Journal of Minerals & Materials Characterization & Engineering, Vol. 8, No.7, pp 513-530, 2009
jmmce.org Printed in the USA. All rights reserved
513
Influence of SiO2 Fillers on Sliding Wear Resistance and Mechanical
Properties of Compression Moulded Glass Epoxy Composites
B. Shivamurthya, Siddaramaiahb and M.S. Prabhuswamyc
a.Department of Mechanical Engineering , K.V.G. College of Engineering, Kurunjibag,
Sullia-574237, D.K. Karnataka, India.
bDepartment of Polymer Science and Technology, and
cDepartment of Mechanical Engineering,
Sri Jayachamarajendra College of Engineering, Mysore – 570 006, India
*Corresponding Author: [e-mail]
ABSTRACT
The E-glass woven fabric-epoxy (LY 556) (GE) composites have been fabricated with varying
amounts of silicon oxide (SiO2) particulate filler viz., 3, 6 and 9 wt % by compression molding
followed by hot curing. The fabricated composites were characterized by mechanical properties
such as tensile behaviour, flexural behaviour and interlaminar shear strength (ILSS). The effect
of silica content on the sliding wear properties such as wear loss, specific wear rate and
coefficient of friction of GE composites have been investigated at velocity of 5m/s and constant
abrading distance of 1200 m with different loads viz., 30N, 60N and 90N by using pin-on-disc
machine. Wear out surface of all the composites were studied using scanning electron
microscopy (SEM).
1. INTRODUCTION
Polymer based materials are finding increasing use in many applications owing to their strength,
lightness, ease of processing and availability of wider choice of systems [1]. One of the areas
where their use has been found to be particularly advantageous is the situation involving contact
wear. Due to the low coefficient of friction and also the ability to maintain loads, some specific
grades of polymer are used in place of the traditional metal based materials in recent times [2,3].
It is therefore, imperative to give greater thrust to the examination of this aspect through
increased research activities in the materials. One such possible method to widen the approach is
to adopt fillers/whiskers into the polymeric matrix systems. A second method would be to resort

514 B. Shivamurthy, Siddaramaiah and M.S. Prabhuswamy Vol.8, No.7
to the use of continuous fibrous/woven cloth/and high performance fiber cloths like carbon,
aramid and basalt in many forms as reinforcement and study its response to wear and friction. In
view of above two methods, many researchers have studied with various shapes, sizes, types and
compositions of fibers and fillers in many numbers of matrices [4–16]. However, the woven
fabric composites are getting acceptance in many engineering applications such as in circuit
board, marine, aerospace, transportation and other industries for several reasons. They are
commonly used in industry to manufacture composite components due to their ease of use,
improve structural performance and reduction in cost. They provide better resistance to impact
than unidirectional composites and display behavior that is closer to that of a fully isotropic
material [12-14]. Modification of woven fabric reinforced composites by incorporation of fillers
has been a popular research activity in the plastics industry since the properties of resultant
materials may be significantly changed by the introduction of fillers and fabrics [15].
Suresha et al [24] investigated the friction and wear behavior of glass-epoxy composite with and
without graphite. They fabricated neat glass-epoxy composite and graphite filled glass-epoxy
composite with three different percentages of filler. They concluded the graphite filled glass-
epoxy composite shows higher resistance to slide wear as compared to plain glass-epoxy
composites. Gewen et al [28] investigated the mechanical and tribological properties of phenolic
resin- based friction composite filled with several inorganic fillers. They observed the petroleum
coke increases the bending strength and hardness in phenolic resin based friction composites.
The talcum powder (TP) and hexagonal boron nitride were used as friction modifier, increases
the wear resistance of the phenolic resin based composites with in the volume fraction 5-10%
and 5-15% respectively. Further increase in volume fraction of friction modifier decreases the
bending strength and harmful to the wear resistance. Bulent et al [31] studied hybrid friction
materials made up of basalt fiber and ceramic fiber. They kept ceramic fiber content constant at
10% volume and varied basalt fiber from 0 to 40% and they observed the coefficient of friction
increased with increasing fiber content. The specific wear rate decreases with increase in total
fiber content up to 30% by volume, further increase in fiber volume increase the specific wear.
Increasing sliding speed and disc temperature resulted in increase in wear rate and size of the
wear debris at higher load. Zhang et al [36] investigated the mechanical properties and wear
properties of silicon carbide (SiC) and alumina (Al2O3) whisker- reinforced epoxy composites.
Silicon carbide and alumina whiskers can significantly improves the flexural modulus and wear
resistance of the epoxy composites. Various researchers [16-35] have reported that the wear
resistance of polymers is improved by the addition of fillers such as mica, talc, calcium
carbonate, kaolin, wallastonite, feldspar, graphite, MoS2, CuO, CuS, Al2O3 etc.
Though literature survey cited above reveals that, there is an ample scope to understand and
establish the wear mechanism of glass woven fabric reinforced particulate filler filled epoxy
composites. In this research article authors reported the sliding wear behavior of silicon dioxide
(SiO2) particulate filler loaded glass fabric-epoxy composites subjected to three different loads

Vol.8, No.7 Influence of SiO2 Fillers on Sliding Wear Resistance and Mechanical Properties 515
with constant velocity and abrading distance. The wear loss, specific wear rate and coefficient of
friction have been measured and compared with the unfilled glass- epoxy composite. Also, the
effects of SiO2 filler content on mechanical properties of the composites have been studied.
2. EXPERIMENTAL
2.1. Materials
In this investigation, composites were fabricated using bidirectional plain-woven E-glass fabrics
(density of 200 g/m2) as reinforcement. Epoxy resin LY556, hardener HT907 and accelerator
DY062 supplied by M/s. Huntsman Polymers, Germany used as matrix material. 30µ size silicon
oxide (SiO2) particles obtained by M/s. Jyothi chemicals, India, were used as filler.
The matrix was prepared by mixing epoxy resin, LY 556 and hardener HT 907 in the ratio
100:80 by volume at 600C. Silicon oxide fillers are dried in controlled temperature of 130 0C for
about 4 hrs before incorporation into epoxy. The calculated amount of SiO2 is incorporated to the
epoxy mixture with constant stirring followed by 2 % by weight of accelerator DY06.
The composite of 300 mm x 300 mm x 3mm were fabricated by compression moulding method.
The resin was coated on 16 layer of E-glass fabric using brush and roller and it was kept in
between the pressing plates of 350 mm x 350 mm size. A layer of polyester film was provided in
between the plate and composite surface for easy release and to obtain smooth and uniform
surface on the composites. Resin impregnated stock of 16 layers of fabrics was pressed in H-type
hydraulic press (capacity 40T) under pressure of 0.5 MPa and temperature 140oC for about 2 hr.
The composition of fabricated composites is given in Table 1.
Table 1. Formulation of fabricated SiO2 filled glass –epoxy composites.
Composite
Code
Content of SiO2
filler (Wt. %)
Resin content
(Wt. %)
Content of E-glass cloth
(Wt. %)
GE 0 50 50
3SGE 3 47 50
6SGE 6 44 50
9SGE 9 41 50
2.2. Techniques
The fabricated composites have been characterized by physico-mechanical and tribological
behaviours Density of composites was measured according to ASTM D 792 – 86 (displacement
method) using Mettler electronic balance with an accuracy of ± 0.0001g/cc. Surface hardness of

516 B. Shivamurthy, Siddaramaiah and M.S. Prabhuswamy Vol.8, No.7
composite was investigated as per ASTM D 785 on Rockwell hardness testing machine for 10kg
minor load and 140kg major load. Tensile behaviours as per ASTM- D 638 were investigated by
using Loyds LR 100K, Universal tensile testing machine. A three point bending technique was
adopted for flexural test as per ASTM-D790 standard for all composites. The impact strength
was determined using izod impact tester pendulum type (PSI make, India) as per ASTM-D256
specification. The interlaminar shear strength (ILSS) was investigated according to ASTM
D2344-76 (short beam shear test method). In each case to evaluate the physico-mechanical
properties, five samples were tested and the average valve reported.
Sliding wear frictional properties of the composites were investigated by pin-on-disc machine
according to ASTM D G 99. In this investigation pin was pressed against a rotating disc such
that the contact surface of the pin is flat. The cured composite laminates were cut using a
diamond tipped cutter to yield wear test coupons of size 8mm dia. The test samples were then
glued using an adhesive to pins of size 8mm diameter and 25 mm length. Sliding wear test was
carried out at constant velocity (5 m/s) and for constant sliding distance (1.2 km) at various
normal applied loads viz., 30N, 60N and 90N.
3. RESULTS AND DISCUSSION
3.1. Mechanical Properties
3.1.1. Density
The density of SiO2 filled GE composites lies in the range 2.1369 to 2.2530 g/cc which is slightly
higher than unfilled GE composite density (2.1164 g/cc). This is due to increase in high dense
SiO2 filler content in GE composites.
3.1.2. Surface hardness
In this investigation, slight increase in surface hardness (72HRB-GEC composite to78HRB-
9SGEC composite) due to the addtion of SiO2 fillers in the composites is observed.
3.1.3. Tensile properties
In this investigation, tensile strength, young’s modulus and percentage of elongation at fracture
of SiO2 loaded GE composites of five samples in each type are tested and average results were
plotted is as shown in Figure 1(a)-(d). Figure 1(a) shows the tensile load versus elongation
behavior of SiO2 filled and unfilled GE composites. It is observed that, the 3SGE, 6SGE and
9SGE specimens exhibits higher young’s modulus, lower percentage of elongation and lower
tensile strength compared to GE specimens. As the filler content increases in the GE composites,

Vol.8, No.7 Influence of SiO2 Fillers on Sliding Wear Resistance and Mechanical Properties 517
the Young’s modulus increases and decreases the tensile strength and elongation. The unfilled
GE composite exhibits highest tensile strength (322 Mpa), lowest young modulus (6708 Mpa),
further due to addition of fillers at 3,6 and 9 wt % reduces the tensile strength to 280, 273 and
237 Mpa and increases the young’s modulus to 7865,8639 and 9713 Mpa respectively. The
elongation reduces from unfilled GE composites of 4.8% to 2.44% of 9 wt % SiO2 filled GE
composite. This indicates that the composites property changes from ductile to tough and rigid,
due to addition of SiO2 particles in glass epoxy composite. The toughness and rigidness of the
composite increased with increase in content of SiO2 particles in the composite. Also the 9SGE
specimen exhibits lowest tensile strength compared to other specimens may be due to
agglomeration of fillers in the resin at higher percentage of fillers.
3.1.4. Flexural properties
Due to the of addition of SiO2 particles in GE composites flexural strength increase, unfilled
GE composites exhibits lowest flexural strength of 365 Mpa, 3 wt% and 6 wt% SiO2 particles
filled GE composites exhibits highest flexural strength 401 and 406 Mpa. Further increase in
addition of filler reduces the flexural strength to 387 Mpa (9wt% of filler content composite).
However, addition of filler content in glass epoxy composite increases the flexural strength.
3.1.5. Interlaminar shear strength
Observed from the short beam technique, the interlaminar shear strength (ILSS) of SiO2 particles
filled GE composites higher than unfilled GE composite. ILSS increases from 9.8 Mpa of
unfilled GE composite to 11 Mpa of 6 wt % SiO2 particles filled GE composite. Further increase
in content of SiO2 particles in GE composites decreases the ILSS
3.1.6. Impact strength
By the result of izod impact test, it was observed that the energy obsorbed by the composite
decreases from 0.1633 J/mm in unfilled GE composite to 0.08J/mm in 9 wt% SiO2 filled GE
composite is shown in Figure 1(f).
In fact it was verified experimentally by several research groups all over the world, that micro
particle of metallic or inorganic type prove the ability to reinforce effectively thermoplastic and
also thermosetting polymer matrices and improves the mechanical properties. But the
improvement depends on filler volume content. The quality of the interface in composites, i.e.
the static adhesion strength as well as the interfacial stiffness, usually plays a very important role
in the materials capability to transfer stresses and elastic deformation from the matrix to the
filler. If filler interaction is poor, the particles are unable to carry any part of the external load, in
that case the strength of the composite lower. If the bonding between the fillers and matrix is

518 B. Shivamurthy, Siddaramaiah and M.S. Prabhuswamy Vol.8, No.7
instead strong enough, the effective load and deformation transfer takes place between the matrix
and filler improves the strength. But another important fact that, the bonding between fillers and
matrix more related to dispersion state of the particles in the matrix phase.
Figure1. Plots of mechanical properties of SiO2 filler filled and unfilled GE composites (a)
tensile load versus elongation, (b) tensile strength, (c) young’s modulus, (d) elongation at break,
(e) flexural strenght and (f) impact strength.
a
b
c d
e f

Vol.8, No.7 Influence of SiO2 Fillers on Sliding Wear Resistance and Mechanical Properties 519
In the present investigation at 3 wt% and 6wt% of filler loaded GE composites exhibits higher
flexural and ILSS and higher young’s modulus compared to unfilled GE composites. Further
increase in filler content (as in the case of 9 wt% filler loaded composite) reduces the flexural
and ILS Strength. This is due to the poor matrix and filler interface which was due to
agglomeration of SiO2 particles at higher percentage of loading. This agglomerate would remain
in the matrix and stress concentration locally and easily induce the initiation of the final failure.
By the result of izod impact test, it was observed that the impact strength decreases with
increased addition of fillers in GE composites. This is due to embrittling effects occur at higher
filler contents, where more agglomerates are likely to be found. Higher impact strength at lower
filler contents on the other hand justifies lower stress concentrations. As toughened epoxy resin
matrics classified as brittle materials, addition of SiO2 fillers dominates the brittleproperty in the
GE composite but also increases the toughness of the composite which is exibits in the tensile
test results.
The correlation of flexural strength with tensile strength of woven fabric glass epoxy composite
was investigated by many researchers. Whitney [36] developed an eqvation σuf = 1.52σut for
glass epoxy composite and σuf = 1.33σut for carbon epoxy composite. This equation was verified
by Bullock [37] and Whitney et al [38] by experiment results and proved the same. In present
investigation, the results obtained by tensile and flexural strength proves the above relations
verymuch better in SiO2 particulate filled GE compsoites than unfilled GE composites.
3.2. Sliding Wear Studies
3.2.1. Sliding wear loss
Figure 2 shows the wear loss of unfilled GE and SiO2 particulate filled GE composites for
different loads of 30N, 60N and 90N. It is evident from the figure2 that irrespective of the type
of sample used; there is an increase in wear loss with increase of normal applied load. The
unfilled GE composite exhibited considerably higher wear loss of 0.0095g than SiO2 particle
filled glass epoxy composites. By increasing the load from 30 to 90N, the wear loss of unfilled
GE composite has increased from 0.0015g to 0.0095g, which is higher as compared to 3SGEC
which has wear loss increased from 0.0011g to 0.0066g at same range of applied load. The
highest wear loss of 0.0076g and 0.0089g is seen in 9SGE at loads of 30N and 60N. But the wear
loss in unfilled glass epoxy composite is seen lowest at lower loads and highest at higher loads
compared to other type of composite. This indicates that unfilled GE composite wear loss is
more sensitive with respect to normal applied load. Whereas, in case of SiO2 particle filled glass
epoxy composites particularly 6SGE and 9SGE composites, the wear loss is less load dependent
compared to 3SGE composite and unfilled glass epoxy composite. This indicates the higher
percentage fillers in the composite helps in increasing the wear resistance at higher loads.

520 B. Shivamurthy, Siddaramaiah and M.S. Prabhuswamy Vol.8, No.7
However, as per the results plotted in the Figure 2, the 3SGE composite shows better wear
resistance at 30N and 60N loads compared to all other types of composites and 6SGE composite
exhibits better wear performance at higher load. But it is also is observed from the
experimentation, that severe wear takes place due to catastrophic fracture and dislodging of SiO2
particles from the upper surface of the composite specimen as soon as composite specimen pin
come in contact with the wear disc at lower loads. The wear loss effect due to this phenomenon
increases with increase in content of fillers. But high filler content composite exhibits steady
wear loss after reaching a steady wear situation as shown in Figure 2. Higher wear loss is
observed in 9SGE composite due to weak in matrix reinforcement and filler interaction. This
result is supported by decreased flexural strength, tensile strength and impact strength.
Figure 2. Plot of wear loss versus normal load of unfilled and SiO2 particulate filled composites.
3.2.2. Specific wear rate
The result of specific wear rate of unfilled GE and SiO2 filled composites for an abrading
distance of 1.2 km at different loads (30N, 60N and 90N) with a constant sliding velocity 5m/s is
as shown in Figure 3 and values are tabulated in Table 2. It is observed that the specific wear rate
decreases with increase in applied normal load in case of 6SGE and 9SGE composites and
increases with increase in applied load in case of unfilled GE composite and 3SGE composite.
The 3SGE composite shows lowest specific wear rate than other composite at 30 and 60N load.
The 6SGE composite shows lowest specific wear rate at higher load. Due to addition of SiO2
filler in the composite, low specific wear rate exhibits at higher loads in case of 3SGE and 6SGE
composite. But in case of 9SGEC, due addition of more filler leads to agglomeration, this
reduces matrix and reinforcement filler interaction due to less adhesion.
Unfilled GE composite exhibits the highest specific wear rate of 4.1x10-8 g/N-m, 7.98 x10-8 g/N-
m and 8.75x10-8 g/N-m at applied normal loads of 30N, 60N and 90N respectively. The lowest
specific wear rate is observed as 3.0x10-8 g/N-m, 4.70 x10-8 g/N-m and 6.1x10-8 g/N-m at

Vol.8, No.7 Influence of SiO2 Fillers on Sliding Wear Resistance and Mechanical Properties 521
applied normal loads 30N, 60N and 90N respectively. In the case of 6SGcomposites it exhibits
specific wear rate of 9.10 x10-8 g/N-m and 2.11 x10-7 g/N-m at loads 30N, 60N respectively and
for 9SGE it exhibits 5.00 x10-8 g/N-m and 1.11 x10-7 g/N-m at applied normal loads 30N, 60N
respectively, which is more than specific wear rates of GE composite and more than 3SGE
composites at the same range of load. Hence, at 30 to 60N 3SGE composite shows better result.
From this it is evident that the wear resistance of glass epoxy composite increases with increase
in filler content up to 3wt%. 3wt% till 6 wt% reduces the wear resistance and increases the
specific wear rate slightly. Further increase in filler content beyond 6wt% reduces the wear
resistance and increases the specific wear rate significantly. This is attributed to the fact that, in
3wt % filled glass epoxy composite, the dispersion of filler is uniform and better adhesion
between the matrix and filler and reinforcement. Where as due to higher content of filler in
6SGE and 9SGE composites, may be poor adhesion results higher wear rate. Also it is observed
that in unfilled GE composites and 3SGE composites, specific wear increases with increase in
load where as the specific wear rate in both 6SGE and 9SGE composites exhibits decrease in
wear rate with increase in load. This indicates a steady wear loss is observed at higher percent of
filler loaded composite compared to unfilled and low percent filler loaded composites. This is
very much important in selecting and designing long life of component with tolerable wear limit.
Table 2. Specific wear rate (g / N-m) and (σe)-1 factor of unfilled and SiO2 particles filled glass
epoxy composites.
Load Type of composite
GEC 3SGEC 6SGEC 9SGEC
30N 4.1E-08 3.00E-08 9.10E-08 2.11E-07
60N 7.9E-08 4.70E-08 5.00E-08 1.11E-07
90N 8.7E-08 6.10E-08 4.00E-08 8.20E-08
(σe)-1 0.0647 0.1003 0.1159 0.1729
Figure 3. Plot of Specific wear rate versus type of composites

522 B. Shivamurthy, Siddaramaiah and M.S. Prabhuswamy Vol.8, No.7
Many researcher developed different models to analyze the wear of polymer composite
materials. Viswanath et al [39] developed an empirical equation for the wear of polymers, in that
wear equation, the volume loss of polymer material while sliding on a pin-on-disc machine is
expressed in terms of the operating conditions, material properties and counter surface
roughness. Both linear and non linear relationships of volume loss with other variables are
considered in evaluating dimensionless wear coefficient.
The correlations of wear loss with selected mechanical properties such as (σe) factor (where, σ is
the ultimate tensile strength and e is the ultimate elongation), hardness (H) have been reported in
single-pass studies of polymer composites [40, 41]. Lancaster [47] stated that the product of σ
and e is a very important factor which controls the abrasive wear behavior of composite.
Generally fibers / filler reinforcement increases the tensile strength (σ) of neat polymer, they
decrease the ultimate elongation (e) and hence the product (σ e) may become smaller than that of
neat polymer. Hence, reinforcement usually leads deterioration in the abrasive wear resistance.
The model proposed by Ratner et al. [41] states that rate of material removal is inversely
proportional to the product of stress and strain at rupture.
Poomali et al [42] conducted studies on mechanical and wear behavior of PMMA/TPU blends.
In there work neat PMMA and 95/5 PMMA/TPU blend wear volume loss decreased with
increase in σe factor. But increase of TPU grater than 5% in PMMA showed increase in the wear
volume loss even though the factor σe is increasing.
Suresh et al [43] carried out wear study to determine the effect of glass fiber content on wear
behavior of polyurethane composite. The relation between specific wear rate and (σe)-1 was
studied, no linear trend was observed.
In the present work, specific wear rate decreases with increase of (σe)-1valve up to 3wt% of filler
content. Further increase of filler content > 6wt%, the specific wear rate increases with increase
in (σe)-1 value of the composite and it fallows the Ratner statement [41]. Hence it is clear from
the above discussion that 3wt% filler content gives better wear resistance because of optimum
mechanical property (highest modulus and lowest (σe)-1 factor compared to other composites) of
the composites. This is achieved by the good interface between filler and matrix.
3.3. Coefficient of Friction
Coefficient of friction decreases with increase in load in all types of SiO2 particulate filled GE
composites and unfilled GE composites as shown in Figure 4 and Table 4. The 3 wt% SiO2
particulate filled GE composite exhibits highest coefficient of friction and 6 wt% SiO2 particulate
filled GE composite exhibits very low coefficient of friction for all loads. More fluctuation of
coefficient of friction is observed for the same loads in SiO2 particulate filled composite due to

Vol.8, No.7 Influence of SiO2 Fillers on Sliding Wear Resistance and Mechanical Properties 523
dislodging of SiO2 particle from the specimen surface and traps in between specimen and
abrading metal counter plate surface.
Table 4. Coefficient of friction of unfilled and SiO2 particles filled glass epoxy composites.
Load Type of composite
GEC 3SGEC 6SGEC 9SGEC
30N 0.456 0.528 0.422 0.484
60N 0.397 0.51 0.404 0.413
90N 0.317 0.4 0.317 0.366
Figure 4. Plot of coefficient of friction at different loads of unfilled and SiO2 particulate filled
composites
SEM photomicrographs of unfilled GE composite worn surface at 30N, 60N and 90N (at a
constant sliding velocity 5m/s and constant sliding distance of 1200m) is as shown in Figure 5
(a), (b) and (c) respectively. From these photomicrographs it is observed that at 30N load matrix
wear is more predominant than fiber in the composite. Also it was observed the matrix and fiber
wear in the composite at load 60N as shown in Figure 5(b). Further increased in load to 90N,
severe damages to the fibers and matrix observed (Figure 5(c)).
Surface morphology

524 B. Shivamurthy, Siddaramaiah and M.S. Prabhuswamy Vol.8, No.7
Figure 6 shows the SEM photomicrographs of worn surface of 3wt % SiO2 particulate filled GE
composite. At 30N load only the part of matrix removed and no fiber damage is observed and
fiber also not visible due to hidden in the matrix (represented in Figure (a)) and fillers. At 60N
load a portion of fibers observed and not in full, due to wear, the interface bonded matrix
removed from the fibers. But at 90N load observed more number of fibers in the
photomicrograph and damaged fibers which are representing like discontinued lines as presented
in Figure 6(c). Also interface matrix detached from the fiber surface observed in case of applied
load 90N.
Figure 5. Worn surface SEM photographs of unfilled GE composite at load; (a) 30N, (b) 60N
and (c) 90N
Worn surface SEM photographs of 6SGE composite at load 30N, 60N and at 90N are as shown
in Figure 7 (a), (b) and (c) respectively. At 30N load only the portion of matrix removed and no
fiber damage is observed, at higher loads (> 60N) fiber damage observed but the surface damage
a b
c

Vol.8, No.7 Influence of SiO2 Fillers on Sliding Wear Resistance and Mechanical Properties 525
severity in Figure 7(b) and (c) is not much difference. Also the wear is steady in this case
according to the test data. SEM studies support the wear behavior of these composites.
Fig. 6. Worn surface SEM photographs of 3SGE composite at load, (a) 30N, (b) 60N, (c) 90N
Figure 8 shows the worn surface SEM photographs of 9SGE composite at load 30N, 60N and
90N. From the figure it was noticed that matrix and reinforcement fracture almost steady type of
wear. Due to higher content of filler, the poor interface between matrix, reinforcement and fillers
results higher wear loss. But higher content of filler also responsible for steady wear rate.
a b
c

526 B. Shivamurthy, Siddaramaiah and M.S. Prabhuswamy Vol.8, No.7
Figure 7. Worn surface SEM photomicrographs of 6SGE composite at load; (a) 30N, (b) 60N,
and (c) 90N
4. CONCLUSIONS
The following are the salient observation made from the above investigation
 Increase in filler content in the GE composite enhances the young’s modulus, flexural
strength, surface hardness, brittleness and decreases the tensile strength and elongation at
break.
 SiO2 particulate filled GE composites tensile strength and flexural strength follows very
near the relation σuf = 1.52σut when compared to unfilled GE composites.
 The interlaminar shear strength improved after incorporation of fillers, 6 wt% SiO2 filler
content GE composites exhibits maximum inter laminar shear strength (11 Mpa).
 Unfilled GE composite and 3wt% SiO2 particulate filled GE composite sliding wear loss
and specific wear rate strongly influenced by the applied load as compared to other GE
composites.
a b
c

Vol.8, No.7 Influence of SiO2 Fillers on Sliding Wear Resistance and Mechanical Properties 527
 The 3 and 6 wt% of SiO2 particulate filled GE composites exhibits good performance in
flexural and sliding wear resistance. Further increase in filler loading was not beneficial
to flexural and sliding wear performance.
 The 6 and 9 wt % of SiO2 particulate filled composite exhibits steady wear rate.
Figure 8. Worn surface SEM photographs of 9SGE composite at load; (a) 30N, (b) 60N and (c)
90N
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