PAPER PUBLICATION THE EFFECT OF REACTANT COMPOSITIONS ON THE The Effect Of Reactant Compositions On The Microstructure Of Ceramic Materials Formed By Combustion Synthesis.
PAPER PUBLICATION
THE EFFECT OF REACTANT COMPOSITIONS ON THE
MICROSTRUCTURE OF CERAMIC MATERIALS FORMED BY
COMBUSTION SYNTHESIS
RAMZUL IRHAM RIZA
D 200102010
MECHANICAL ENGINEERING DEPARTMENT
INTERNATIONAL PROGRAM
IN AUTOMOTIVE/MOTORCYCLE ENGINEERING
MUHAMMADIYAH UNIVERSITY OF SURAKARTA
2014
APPROVAL
The paper publication entitles "THE EFFECT oF REAGTANT coMpoStTtONS
ON THE
MICROSTRUCTURE
COMBUSTION SYNTHESIS",
OF CERAMIC MATERIALS FORMED BY
has been approved by supervisor and
authorized by Director of lnternational Program as partial fulfillment of the
requirements for getting the Bachelor Degree of Engineering in Automotive
Department of Muhammadiyah University of Surakarta.
Written by:
Name
NIM
: Ramzul lrham Riza
: D 20MA2M0
Has Approved and legalized on:
Day
Date
:3"t1'rn.lrrj
: \? Dec,E*tber
2o\4
(Wijianto,ST,M.Eng.Sc)
(Dr. Tri Widodo Besar Riyadi)
Admitted by,
(Wijianto,ST,M.Eng.Sc)
THE EFFECT OF REACTANT COMPOSITIONS ON THE MICROSTRUCTURE
OF CERAMIC MATERIALS FORMED BY COMBUSTION SYNTHESIS
Ramzul Irham Riza
Mechanical Engineering Department
Universitas Muhammadiyah Surakarta
Jl. Ahmad Yani Tromol Pos I Pabelan Kartasura Surakarta 57102
Email: [email protected]
ABSTRACT
Ceramics have been attractive as advance materials for high temperature
applications due to their advantages such as high modulus, high hardness, high
melting temperature, and high corrosion resistance. Of a broad range of ceramics,
titanium carbide and aluminide have developed into one of the most interesting
ceramics since they have high strength and good wear resistance at elevated
ceramic materials. Producing TiC-Al2O3 from economical material (TiO2) is less
expensive than that from their elemental powders. The combustion synthesis (CS)
process offers significant advantages to fabricate TiC-Al2O3 since it produces high
exothermic reaction and takes a short processing time. The objective of this study
was to explore the combustion synthesis of TiC-Al2O3 and investigate the effect of
reactant compositions on the combustion process and microstructure of synthesized
products. The combustion synthesis was carried out in a combustion chamber with
an atmospheric condition. The ignition technique to initiate the CS was performed
using an arc flame. The microstructure and mechanical properties of synthesized
products were observed. The result of this research would benefit for producing a
high performance ceramic material obtained from economical material with an
efficient process.
Keywords: Ceramics, TiC-Al2O3, TiO2, Combustion synthesis, Arc flame,
Microstructure
INTRODUCTION
Background of the Study
There has been a lot of interest in ceramic materials such as TiC, TiB2, WC, SiC, and
Al2O3 as hard protective coatings in a wide range of industrial applications since they have high
hardness and high wear resistance (B. Huang, L. D. Chen, and S. Q. Bai,, 2006)(B. G. Kim, Y.
Choi, J. W. Lee, Y. W. Lee, and G. M. Kim, 2000)(D. Vallauri and I. C , 2008)(M. Razavi, M.
Reza, and R. Mansoori, 2008). Of these materials, titanium carbide has developed into the most
interesting ceramic for high temperature application due to its high modulus, high hardness, high
melting temperature, and high corrosion resistance(D. Vallauri and I. C , 2008). However, the
application of single phase ceramic in high temperature is limited due to its poor fracture
toughness. Therefore, the TiC particle has been widely investigated as a candidate for use in the
reinforcing phase for various composite materials such as metallic matrix composite(S. C. Tjong
and Z. Y. Ma, 2000), intermetallic matrix composite, and ceramic matrix composite(C. L. Yeh
and Y. L. Chen, 2008).
Alumina ceramic systems such as TiC–Al2O3 have also been widely found in high
temperature applications since they have high hardness and low density. It was also reported
that the binary ceramic composites of TiC–Al2O3 could improve the fracture toughness of the
individual ceramic materials, either TiC or Al2O3. Further investigations have showed that ternary
ceramic composites exhibited higher fracture toughness than those of binary ceramic
composites. The addition of 10 % ZrO2 into Al2O3–TiC prepared from TiO2, Al, and C using
combustion synthesis and followed by hot pressing was able to increase the fracture toughness
of Al2O3–TiC–10 wt.% ZrO2 by approximately 20% more than that of Al2O3–TiC composite(Q.
Dong, Q. Tang, and W. Li, 2008).
Objectives of the Study
Based on the background and statement of the problem in this final project, the object of
this research is as followed:
1. To produce ceramic materials by combustion synthesis process
2. To observe the microstructure of synthesized product
1
Problem Limitations
To avoid problem expaditure is needed some of problem limitations so that it can be more
understable by focusing on those problem. Those problems are:
1. The material to produce ceramics are TiO2,C and Al.
2. Combustion process is done by using arc welding.
3. Testing material is tested by SEM and XRD machine.
2
REVIEW OF LITERATURE
Literature Study
There are some literatures as the references of this research. Those are the
researches about ceramic material and combustion synthesis. Titanium carbide has
developed into the most interesting ceramic for high temperature application due to its high
modulus, high hardness, high melting temperature, and high corrosion resistance ( D.Vallauri
and I.C ,2008)
Ceramic processing generally involves high temperatures, and the resulting materials are
heat resistant or refractory (J. J. Moore and H. J. Feng,1995 )
The work part after compaction is called a green compact or simply a green, the word
green meaning not yet fully processed (Arvind Varma, Alexander S. Rogachev', Alexander S.
Mukasyan,1998 )
The reactant is visualized as being composed of a large number of highly dense,spherical
grains (S Das, A K Mukhophadiyay, S Datta and D Basu, 2009 )
Reducing the effects of gravity during synthesis can inhibit segregation of phases with
different densities. Some experiments have been conducted in Lear jet planes to obtain dense
ceramic-metal composites (e.g., TiC-Al2O3-A1,T iB2-Al2O3-A1Z, rB2-Al2O3-A1,B4CAl2O3-A1) in
thermite-type systems (John Wiley & Sons, 1998 )
3
FUNDAMENTAL THEORY
Ceramics
Ceramics are defined as a class of inorganic, nonmetallic solids that are subjected to
high temperature in manufacture and/or use. The most common ceramics are composed of
oxides, carbides, and nitrides. Silicides, borides, phosphides, tellurides, and selenides also are
used to produce ceramics. Ceramic processing generally involves high temperatures, and the
resulting materials are heat resistant or refractory.
Ceramics are usually made by heating natural clays at a high temperature. Typically,
clays for ceramics are grouped into two general types: red clay, which contains primarily silicon
dioxide and iron oxide; and kaolin clay, which contains mostly aluminum oxide and almost no
iron oxide. Because red clay contains more iron, it often has a rusty brown shade somewhere
between light tan and dark brown, while pure kaolin clay is white.
Combustion Synthesis
Combustion syntesis is a process to synthesize materials which use highly exothermic
chemical reactions between metals and non metals, the metathetical (exchange) reaction
between reactive compounds or reactions involves compounds/mixtures.
There are two kinds of
combustion synthesis,namely Self-Ppropagating High
Temperature Synthesis (SHS) and Volume Combustion Synthesis (VCS). In both cases,
reactants may be pressed into a pellet, typically cylindrical in shape. The samples are then
heated by an external source (e.g., tungsten coil, laser) either locally (SHS) or uniformly (VCS)
to initiate an exothermic reaction.
4
Figure 1 a) SHS Ilustrations b) VCS Ilustrations
Ignition Techniques
The ECAS process is schematically shown in Figure 2.2. It simultaneously applies an
electric current along with a mechanical pressure in order to consolidate powders or synthesize
and simultaneously densify specific products with desired configuration and density. The applied
electric current and mechanical load may be constant throughout the sintering cycle or may vary
during the selected densification stages. In particular, the current may be adjusted by an
automatic controller so that a prescribed temperature cycle is followed.
5
Figure 2 ECAS Scheme
Green Mixture Density
Mixtured powder material are pressed in dies under high pressure to form them into the
required shape. The work part after compaction is called a green compact or simply a green, the
word green meaning not yet fully processed(Marinov).
As a result of compaction, the density of the part, called the green density is much
greater than the starting material density, but is not uniform in the green(Marinov)
Reactant gas undergoes mass transfer from the bulk gas stream to the pellet surface.
From the surface the gas must diffuse to arrive at a sharp interface between the grain particle
and the product layer for reaction to take place(Li, 2003).
Grain Size of Powder
Grain size influences many properties of particulate materials and is a valuable indicator
of quality and performance. This is true for powders, suspensions, emulsions, and aerosols. The
size and shape of powders influences flow and compaction properties. Smaller particles dissolve
more quickly and lead to higher suspension viscosities than larger ones. Smaller droplet sizes
6
and higher surface charge (zeta potential) will typically improve suspension and emulsion
stability.
Figure 3 Ti Powder grain size
7
METHODOLOGY OF PROJECT
Flow Chart of Project
Figure 4. Flow chart of project
8
Material
The powders were used in this work are aluminium (Al), titanium oxide (TiO2), carbon black (C)
and alumina (Al2O3).
Figure 5. TiO2 Powder
Figure 6. Al Powder
9
Figure 7. C Powder
Tools
1. Ohaus Advanturer Balance
Figure 8. Balance
10
2. Torque Wrench
Figure 9. Torque Wrench
3. Dies and Punch
Figure 10. Dies
11
4. Arch Welding Inverter
Figure 4. Arch Welding Inverter
12
RESULT and DISCUSSION
.
1. Synthesized Product
Pure material is a sample material composed of TiO2, Al, C with ratio of 3 : 4 : 3, without any
excess. After the sample is ignited using arch flame, we can observe the flame propagation on
its sample is very quick among all of sample. When material begins to react, its flashing can be
seen clearly.
Figure 12. Synthesized Product without Excess Addition
The sample with 20% exess material is a sample by adding 20% TiO2 and C so that it
has different number of mass material. On this process, the flame propagation of combusting
synthesis is not too much different with pure material. The flame propagation is still quick but not
as rapid as pure material.
13
Figure13. Synthesized Product with 20% Excess addtion
The mass of the sample is 1.288 gram or the sample with 40 % excess of TiO2 and C. In
this excess the flame propagation is starting slow when combusting process was conducted.
Flashing is appeared which means that material begins to react.
Figure 14. Synthesized Product with 40 % Excess
14
In 60 % Excess of TIO2 and C, it has slower flame propagation than before experiments
and there is flashing when the material start to react. The results of this experiment is solid
material can not be formed well because at half side of its material still in powder apperances.
Figure 55. Syntheesized Product with 60 % Excess
At 80% excess of TiO2 and C with the total mass material is 1.575 gram.The combustion
process cannot be done well since only small part of sample can be combusted.
15
Figure 66. Synthesized Product with 80 % Excess
Total mass material in this sample is 1.719 gram or 100% excess of TiO2 and C. At this
section the material cannot fine react during combustion process. The flame propagation does
not exist.
Figure 7. Synthesized Product with 100% Excess
16
2. XRD Pattern
XRD pure material result is a result of XRD in pure sample material without any excess
addition of stoichiometric compositions.
The XRD pattern of pure material describes that there is only two TiC detected by XRD
testing which is at approximately 45 in theta with 5 in intensity or counts and 80 in theta with 8 in
counts. Meanwhile, Al2O3 are detected as 6 points, namely at 31,37, 39, 45, 60, and 85 in 2
theta.
Figure 88. XRD Pattern without Excess
This is a result of XRD testing material with 20 % excess of TiO 2 and C. It can be
observed that TiC with 20% excess of TiO2 and C has increased from only one point become 3
points,they are at 35, 41 and 72 theta. There are seven of Al2O3 detected in this sample. Those
are at 19, 31, 37, 45, 60, 67 and 87 in 2 theta and the intensities are 9, 5, 23, 7, 7, 4 and 7.
17
Figure 9. XRD Pattern with 20 % Excess
18
This is last sample which is tested by XRD,40 % excess of TiO2 and C. Basically,for the 3rd
experimental,it has almost
same theta with the 2nd experiment but it has additional TiC
detected at 60 and 78 in 2 theta.
Figure 20. XRD Pattern With 40% Excess
3. Microsructures
It can be observed that the particle is heterogeneous in the shape and size. Some particles
show the shape like denrite, and others form a cubic shape. The Differences of Microstuctures
can be seen in Figure 21 to 23.
19
Figure 10. SEM Figure of Without Excess Synthesized Product
20
Figure 11. SEM Figure of With 20 % Excess
21
Figure 23. SEM Figure of With 20 % Excess
22
CONCLUSION AND SUGGESTIONS
Conclusions
Based on analysis and discussion above, there are some conclusions which can be
drawn as follows:
a. The production of ceramic material using combustion synthesis was succesful. The effect of
reactant composition has influenced the ignition and flame propagation.
b. The phase composition of the synthesized product can be detected using SEM and XRD.
Al2O3 can be clealry seen from the XRD pattern. However, XRD spectra of titanium caribide
(TiC) as one of product from combustion process does not appear. The effect of reactant
composition on the microstructure of the synthesized product can be observed from the
porosity of the reacted product, in which the increasing content of TiO 2 and C resulted in the
increase of porosity. The increasing content of TiO2 and C can also be identifued from the
XRD pattern. The more excess addition the higher peak result on XRD test.
Suggestions
From the experiment that has been done by researcher, there are several things that
need to be understood well in combustion process research,they are :
a. TiC cannot be observed in the reacted product. This is due to small size of TiC itself.
b. Combution process should be done in inside of a box to minimalize contact with oxygen
c. Balancing process should be done carefully by using mask because the powder grain is
very small and is not good to respiration.
23
REFERENCES
1. Bulk ultrafine binderless WC prepared by spark plasma sintering. B. Huang, L. D. Chen, and S. Q. Bai,.
2006, Scripta Materialia, Vol. 54, pp. 441–445.
2. Characterization of a silicon carbide thin layer prepared by a self-propagating high temperature
synthesis reaction. B. G. Kim, Y. Choi, J. W. Lee, Y. W. Lee, and G. M. Kim. 2000, Thin Solid Films, pp.
82–86.
3. TiC–TiB2 composites: A review of phase relationships, processing and properties. D. Vallauri and I. C .
2008, Journal of the European Ceramic Society, Vol. 28, pp. 1697–1713.
4. Synthesis of TiC–Al2O3 nanocomposite powder from impure Ti chips, Al and carbon black by
mechanical alloying , . M. Razavi, M. Reza, and R. Mansoori. 2008, Journal of Alloys and Compounds,
Vol. 450, pp. 463–467.
5. Microstructural and mechanical characteristics of in situ metal matrix composites . S. C. Tjong and Z. Y.
Ma. July 2000, Materials Science and Engineering, Vol. 29, pp. 49–113.
6. Combustion synthesis of TiC–TiB2 composites. C. L. Yeh and Y. L. Chen. August 2008, Journal of Alloys
and Compounds, Vol. 463, pp. 373–377.
7. TiC–NiAl composites obtained by SHS: a time-resolved XRD study. M. A. C. Curfs, I.G. Cano, G.B.M.
Vaughan, X. Turrillas, A. Kvick, Rodrıgues. 2002, Journal of the European Ceramic Society, Vol. 22, pp.
1039–1044.
8. Synthesis of NiAl–TiC nanocomposite by mechanical alloying elemental powders. L. Z. Zhou, J. T. Guo,
and G. J. Fan. 1–2, Jun 1998, Materials Science and Engineering: A, Vol. 249, pp. 103–108.
9. Combustion synthesis of TiC–NiAl composite by induction heating. X. Zhu, T. Zhang, D. Marchant, and
V. Morris. 13, Oct 2010, Journal of the European Ceramic Society, Vol. 30, pp. 2781–2790.
10. Al2O3–TiC–ZrO2 nanocomposites fabricated by combustion synthesis followed by hot pressing. Q.
Dong, Q. Tang, and W. Li. 1–2, Feb 2008, Materials Science and Engineering: A, Vol. 475, pp. 68–75.
11. Co ustio Pro esses That Sy thesize Materials,” , vol. , o., pp. , . Merzhanov, A. G. s.l. : Elsevier,
1996, Journal of Materials Processing technology, Vol. 56, pp. 222–243.
12. Combustion synthesis of advanced materials: Part I. Reaction parameters . J. J. Moore and H. J. Feng.
4–5, Jan 1995, Progress in Materials Science, Vol. 39, pp. 243–273.
24
13. Kirk-Othmer Encyclopedia Of Chemical Technology. 4th edition. s.l. : John Wiley & Sons. Vol. Volume
5.
14. 1987 Census Of Manufactures. Washington, D.C : U. S. Department of Commerce, May 1990.
15. Ull a ’s E y lopedia Of I dustrial Che istry. 5th Edition. Vol. A6.
16.COMBUSTION SYNTHESIS OF ADVANCED MATERIALS:PRINCIPLES AND APPLICATIONS. s.l. Arvind
Varma, Alexander S. Rogachev', Alexander S. Mukasyan : Department of Chemical Engineering
University of Notre Dame.
17. Prospects of microwave processing: An overview. S DAS*, A K MUKHOPADHYAY, S DATTA and D
BASU. 1, Kolkata : Central Glass and Ceramic Research Institute, February 2009, Vol. 32.
18. Consolidation/synthesis of materials by electric current activated/assisted. Roberto Orru` a,b,
Roberta Licheri , Antonio Mario Locci , Alberto Cincotti , Giacomo Cao. Materials Science and
Engineering R.
19. Powder Metallurgy. Marinov, Valery. Manufacturing Technology.
20. The numerical simulation of the heterogeneous composition effect on the combustion synthesis of
TiB2 compound. Li, H.P. Hsintien : Elsevier Science Ltd, 2003.
21. Processing of Elemental Titanium by Powder Metallurgy Techniques. L. Bolzoni, E.M. Ruiz-Navas and
E. Gordo. Switzerland : Trans Tech Publications, 2013, Materials Science Forum, Vol. 765.
22. An introduction to powder metallurgy. F. Tummler and R. Oberacker. 1993, London: Institute of
Materials.
23. Combustion synthesis of metal-matrix composites: Part I, teh Ti-TiC-Al203 system. J. J. M. A.O.
Kunrath, T.R. Strhaecher. 2, 1996, Scripta Materialia, Vol. 34, pp. 175–181.
24. Combustion synthesis of fine AlN powder and its reaction control. T. Sakurai, O. Yamada, and Y.
Miyamoto. 1–2, Jan 2006, Materials Science and Engineering: A, Vol. 416, pp. 40–44.
25. EFFECT OF MECHANICAL MILLING AND CURRENT INTENSITY ON. Mehra, Praktik D. San Diego : s.n.,
2013.
26. SYNTHESIS AND CHARACTERIZATION OF ALUMINA. Rodica Rogojan. Bucharest : s.n., 2011, Vol. 73.
25
THE EFFECT OF REACTANT COMPOSITIONS ON THE
MICROSTRUCTURE OF CERAMIC MATERIALS FORMED BY
COMBUSTION SYNTHESIS
RAMZUL IRHAM RIZA
D 200102010
MECHANICAL ENGINEERING DEPARTMENT
INTERNATIONAL PROGRAM
IN AUTOMOTIVE/MOTORCYCLE ENGINEERING
MUHAMMADIYAH UNIVERSITY OF SURAKARTA
2014
APPROVAL
The paper publication entitles "THE EFFECT oF REAGTANT coMpoStTtONS
ON THE
MICROSTRUCTURE
COMBUSTION SYNTHESIS",
OF CERAMIC MATERIALS FORMED BY
has been approved by supervisor and
authorized by Director of lnternational Program as partial fulfillment of the
requirements for getting the Bachelor Degree of Engineering in Automotive
Department of Muhammadiyah University of Surakarta.
Written by:
Name
NIM
: Ramzul lrham Riza
: D 20MA2M0
Has Approved and legalized on:
Day
Date
:3"t1'rn.lrrj
: \? Dec,E*tber
2o\4
(Wijianto,ST,M.Eng.Sc)
(Dr. Tri Widodo Besar Riyadi)
Admitted by,
(Wijianto,ST,M.Eng.Sc)
THE EFFECT OF REACTANT COMPOSITIONS ON THE MICROSTRUCTURE
OF CERAMIC MATERIALS FORMED BY COMBUSTION SYNTHESIS
Ramzul Irham Riza
Mechanical Engineering Department
Universitas Muhammadiyah Surakarta
Jl. Ahmad Yani Tromol Pos I Pabelan Kartasura Surakarta 57102
Email: [email protected]
ABSTRACT
Ceramics have been attractive as advance materials for high temperature
applications due to their advantages such as high modulus, high hardness, high
melting temperature, and high corrosion resistance. Of a broad range of ceramics,
titanium carbide and aluminide have developed into one of the most interesting
ceramics since they have high strength and good wear resistance at elevated
ceramic materials. Producing TiC-Al2O3 from economical material (TiO2) is less
expensive than that from their elemental powders. The combustion synthesis (CS)
process offers significant advantages to fabricate TiC-Al2O3 since it produces high
exothermic reaction and takes a short processing time. The objective of this study
was to explore the combustion synthesis of TiC-Al2O3 and investigate the effect of
reactant compositions on the combustion process and microstructure of synthesized
products. The combustion synthesis was carried out in a combustion chamber with
an atmospheric condition. The ignition technique to initiate the CS was performed
using an arc flame. The microstructure and mechanical properties of synthesized
products were observed. The result of this research would benefit for producing a
high performance ceramic material obtained from economical material with an
efficient process.
Keywords: Ceramics, TiC-Al2O3, TiO2, Combustion synthesis, Arc flame,
Microstructure
INTRODUCTION
Background of the Study
There has been a lot of interest in ceramic materials such as TiC, TiB2, WC, SiC, and
Al2O3 as hard protective coatings in a wide range of industrial applications since they have high
hardness and high wear resistance (B. Huang, L. D. Chen, and S. Q. Bai,, 2006)(B. G. Kim, Y.
Choi, J. W. Lee, Y. W. Lee, and G. M. Kim, 2000)(D. Vallauri and I. C , 2008)(M. Razavi, M.
Reza, and R. Mansoori, 2008). Of these materials, titanium carbide has developed into the most
interesting ceramic for high temperature application due to its high modulus, high hardness, high
melting temperature, and high corrosion resistance(D. Vallauri and I. C , 2008). However, the
application of single phase ceramic in high temperature is limited due to its poor fracture
toughness. Therefore, the TiC particle has been widely investigated as a candidate for use in the
reinforcing phase for various composite materials such as metallic matrix composite(S. C. Tjong
and Z. Y. Ma, 2000), intermetallic matrix composite, and ceramic matrix composite(C. L. Yeh
and Y. L. Chen, 2008).
Alumina ceramic systems such as TiC–Al2O3 have also been widely found in high
temperature applications since they have high hardness and low density. It was also reported
that the binary ceramic composites of TiC–Al2O3 could improve the fracture toughness of the
individual ceramic materials, either TiC or Al2O3. Further investigations have showed that ternary
ceramic composites exhibited higher fracture toughness than those of binary ceramic
composites. The addition of 10 % ZrO2 into Al2O3–TiC prepared from TiO2, Al, and C using
combustion synthesis and followed by hot pressing was able to increase the fracture toughness
of Al2O3–TiC–10 wt.% ZrO2 by approximately 20% more than that of Al2O3–TiC composite(Q.
Dong, Q. Tang, and W. Li, 2008).
Objectives of the Study
Based on the background and statement of the problem in this final project, the object of
this research is as followed:
1. To produce ceramic materials by combustion synthesis process
2. To observe the microstructure of synthesized product
1
Problem Limitations
To avoid problem expaditure is needed some of problem limitations so that it can be more
understable by focusing on those problem. Those problems are:
1. The material to produce ceramics are TiO2,C and Al.
2. Combustion process is done by using arc welding.
3. Testing material is tested by SEM and XRD machine.
2
REVIEW OF LITERATURE
Literature Study
There are some literatures as the references of this research. Those are the
researches about ceramic material and combustion synthesis. Titanium carbide has
developed into the most interesting ceramic for high temperature application due to its high
modulus, high hardness, high melting temperature, and high corrosion resistance ( D.Vallauri
and I.C ,2008)
Ceramic processing generally involves high temperatures, and the resulting materials are
heat resistant or refractory (J. J. Moore and H. J. Feng,1995 )
The work part after compaction is called a green compact or simply a green, the word
green meaning not yet fully processed (Arvind Varma, Alexander S. Rogachev', Alexander S.
Mukasyan,1998 )
The reactant is visualized as being composed of a large number of highly dense,spherical
grains (S Das, A K Mukhophadiyay, S Datta and D Basu, 2009 )
Reducing the effects of gravity during synthesis can inhibit segregation of phases with
different densities. Some experiments have been conducted in Lear jet planes to obtain dense
ceramic-metal composites (e.g., TiC-Al2O3-A1,T iB2-Al2O3-A1Z, rB2-Al2O3-A1,B4CAl2O3-A1) in
thermite-type systems (John Wiley & Sons, 1998 )
3
FUNDAMENTAL THEORY
Ceramics
Ceramics are defined as a class of inorganic, nonmetallic solids that are subjected to
high temperature in manufacture and/or use. The most common ceramics are composed of
oxides, carbides, and nitrides. Silicides, borides, phosphides, tellurides, and selenides also are
used to produce ceramics. Ceramic processing generally involves high temperatures, and the
resulting materials are heat resistant or refractory.
Ceramics are usually made by heating natural clays at a high temperature. Typically,
clays for ceramics are grouped into two general types: red clay, which contains primarily silicon
dioxide and iron oxide; and kaolin clay, which contains mostly aluminum oxide and almost no
iron oxide. Because red clay contains more iron, it often has a rusty brown shade somewhere
between light tan and dark brown, while pure kaolin clay is white.
Combustion Synthesis
Combustion syntesis is a process to synthesize materials which use highly exothermic
chemical reactions between metals and non metals, the metathetical (exchange) reaction
between reactive compounds or reactions involves compounds/mixtures.
There are two kinds of
combustion synthesis,namely Self-Ppropagating High
Temperature Synthesis (SHS) and Volume Combustion Synthesis (VCS). In both cases,
reactants may be pressed into a pellet, typically cylindrical in shape. The samples are then
heated by an external source (e.g., tungsten coil, laser) either locally (SHS) or uniformly (VCS)
to initiate an exothermic reaction.
4
Figure 1 a) SHS Ilustrations b) VCS Ilustrations
Ignition Techniques
The ECAS process is schematically shown in Figure 2.2. It simultaneously applies an
electric current along with a mechanical pressure in order to consolidate powders or synthesize
and simultaneously densify specific products with desired configuration and density. The applied
electric current and mechanical load may be constant throughout the sintering cycle or may vary
during the selected densification stages. In particular, the current may be adjusted by an
automatic controller so that a prescribed temperature cycle is followed.
5
Figure 2 ECAS Scheme
Green Mixture Density
Mixtured powder material are pressed in dies under high pressure to form them into the
required shape. The work part after compaction is called a green compact or simply a green, the
word green meaning not yet fully processed(Marinov).
As a result of compaction, the density of the part, called the green density is much
greater than the starting material density, but is not uniform in the green(Marinov)
Reactant gas undergoes mass transfer from the bulk gas stream to the pellet surface.
From the surface the gas must diffuse to arrive at a sharp interface between the grain particle
and the product layer for reaction to take place(Li, 2003).
Grain Size of Powder
Grain size influences many properties of particulate materials and is a valuable indicator
of quality and performance. This is true for powders, suspensions, emulsions, and aerosols. The
size and shape of powders influences flow and compaction properties. Smaller particles dissolve
more quickly and lead to higher suspension viscosities than larger ones. Smaller droplet sizes
6
and higher surface charge (zeta potential) will typically improve suspension and emulsion
stability.
Figure 3 Ti Powder grain size
7
METHODOLOGY OF PROJECT
Flow Chart of Project
Figure 4. Flow chart of project
8
Material
The powders were used in this work are aluminium (Al), titanium oxide (TiO2), carbon black (C)
and alumina (Al2O3).
Figure 5. TiO2 Powder
Figure 6. Al Powder
9
Figure 7. C Powder
Tools
1. Ohaus Advanturer Balance
Figure 8. Balance
10
2. Torque Wrench
Figure 9. Torque Wrench
3. Dies and Punch
Figure 10. Dies
11
4. Arch Welding Inverter
Figure 4. Arch Welding Inverter
12
RESULT and DISCUSSION
.
1. Synthesized Product
Pure material is a sample material composed of TiO2, Al, C with ratio of 3 : 4 : 3, without any
excess. After the sample is ignited using arch flame, we can observe the flame propagation on
its sample is very quick among all of sample. When material begins to react, its flashing can be
seen clearly.
Figure 12. Synthesized Product without Excess Addition
The sample with 20% exess material is a sample by adding 20% TiO2 and C so that it
has different number of mass material. On this process, the flame propagation of combusting
synthesis is not too much different with pure material. The flame propagation is still quick but not
as rapid as pure material.
13
Figure13. Synthesized Product with 20% Excess addtion
The mass of the sample is 1.288 gram or the sample with 40 % excess of TiO2 and C. In
this excess the flame propagation is starting slow when combusting process was conducted.
Flashing is appeared which means that material begins to react.
Figure 14. Synthesized Product with 40 % Excess
14
In 60 % Excess of TIO2 and C, it has slower flame propagation than before experiments
and there is flashing when the material start to react. The results of this experiment is solid
material can not be formed well because at half side of its material still in powder apperances.
Figure 55. Syntheesized Product with 60 % Excess
At 80% excess of TiO2 and C with the total mass material is 1.575 gram.The combustion
process cannot be done well since only small part of sample can be combusted.
15
Figure 66. Synthesized Product with 80 % Excess
Total mass material in this sample is 1.719 gram or 100% excess of TiO2 and C. At this
section the material cannot fine react during combustion process. The flame propagation does
not exist.
Figure 7. Synthesized Product with 100% Excess
16
2. XRD Pattern
XRD pure material result is a result of XRD in pure sample material without any excess
addition of stoichiometric compositions.
The XRD pattern of pure material describes that there is only two TiC detected by XRD
testing which is at approximately 45 in theta with 5 in intensity or counts and 80 in theta with 8 in
counts. Meanwhile, Al2O3 are detected as 6 points, namely at 31,37, 39, 45, 60, and 85 in 2
theta.
Figure 88. XRD Pattern without Excess
This is a result of XRD testing material with 20 % excess of TiO 2 and C. It can be
observed that TiC with 20% excess of TiO2 and C has increased from only one point become 3
points,they are at 35, 41 and 72 theta. There are seven of Al2O3 detected in this sample. Those
are at 19, 31, 37, 45, 60, 67 and 87 in 2 theta and the intensities are 9, 5, 23, 7, 7, 4 and 7.
17
Figure 9. XRD Pattern with 20 % Excess
18
This is last sample which is tested by XRD,40 % excess of TiO2 and C. Basically,for the 3rd
experimental,it has almost
same theta with the 2nd experiment but it has additional TiC
detected at 60 and 78 in 2 theta.
Figure 20. XRD Pattern With 40% Excess
3. Microsructures
It can be observed that the particle is heterogeneous in the shape and size. Some particles
show the shape like denrite, and others form a cubic shape. The Differences of Microstuctures
can be seen in Figure 21 to 23.
19
Figure 10. SEM Figure of Without Excess Synthesized Product
20
Figure 11. SEM Figure of With 20 % Excess
21
Figure 23. SEM Figure of With 20 % Excess
22
CONCLUSION AND SUGGESTIONS
Conclusions
Based on analysis and discussion above, there are some conclusions which can be
drawn as follows:
a. The production of ceramic material using combustion synthesis was succesful. The effect of
reactant composition has influenced the ignition and flame propagation.
b. The phase composition of the synthesized product can be detected using SEM and XRD.
Al2O3 can be clealry seen from the XRD pattern. However, XRD spectra of titanium caribide
(TiC) as one of product from combustion process does not appear. The effect of reactant
composition on the microstructure of the synthesized product can be observed from the
porosity of the reacted product, in which the increasing content of TiO 2 and C resulted in the
increase of porosity. The increasing content of TiO2 and C can also be identifued from the
XRD pattern. The more excess addition the higher peak result on XRD test.
Suggestions
From the experiment that has been done by researcher, there are several things that
need to be understood well in combustion process research,they are :
a. TiC cannot be observed in the reacted product. This is due to small size of TiC itself.
b. Combution process should be done in inside of a box to minimalize contact with oxygen
c. Balancing process should be done carefully by using mask because the powder grain is
very small and is not good to respiration.
23
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