Epoxy Composites Application 6p2l6x

MECHANICAL PROPERTIES & DRY SLIDDING WEAR BEHAVIOUR OF

GRAPHITE FILLER REINFORCED EPOXY COMPOSITES

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3. OBJECTIVES OF THE WORK: 

Conducting literature survey



Fabrication & processing of epoxy resin composites



Conducting density test and hardness test on the specimens



Studies on Dry sliding wear behaviour of the composite specimens using pin-on-disc machine.



Worn surface analysis using SEM



Analysis of the experimental results 2

1. INTRODUCTION TO COMPOSITES 

Composites: - Mixture or combination of diff. materials - Mainly made of matrix and reinforcement



Types of composites with respect to matrix - Polymer Matrix Composites [PMCs] - Metal Matrix Composites [MMCs] - Ceramic Matrix Composites [CMCs]

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POLYMER MATRIX COMPOSITES 

Most widely used , also known as FRPs



Mainly of two kinds: thermosets and thermoplastics



Polymers are ideal material as they are light weight



Abrasion and chemical resistant



Can be processed easily and posses desirable mechanical properties



Uses polymer base resin as matrix and fibers such as glass, carbon as reinforcement 4

Thermosets Epoxy

Phenolic polyamide resins

polyester

Thermoset materials 5

EPOXY: 

Low

molecular

weight

pre-polymers

or

higher

molecular weight polymer 

Easy to process



Contains at-least two epoxide group



Rarely exists as pure substances



High hot and wet strength properties



Good mechanical properties



Used in aerospace and defense applications 6

GRAPHITE 

Soft allotrope of carbon – Solid lubricant



The crystal lattice of graphite consists of hexagonal rings



Each carbon atom is covalently bonded to three other atoms in the plate



Bonded to each other by weak Van der Waals forces



Low shear strength and high compression strength



Graphite forms a lubrication film strongly adhered to the substrate surface 7

2.

LITERATURE SURVEY



B Suresha [1], made investigations on the dry sliding wear & two-body abrasive wear behavior of graphite filled carbon fabric reinforced epoxy composites. Excellent wear characteristics were obtained with carbonepoxy containing graphite as filler especially with carbon-epoxy containing 10 wt% graphite as filler.



K. M. Subbaya [2], made investigations on the Three-Body Abrasive Wear Behavior of Graphite Filled Carbon-Epoxy Composites Using Grey-Based Taguchi Approach. The results show that the addition of graphite particles into Carbon-Epoxy composite increased the wear resistance considerably.



B Suresha [3], made investigations on influence of graphite filler on two-body abrasive wear behavior of carbon fabric reinforced epoxy composites. Graphite filler in carbon-epoxy reduced the specific wear rate. Further, the wear volume loss drops significantly with increase in graphite content. 8



Subita Bhagat [4], made study on effect of graphite filler on Mechanical behavior of Epoxy composite which is prepared by compression molding machine. The obtained material has increased tensile strength property, break decreases slowly as filler concentration increases due stiffness increases with filler content, flexural strength increases of graphite content.



B.Suresha [5], here glass epoxy composite is used instead of epoxy. In his studies he had made three composite, they are glass epoxy with graphite, glass epoxy with silicon carbide(SiC), only just glass epoxy. Results shows graphite contribute in reducing friction and exhibited better wear resistant properties.



B.Suresha [6], made study on Mechanical and Tribological Properties of Glass–Epoxy composites with and without Graphite particulate filler. While testing for mechanical properties it was found that increase in tensile strength , tensile modulus but decrease in percentage elongation with increase in graphite filler. 9



M. Sudheer [7], done research to investigate the influence of graphite fillers on the dry sliding wear and abrasive wear behavior of carbon fabric reinforced epoxy composites. Wear behavior of 10 wt% graphite filled carbon epoxy composites are better compared to unfilled and lower graphite filled carbon fiber reinforced epoxy composites.



K. Kumaresan [8], made research on carbon fabric reinforced epoxy composites with and without silicon carbide filler for the dry sliding wear test conditions which include different applied load sliding velocity. Results showed that the surface hardness value of the SiC filled C-E composite is slightly higher than the unfilled composite.



Xiubing Li [9], made research on wear test of epoxy composites specimens paired with A36 steel specimen under air lubricated condition were carried out on a ring block wear tester typed M200. Results showed that as graphite content increasing, the wear volume decreases sharply first, then slightly goes up when graphite content is 30% volume. 10

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H. Ranganna [10], made study on the development and mechanical behavior of graphite/ granite filled epoxy hybrid composites. It was also found that the tensile strength were slightly higher for the composites having graphite as material. The impact fracture surfaces were later scanned using scanning electron microscopy.

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FABRICATION PROCESSES FOR COMPOSITES 

Open mould process -Hand lay up process -Spray lay up process -Vacuum bag moulding -Filament winding process



Closed moulding process -Pultrusion process -Compression moulding -Resin transfer moulding -Injection moulding 12

SPIT DIE COMPRESSION MOULDING

• Weight amount of polymer and is placed in lower half mould • The upper half of is moves downwards, pressing on polymer charge and forcing it to fill the mould cavity .

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MATERILAS FOR SPECIMEN FABRICATION  Epoxy

resin (LY556+HY951) as host matrix materials

 Graphite

filler (less than 100 micron meter) as reinforcement material



Hardener used for LY556 epoxy resin is Aradur HY951

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Details of samples prepared Sample

Wt. % of Matrix

Filler

C1

Epoxy

-------

------

C2

Epoxy

Graphite

10

C3

Epoxy

Graphite

20

C4

Epoxy

Graphite

30

C5

Epoxy

Graphite

40

Code

Filler

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Standards used in specimen testing ASTM Standards

ASTM D785

Properties to be tested

Hardness (Rockwell M Scale) (specimen size 10x10x3mm)

Dry sliding wear ASTM G99-05

(specimen size 10x10x3mm) 16

TESTING DETAILS Density test  Rockwell hardness test  Dry sliding wear behaviour on Pin-on-disc machine  Worn surface analogy using SEM 

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PIN-ON-DISC MACHINE 

It is a quick and easy method of kinetic friction and sliding wear measurement

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RESULTS AND DISCUSSION Effect of graphite filler content on density of composites Sample

Density (g/cc)

C0

1.15

C10

1.302

C20

1.374

C30

1.401

C40

1.434

Density (g/cc)

Density (g/cc)

1.5 1.4 1.3 1.2 1.1 C0

C 10

C 20 % of Filler Content

C 30

C 40

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Effect of graphite content on the hardness of neat epoxy Sample

Hardness (Rockwell M scale)

C0

52

C 10

53

C 20

55

C 30

56

C 40

64

Rockwell Hardness (M scale) 65

RHN

60

55

50

45 C0

C 10

C 20

Sample

C 30

C 40

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(a) speed 3m/s

0.45 0.4

COF

0.35

10N

0.3

20N

0.25 0.2

C0

C 10

C 20 C 30 % of Filler Content

C 40

Coefficient of friction as a function of filler content for 3m/sec 21

Coefficient of friction of different samples for speed 3m/s and 5m/s Sample

C0

C 10

C 20

C 30

C 40

Load (N)

Coefficient of friction 3 m/s

5 m/s

10

0.443

0.356

20

0.314

0.345

10

0.375

0.288

20

0.283

0.281

10

0.313

0.261

20

0.271

0.256

10

0.256

0.241

20

0.225

0.229

10

0.234

0.225

20

0.228

0.215

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Coefficient of friction as a function of filler content for 3m/sec (a) speed 3m/s

0.45

0.4

COF

0.35 10N 0.3

20N2

0.25

0.2 C0

C 10

C 20 % of Filler Content

C 30

C 40

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Coefficient of friction as a function of filler content for 5m/sec (b) speed 5m/s

0.45 0.4

COF

0.35

0.3

10N 20N

0.25 0.2 0.15 C0

C 10

C 20

C 30

C 40

% of Filler Content 24

Specific wear rate of different samples for different speeds samples for speed 3m/s and 5m/s Sample

C0

C 10

C 20

C 30

Load (N)

Specific wear rate, Ks×10-6 (mm3/Nm)

3m/s

5m/s

10

36.23

30.42

20

24.63

14.53

10

5.12

7.29

20

3.64

3.84

10

4.86

7.13

20

2.86

3.64

10

4.75

6.98

20

2.37

2.37 25

C 40

10

4.64

5.12

20

2.32

2.32

Specific wear rate as a function of filler content for 3m/s (a) speed 3m/s

SPECIFIC WEAR RATE, Ks×10-6 (mm3/Nm)

40 35 30

25 20

10N

15

20N

10 5 0 C1

C2 C3 C4 COMPOSITE SAMPLES

C5 26

Specific wear rate as a function of filler content for 5m/s

SPECIFIC WEAR RATE, Ks×10-6 (mm3/Nm)

(b) speed 5m/s

35 30 25 20 10N

15

20N 10 5 0 C1

C2

C3

C4

C5

COMPOSITE SAMPLES

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SEM images of worn surface of different percentage of graphite filled epoxy sample under 20N and at speed 5m/s C0

C10

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SEM images of worn surface of different percentage of graphite filled epoxy sample under 20N and at speed 5m/s C20

C30

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SEM images of worn surface of different percentage of graphite filled epoxy sample under 20N and at speed 5m/s

C40

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CONCLUSION Graphite can improve density, hardness and dry sliding wear properties of neat epoxy. Increase in the graphite content increases the hardness of polymer composites.

Increase in the graphite content increases the wear resistance of the polymer composites. Performance of graphite filled epoxy composites is found better than unfilled epoxy composites. 31

SCOPE FOR FUTURE WORK •The studies can be made by varying the filler material size (other than 100µm) with the base matrix. •Effect of graphite filler on a different matrix (other than epoxy) can be studied. •FEM analysis can be carried out in order to study the mechanical properties of composite specimens.

•A study on other forms of wear can be carried out in order to study the tribological behaviour of specimens. •The studies can be made for higher load (more than 20N) and higher speed (above 5m/sec). 32

REFERENCES 1.

B Suresha, Siddaramaiah, Kishore, S. Seetharamu, P. Sampath Kumaran, “Investigations on the influence of graphite filler on dry sliding wear and abrasive wear behaviour of carbon fabric reinforced epoxy composites” Wear, September 2009; Vol. 267(910), pp. 1405-1414.

2.

K. M. Subbaya, N. Rajendra, Y. S. Varadarajan, B. Suresha, “Multiple Response Optimization of Three-Body Abrasive Wear Behaviour of Graphite Filled Carbon-Epoxy Composites Using Grey-Based Taguchi Approach” Journal of Minerals and Materials Characterization and Engineering, 2012, pp. 876-884.

3.

B. Suresha, B.N. Ramesh, K.M. Subbaya, B.N. Ravi Kumar, G. Chandramohan “Influence of graphite filler on two-body abrasive wear behaviour of carbon fabric reinforced epoxy composites”, Materials and Design, April 2010; Vol. 31(4): pp. 1833-2000.

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4)

Subita Bhagat, Pardeep Kumar Verma , “Effect of Graphite Filler on Mechanical Behaviour of Epoxy Composites”, International Journal of Emerging Technology and Advanced Engineering, Volume 3, Issue 2, February 2013, ISSN 22502459.

5)

B.Suresha, G.Chandramohan, J.N Prakash, V. Balusamya and K.sankaranarayasamy, “The Role of Fillers on Friction and Slide Wear Characteristics in Glass-Epoxy Composite Systems”, Journal of Minerals and Materials Characterization and Engineering, Nov 2006, Vol. 5(1), pp. 87-101.

6)

B.Suresha, G. Chandramohan, N. M. Renukappa, Siddaramaiah, “Mechanical and Tribological Properties of Glass–Epoxy Composites with and Without Graphite Particulate Filler”, Journal of Applied Polymer Science, Volume 103 (4), February 2007, pp. 2472-2480.

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7.

M. Sudheer, K. Hemanth, K. Raju, Thirumaleshwara Bhat, “Enhanced Mechanical and Wear Performance of Epoxy/glass Composites with PTW/Graphite Hybrid Fillers”, 3rd International Conference on Materials Processing and Characterization, pp. 975 – 987, 2014.

8.

K. Kumaresan, G. Chandramohan, M. Senthilkumar, B. Suresha, S. Indran, “Dry Sliding Wear Behaviour of Carbon Fabric-Reinforced Epoxy Composite with and without Silicon Carbide”, Composite Interfaces, 18 (2011), pp. 509–526.

9.

Xiubing Li, Yimin Gao, Jiandong Xing, Yu Wang, Liang Fang, “Wear reduction mechanism of graphite and MoS2 in epoxy composites”, School of Material Science and Engineering, Xian Jiaotong University, Xian 710049, PR China, 2004, pp. 279–283. 35

10. H. Ranganna, M. Ashok Kumar, A. Ramesh, N. Madhuva Reddy, N. karthikeyan, V. Nikil Murthy, S. Raja Kumar, S. Mahboob Basha, E.V. Subba Reddy, “ Development and behaviour of mechanical properties of graphite/granite filled epoxy hybrid composites”, International journal of fibre and textile research, ISSN 2277-7156, 2013, pp. 57-59.

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