrial wear

are commonly described as incidents of multiple wear mechanisms occurring in

unison. Another way to describe industrial wear is to define clear distinctions in

how different friction mechanisms operate, for example distinguish betweenmechanisms with high or low energy density. Wear mechanisms and / or sub-

mechanisms frequently overlap and occur in a synergistic manner, producing a

greater rate of wear than the sum of the individual wear mechanisms.

HARDNESS TESTING MACHINE (VICKERS HARDNESS TEST):


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Hardness test for evaluating the influence o different percentage of

surfactants SLS, C-TAB in hardness of the specimen coated.

The Vickers hardness test method consists of indenting the material with

a diamond indenter, in the form of a right pyramid with a square base and an angle

of 136 degrees between opposite faces subjected to a load of 1to 100 kgf. The full

load is normally applied for 10 to 15 seconds. The two diagonals of the indentation

left in the surface of the material after removal of the load are measured using a

microscope and their average calculated. The area of the sloping surface of the

indentation is calculated. The Vickers hardness is the quotient obtained by dividing

the kgf load by the square mm area of indentation.

HARDNESS TEST FOR FOLLOWING MODULES:


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SLS (sodium lauryl sulphate):

Fig: micro hardness Vs concentration of SLS

Increase in concentration of SLS increases the hardness.

SLS gives maximum hardness when added at 0.8 g/l

SURFACE ROUGHNESS TEST:

SURFACE ROUGHNESS TESTING MACHINE (PERTHOMETER):

A perthometer is a measuring instrument for the characterization of

the roughness of surfaces.

The perthometer functions similarly as a second record player. With a

palpation point one drives on the surface of a solid body along. The unevenness

are led from the probe into the equipment and converted there into electrical


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signals. These signals serve for the determination of different characterisTIC

values. Which characterize the surface roughness?

SLS (sodium lauryl sulphate):

INFERENCE:

Increase in concentration of SLS increases the surface roughness to a

certain point and then it decreases due to agglomeration of particles.

SLS gives maximum surface roughness when added at 0.6 g/l


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RESULT

Rockwell hardness test in table and fig: 14 shows the hardness value

increase gradually 26% from AL composites (AL+TIC) sample to 0.25% CNT,

from 0.25% CNT to 0.75% CNT is increasing after that the hardness value is 35%

decreasing from 0.75% CNT and above, because of as agglomeration reaction.

CNT particles interact with each other leading to cluttering of particles and

consequently settling down. Eventually the densities of CNT particles in the melt

start decreasing there by lowering the hardness value.

.

RESULT AND CONCLUSION

FROM MWNTS SUNTHESIS, THE FOLLOWING CONCLUSION

ARE DRAWN

The production MWNTs are made very simple and cost effective.

More yield was attained by the simplified arc discharge technique

Economic analysis of the synthesis of MWNTs shows the technique

used in the present research is very cheap with better yield than the

conventional technique.

The results prove that MWNTs are good in quality and easily mixes

with matrix powders with less agglomeration that lead to enhanced

properties.


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FROM MWNTS REINFORCED AL ALLOYS, THE FOLLOWING

CONCLUSIONS DRAWN:

The hardness are improved considerably with the addition of CNTs,

but the relatively less

When CNT concentration is beyond 1 wt%

The decrease in the properties is due to the agglomeration of CNTs

due the vander-waals force of attraction between each nanotubes

particles

The hardness indentation study reveals that hardness increased with

the addition of MWNTs it may be due to CNTs and grains refine

technique, which associated with the addition of CNTs

Compression strength of the material will increase with the addition

of CNT and corresponding the there will be decrease in the wear rate.

Concentration of MWNTs added to newly formulated alloys increase

the corrosion resistance increased due the passivatuion and galvanic

properties of CNTs.


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