Mechanical and TribologicalBehaviour of Nano Fly Ash

Reinforced Hybrid Composites

Dr.S.K.Acharya,ProfessorRaghavendra Gujjala,PhD ScholarMechanical Engg DepartmentNIT Rourkela-769008

CONTENTS Introduction

Bio Fiber Composite

Background/Origin of the work

Nano Fly Ash

Experimental Aspects

Results And Discussion

Conclusions

What are composite materials ??

Metals & Alloys

Ceramics & GlassesPolymers

Carbon fibre reinforced plasticGlass fibre reinforced plastic

Metal matrix composites

Steel-Cordtyres Composites

Introduction Composite material is a multiphase material formed from a combination

of two or more materials that differ in composition or form, which arebonded together, but retaining their identities and properties. The outcomeof this composition is that the newly formed material has superiorproperties over the individual components.

Composite material consists of two or more different materials, combiningtogether through a interface, to form a new material. This new material canoffer better properties which can not be offered by either of the constituentmaterials separately.

Composites are comprised of two or more separate material, that whencombined lead to improved properties over the individual components.

Introduction Contd.. Composites have higher strength than conventional

materials due to aligned fibers carrying the load.

Composites are lighter than traditional materials. Theycan be designed to minimum weight without sacrificingstrength.

Why a Composite?

It reduces the weight of the components by 30% in comparisonto conventional material such as metal, plastic or ceramic.

The stiffness or strength needs to be doubled.

The number of sub-components has to be reduced.

The cost may be reduced.

The fatigue life or operating temperature should be increased.

A component with a zero coefficient of thermal expansion maybe obtained.

Natural Fibers

Bottlenecks

Advantages of Natural fiber Reinforcement

1. Environmental reasons:Renewable resource of raw materialThermally recyclable, biodegradable,Low energy consumption

2. Excellent specific strength & high modulus

3. Health & safety: less abrasive,safe manufacturing processes

4. Lower cost & reduced density of products

1. Variability2. Hydro-philicity (moisture)3. Weak interface

Why Bio-Fiber Composites ?

Flax Hemp Sisal CoirKenaf

Natural Fibers

CONSTITUENTS OF BIO- FIBRE COMPOSITE

+ =Fiber Resin Composite Material

NATURAL FIBERS

Jute Banana

Bamboo Sugarcane

They are - low-cost

- low density fibers - high specific strength and modulus

- low priced- recyclable

- biodegradable - nonabrasive

- easily available

and above all areECO-FRIENDLY

11

Natural Fibers: Applications

Advantage of Natural Fiber over man made fiber

Natural fiber composites are likely to be environmentally superior to glass fiber composites, in most cases for the following reasons:

1. Natural fiber production has lower environmentally impacts compared toglass fiber production.

2. Natural fiber composites have higher fiber content for equivalentperformance, reducing more polluting base polymer content

3. The light weight natural fiber composites improve fuel efficiency andreduce emission in the use phase of the component, especially in autoapplications.

4. Moreover, natural fibers are non-uniform with irregular cross sectionswhich make their structures quite unique and much different with man-made fibers such as glass fibers, carbon fibers etc.

Background/Origin of the work

Polymer composites filled with fibers and/or solid lubricants have beenwidely accepted as tribo-materials and used on the components supposed torun without any external lubricants. The former mainly improves themechanical strength and wear resistance of polymers, while the latterimproves friction characteristics and contributes to the control of wear.Tribological properties of polymer composites can also be greatly enhancedwith the addition of nano particles, such as nano-Al2O3/polyimide, nano-ZnO/polytetrafluoroethylene(PTFE) , and nano-TiO2/epoxy . One of thedistinct advantages of nano composites over micro composites lies in thatthe performance improvement is often achieved at relatively lowconcentration of the nano fillers, which is beneficial to the mechanicalproperties, processability, and esthetic appearance of the end products.

The term filler is very broad and encompasses a very widerange of materials which plays an important role for theimprovement in performance of polymers and their composites.Filler materials are used to reduce the material cost, to improve themechanical properties to some extent and in some cases to improveprocessability. Besides, it also increases properties like abrasionresistance, hardness and reduces shrinkages. Therefore a judiciousselection of matrix and the reinforcing phase can lead to acomposite with combination of strength and modulus comparableor even better than conventional metallic materials. The physicaland mechanical properties can further be modified by addition of asolid filler phase to the matrix body during the compositepreparation.

Jute, the so-called golden fiber from eastern India andBangladesh is one of the most common agro-fibers havinghigh tensile modulus and low elongation at break. If the lowdensity of this fiber is taken in to consideration, then itsspecific stiffness and strength are comparable to therespective quantities of glass fibers. The fiber has a highaspect ratio, high strength to weight ratio, is low in energyconversion, and has good insulation properties. The jute fibercomposites can be very cost-effective material especially forbuilding & construction industry, packing, automobile &railway coach interiors and storage devices.

The main chemical constituents of Jute are cellulose-61-71%hemicellulose-13-20% lignin-12-13%

Lignin - acts as a binder for the cellulose

fibers- behaves as an energy storage

system

Cellulose - high tensile strength of compositematerials.

Objective of the work

1.To explore the possibility of making compositeswith Nano Fly Ash as reinforcement in polymerbase.

2.Solid Particle Erosion wear behaviour of thecomposite.

3. Some Value added novel applications of Jute basedcomposites are also suggested. This would certainlyin a long way will improve the uses of Fly Ash inhigh priority areas, and would also ensureinternational market for cheaper substitution.

Introduction to Nanocomposites• Particulate composites:

– Matrix– Particulate Phase

• Reinforcing particles have at least one dimension (i.e. length, width, or thickness) on the nanometer scale

Why small?

Surface area:125 x (1 x 1 x 6) = 750 = 5 x 1505 x 5 x 6 = 150

In proceeding from a µm to nm scale the specific surface area increases by 3 orders of magnitude

EXPERIMENTAL ASPECTS

Jute fiber. E-Glass fiber. Flyash Epoxy resin: LY-556 and Hardener HY-951

Materials Required

E-Glass

ADVANTAGES High strength Low cost High chemical resistance Good insulating properties

DRAW BACKSLow elastic modulus.Poor adhesion to polymer.Low fatigue strength

EPOXYEpoxy resin (Araldite LY 556) having properties :-

• Excellent Mechanical Properties

• Good Fatigue Resistance

• Low Shrinkage

• Negligible shrinkage.

HardenerIn the present work Hardener (araldite) HY 951 is used. This has

viscosity of 10-20 poise at 25 °c. the hardener is taken 10 % ofvolume of polymer .

Fly ash Fly ash, also known as flue-ash, is one of the

residues generated in combustion, and comprisesthe fine particles that rise with the flue gases.Ash which does not rise is termed bottom ash. Inan industrial context, fly ash usually refers to ashproduced during combustion of coal.

SiO2 Al2O3 Fe2O3 TiO2 CaO MgO Na2O K2O Loss on ignition

48.32 31.2 8.23 2.56 1 2.1 1.2 1.35 3.5

Chemical composition of fly ash

Manufacturing technique used

Ingredients used for composite Preparation: -

Fiber:- Woven Jute Mats and glass fiber (layered stacking sequence)

Filler :- Fly Ash

Polymer:- Araldite LY 556 (CIBA GEIGY Ltd.)

Hardener :- HY951

Mould used for casting:-Per- pex sheet mould of dimension

150x60x6mm is usedMethod: -

Hand lay-up technique.Sl.no Symbol Stacking sequence1 L1 GGGG

2 L2 JJJJ

3 L3 JGGJ

4 L4 GJJG

5 L5 JGJG

J-Jute ply, G-Glass ply.

Name Fly ash Filler content

GGGG 0g 0g

JJJJ 0g 0g

JGGJ 2g 4g

GJJG 2g 4g

JGJG 2g 4g

composites samples

Details of erosion test rig. (1) Sand hopper. (2) Conveyor belt system for sand flow. (3) Pressure transducer. (4) Particle-air mixing chamber. (5) Nozzle. (6) X–

Y and θ axes assembly. (7) Sample holder

ASTM G 76Erosion test rig

Erosion Test:-

Test parameters

Erodent: - Silica sand

Erodent size (µm):- 200 ± 50

Impingement angle (α0):- 30, 45, 60, 90

Impact velocity (m/s):- 70

Erodent feed rate (g/min):- 4

Test temperature: - RT

Nozzle to sample distance (mm):- 10

Nozzle diameter 3

RESULTS AND DISCUSSIONS

SEM micrographs of fresh fly ash SEM micrographs of fly ash after ball milling for 15 hours

XRD patterns of fly ash before ball mill

XRD patterns of fly ash after ball mill ball-milled for 15 h,

38.23

184.82

72.18

100.23

123.23

165.89182.23

194.3

87.1

105.2

135.6133.05

152.23

180.3

0

50

100

150

200

250

Flex

ural

Str

engt

h M

pa

composite Samples

Flexural results of the composites

18.22

116.22

51.9459.23

68.2378.34

89.5696.28

73.46

85.2393.78

86.57

96.28

115.35

0

20

40

60

80

100

120

140Te

nsile

Str

engt

h M

pa

composite Samples

Tensile results of the composites

51.9456.23

62.35 62.168.23

0

10

20

30

40

50

60

70

80

JJJJ JJJJ 6g FA JJJJ 12g FA JJJJ 2g N FA JJJJ 4g N FA

Ten

sile

Str

engt

h M

pa

Composite Sample

72.1882

90100.23

123.23

0

20

40

60

80

100

120

140

JJJJ JJJJ 6g FA JJJJ 12g FA JJJJ 2g N FA JJJJ 4g N FA

Flex

ural

Str

engt

h M

pa

Composite Sample

0

1

2

3

4

5

6

7

0 10 20 30 40 50 60 70 80 90 100

Ero

sion

wea

r g/

g

Impingement angles

GGGG JJJJ

JJJJ+2g FA JJJJ+4g FA

Erosion Wear Of Composites

The hybrid composite shows enhanced properties due to theaddition of Nano fillers in comparison to micro fillers.

The Erosion behavior of jute changes from semi brittle to brittledue to addition of Nano fly ash.

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