Material and manufacturing technology V

Material and

Manufacturing

Technology V

Edited by

Meixing Guo

Syed Masood

Ghenadii Korotcenkov

Asif Mahmood

Material and Manufacturing

Technology V

Selected, peer reviewed papers from the

5th International Conference on

Material and Manufacturing Technology

(ICMMT 2014),

May 8-9, 2014, Kuala Lumpur, Malaysia

Edited by

Meixing Guo, Syed Masood,

Ghenadii Korotcenkov and Asif Mahmood

Copyright  2014 Trans Tech Publications Ltd, Switzerland

All rights reserved. No part of the contents of this publication may be reproduced or

transmitted in any form or by any means without the written permission of the

publisher.

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Volume 974 of

Advanced Materials Research

ISSN print 1022-6680

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ISSN web 1662-8985

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Preface

2014 5th International Conference on Material and Manufacturing Technology

(ICMMT 2014) was held in Kuala Lumpur, Malaysia during May 8-9, 2014. The

conference provides a platform to discuss Material and Manufacturing

Technology etc. with participants from all over the world, both from academia

and from industry. Its success is reflected in the papers received, with

participants coming from several countries, allowing a real multinational

multicultural exchange of experiences and ideas.

The present volumes collect accepted papers and represent an interesting

output of this conference. This book covers these topics: Advanced Materials

Engineering and Processing Technologies, Computing and Information

Technology, New Technologies, Methods and Technique in Civil Engineering,

and Achievements in Medical and Engineering Sciences.

After the peer‐ review process, the submitted papers were selected on the

basis of originality, significance, and clarity for the purpose of the conference.

The selected papers and additional late‐ breaking contributions to be

presented as lectures will make an exciting technical program. The conference

program is extremely rich, featuring high‐ impact presentation. We hope that

the conference results constituted significant contribution to the knowledge in

these up to date scientific field.

The proceeding records the fully refereed papers presented at the conference.

The main conference themes and tracks are Material and Manufacturing

Technology etc. Hopefully, all participants and other interested readers benefit

scientifically from the proceedings and also find it stimulating in the process.

This conference can only succeed as a team effort, so the editors want to

thank the international scientific committee and the reviewers for their

excellent work in reviewing the papers as well as their invaluable input and

advice.

Dr. Meixing Guo

Program Chair

Guizhou University, China

Committees

Honorary Chairs

Prof. Adrian OLARU, University Politehnica of Bucharest, Romania

Conference Chairs

Prof. Syed Masood, Swinburne University of Technology, Australia

Prof. Ahmed. A. D. Sarhan, University of Malaya, Malaysia

Program Chairs

Dr. Wasawat Nakkiew, Chiang Mai University, Thailand

Dr. M. M. Emara, Canadian International College(CIC), Egypt

Dr. İlhan ASİLTÜRK, Advanced Engineering and Manufacturing Laboratory (AEML),

USA

Dr. Kyoungjin Kim, Kumoh National Institute of Technology, Korea

Prof. Ghenadii Korotcenkov, Gwangju Institute of Science and Technology, Korea

Technical Committees

Dr. Pin-Chuan Chen, National Taiwan University of Science & Technology, Taiwan

Dr. P. SIVAPRAKASH, A. S. L. Pauls College of Engineering& Technology, India

Prof. Napiah Madzlan, Universiti Teknologi Petronas, Malaysia

Prof. Dr. Mohammed Jasim Kadhim, Iraq University of Technology, Iraq

Prof. Guy Littlefair, Deakin University, Australia

Dr. S. Narayanan, Senior Professor & Pro-Vice Chancellor, Vellore Institute of

Technology, Vellore, India

Prof. L. C. Tsao, National Pingtung University of Science and Technology, Taiwan

Prof. Seyed Mehdi Rezaei, University of Malaya, Malaysia

Dr. Jae Hoon Lee, POSCO Technical Research Laboratories, Korea

Prof. Muhammad ANIS, University of Indonesia, INDONESIA

Prof. Dr. Anika Zafiah Mohd Rus, Universiti Tun Hussein Onn Malaysia, Malaysia

Prof. Yu SUN, Nanjing Unviersity of Science & Technology, China

Prof. Taufik K. Aboud, University of Tripoli, Libya

Prof. Lou Yan, Shenzhen University, China

Dr. Y. S. Reddy, Chaitanya Bharathi Institute of Technology, India

Dr. Koichiro Fukui, Yokohama National University, Japan

Prof. Mohsen Abdelnaeim Hassan Mohamed, University of Malaya, Malaysia

Prof. Anjaiah Devineni, Manipal University, India

Dr. Mum Wai Yip, Tunku Abdul Rahman College, Malaysia

Dr. Pongsaton Amornpitoksuk, Prince of Songkla University, Thailand

Dr. Sachin Shendokar, College of Engineering, India

Dr. Jiraphon Srisertpol, Suranaree University of Technology, Thailand

Dr. Yusairie Mohd, Universiti Teknologi Mara, Malaysia

Prof. Lung-Chuan Tsao, National Pingtung University of Science and Technology,

Taiwan

Prof. Anjaiah Devineni, Manipal University, India

Dr. Ahmed Sarhan, University of Malaya, Malaysia

Prof. Ming-piao Tsai, National Formosa University, Taiwan

Prof. Marcus Shaffer, Department of Architecture, Pennsylvania State University,

USA

Prof. Ho-Sung Lee, Korea Aerospace Research Institute, Korea

Prof. TURNAD Lenggo Ginta, UNIVERSITI TEKNOLOGI PETRONAS, MALAYSIA

Prof. Smit Insiripong, Muban Chombueng Rajabhat University, Thailand

Dr. Dhananjay M. Kulkarni, Birla Institute of Technology & Science, India

Prof. Asif Mahmood, King Saud University (KSU), Saudi Arabia

Dr. TAN CHEE-FAI, Universiti Teknikal Malaysia Melaka, Malaysia

Sponsors

Swinburne University of Technology, Australia

Table of Contents

Preface, Committees and Sponsors

Chapter 1: Advanced Materials Engineering and Processing

Technologies

Improvement of Mechanical Properties of Al2O3-SiC Composite with ZrO2 (3Y) Particles

S. Watcharamaisakul 3

Prediction of Long – Term Creep Properties of Kenaf Fiber Unsaturated Polyester

Composites

S.A. Mutasher and E.A. Osman 9

Effect of Catalyst Concentration on Performance of Hybrid CNT-Carbon Fibre

Nanocomposite

I.S. Norazian, A.R. Suraya, A. Norhafizah, T.M.T. Amran and N. Alias 15

Electrophoretic Deposition of Titanium Dioxide (TiO2) Nanoparticles on Ceramic

Membrane

M.Y. Noorsuhana and N.H. Abdul Aziz 20

Green Nanoparticle Oil Well Cement from Agro Waste Rice Husk Ash

N. Alias, M.M.M. Nawang, N.A. Ghazali, T.A.T. Mohd, S.F.A. Manaf, A. Sauki, M.Z.

Shahruddin and N.A. Ramlee 26

A New Double Negative Metamaterial for C-Band Microwave Applications

S.I. Sikder, R.I.F. Mohammad and T.I. Mohammad 33

Sound Absorption Properties of Dwi Matrix Renewable and Synthetic Polymer

N.Q.A. Adnan and A.Z.M. Rus 38

Effect of Alkaline Phosphate-Permanganate Conversion Coating on the Corrosion

Resistance of AZ91D Magnesium Alloy

Y.M. Byoun, J.H. Jeong, J.K. Park, S.K. Seo and C.H. Lee 43

Formation of Cobalt Nanoparticles from Co(OH)2 Suspension

M.D.L. Balela, S. Yagi and E. Matsubara 50

Effect of Calcination Temperature on the Morphology of Carbon Nanosphere Synthesized

from Polymethylmethacrylate

A.F. Al-Ahmadi, M.A. Al-Daous and T.A. Saleh 55

Effect of Fe Substituted Co-Free AB3-Type Hydrogen Storage Alloys Used for Ni-MH

Batteries: A First-Principles Investigation

M.Y. Zhang, F. Wu, D.B. Mu and G.Q. Cao 60

Characteristics of AB3-Type Co-Free Hydrogen Storage Alloy in Low-Temperature

Condition

W. Li, M.Y. Zhang, D.B. Mu, T. Yang and F. Wu 66

Thermal Properties of NiCrSiB Coating on Piston Engine

N.B. Baba, M.M.A. Omar and N.A.M. Zin 71

Material and Structural Engineering of Metal Oxides Aimed for Gas Sensor Applications

G. Korotcenkov and B.K. Cho 76

Investigation of Er3+ Doped in Na2O-Al2O3-BaO-CaO-Sb2O3-B2O3 -SiO2 Glasses: Physical,

Optical and Visible Luminescence Properties

S. Tuscharoen, N. Chanthima and J. Kaewkhao 86

Composite Copolymer Acrylamide/Bacterial Cellulose Hydrogel Synthesis and

Characterization by the Application of Gamma Irradiation

S. Mulijani, Erizal, T.T. Irawadi and T.C. Katresna 91

The Characterization of Chitosan-Hyaluronan-Metal Nanocomposites

Y.C. Shih, H.H. Hsieh, T.M. Wu and C.W. Chou 97

Uncured Properties of Silica Filled ENR Compounds at High Temperature Curing

M.M. Kamal and M.Z. Zakaria 102

Electroless Deposition of Nickel Nanoparticles at Room Temperature

M.D.L. Balela, S. Yagi and E. Matsubara 107

b Material and Manufacturing Technology V

Cysteine Conjugated Gold Nanoparticles and their Scavenging Free Radicals Properties

C.W. Chou, J.M. Yang, T.S. Yang, Y.C. Shih, H.H. Hsieh, K.H. Chang, K.S. Chen, W.L. Tzu,

Y.C. Hseu and Y.S. Wei 112

Improving the Structural, Optical and Electrical Properties of ITO Nano-Layered Thin

Films by Gas Flow Argon

Q.Z. Mehdi, G. Hegde, M.A. Bin Juusoh, J.B. Al-Dabbagh and N.M. Ahmed 116

Laser Assisted Machining of Ti10V2Fe3Al and Ti6Cr5Mo5V4Al β Titanium Alloys

R.A. Rahman Rashid, S. Sun, S. Palanisamy and M.S. Dargusch 121

Comparison of Endmill Tool Coating Performance during Machining of Ti6Al4V Alloy

S. Palanisamy, R.A. Rahman Rashid, M. Brandt, S. Sun and M.S. Dargusch 126

Experimental Study of Micro-Milling Microchannels on Polycarbonate Substrates

P.C. Chen and C.W. Pan 132

Tool Life Study of Coated/Uncoated Carbide Inserts during Turning of Ti6Al4V

S. Palanisamy, R.A. Rahman Rashid, M. Brandt and M.S. Dargusch 136

Compressive Properties of Solid and Porous Parts Made from High Strength Steel Alloys by

Direct Metal Deposition

S.H. Riza, S.H. Masood and C.E. Wen 141

Computational Analysis of Single and Multiple Impacts of Low Pressure and High Pressure

Cold Sprayed Aluminum Particles Using SPH

S.N.A. Yusof, A. Manap, H. Misran and S.Z. Othman 147

Characterization of Thermal Sprayed Titanium/Hydroxyapatite Composite Coating on

Stainless Steel

N.H. Azhar, M.K. Talari, R. Ramli and C.K. Koong 152

Effect of Sintering Temperature on Dielectric Properties of CaCu3Ti4O12 Ceramics

Prepared by Mechanochemical Process

M. Mohamed, M.K. Talari, M.S.M. Deni and A. Zakaria 157

Surface Alloying of Copper Substrate Coated by Fe-Si by Using CO2 Laser

A.M.Y. Taher 162

Analysis of Roughness and Heat Affected Zone of Steel Plates Obtained by Laser Cutting

I. Miraoui, M. Boujelbene and E. Bayraktar 169

The Influence of SS316L Foam Fabrication Parameter Using Powder Metallurgy Route

N.I. Mad Rosip, S. Ahmad, K.R. Jamaluddin and F. Mat Nor 174

Effect of Process Parameters in Hot Press Forming Operation to Tensile Strength of Ultra

High Strength Steel

M.Z. Zawawi and N.M.H.A. Nik Haron 179

Characterization and Comparison of Thermally Sprayed Hard Coatings as Alternative to

Hard Chrome Plating

K. Meekhanthong and S. Wirojanupatump 183

Ultimate Elastic Wall Stress (UEWS) Test under Biaxial Loading for Glass-Fibre

Reinforced Epoxy (GRE) Pipes

T.A. Assaleh and L.A. Almagguz 188

Processability Behaviour of Dual Filler Systems Reinforced Epoxised Natural Rubber

T.Z. Zaeimoedin and M.M. Kamal 195

Microstructure and Hardness of Diffusion Bonded Sialon-AISI 420 Martensitic Stainless

Steel

N.N.M. Ibrahim, P. Hussain and M. Awang 199

Simulation of Dirac Tunneling Current of an Armchair Graphene Nanoribbon-Based P-N

Junction Using a Transfer Matrix Method

E. Suhendi, R. Syariati, F.A. Noor, N. Kurniasih and Khairurrijal 205

Electrical Coupling of Organic/Inorganic Semiconductor Interfaces: A Comparative Study

M. Dhingra, S. Shrivastava, P. Senthil Kumar and S. Annapoorni 210

Performance Analysis of a LTE Band Microstrip Antenna on FR-4 Material

A.U. Ahmed, R. Azim, T.I. Mohammad, M. Ismail and M.S. Islam 215

Measurement of Liquid Film Thickness around Horizontal Tube Bundle by Optical

Technique for Optimizing Evaporator Design and Manufacturing

K. Bourouni and A.L. Taee 220

Study on Using EDXRF for the Determination of Gold Coating Thickness

M.Y.M. Sulaiman and M. Muslimin 225

Advanced Materials Research Vol. 974 c

The Effect of Oxidized White Liquor on Pulp Brightness in Peroxide Bleaching in Pulp

Mills

N. Khajornpaisan and N. Rojanarowan 230

Tumoricidal Effect of Hematite (α-Fe2O3) and SiO2 Nanoparticles in Human

Rhabdomyosarcoma Cell Line

M. Hammad Aziz, M. Fatima, M. Waseem, M. Fakhar-E-Alam, M. Afzal and M. Nadeem

Shakoor 235

Evaluation of Mixed Cellulase-Amylase System on Enzymatic Hydrolysis Reaction Using

Response Surface Methodology

F. Hamzah, N.H. Saleh, N. Alimin and M.S. So’aib 241

Influence of Shear Rate on Proteins Separation, Molecular Weight Cut-Off and Average

Pore Size of Polysulfone Blend Membranes

A. Ali, R.M. Yunus, M. Awang and S. Hamzah 247

Characteristics of UV Irradiated Waste Biopolymer from Renewable Resources (Part 1)

S.M. Rus, N.A. Latif, M.I. Ghazali and A.Z.M. Rus 252

Characteristics of UV Irradiated Waste Biopolymer from Renewable Resources (Part 2)

S.M. Rus, M.I. Ghazali and A.Z.M. Rus 257

Surface Modified Nano Calcium Oxide for Base Heterogeneous Transesterification of

Kappaphycus Alvarezii Seaweed to Biofuel

A.R. Yacob, N.F. Sulaiman and M. Khalid Qasim 262

Chapter 2: Computing and Information Technology

A New Reinforcement Learning for Train Marshaling with Generalization Capability

Y. Hirashima 269

Performance Enhancement of 10 Gbps OCDMA Networks Using DPSK and DQPSK with

Unique Code-Sequence

G.Y. Li, T.T.H. Gilbert and K. Dimyati 274

Vehicle Scheduling Model for Fresh Agriculture Products Pickup with Uncertain Demands

L.X. Rong and H.B. Sha 282

Application of Auxiliary Antenna Elements for SAR Reduction in the Human Head

M.I. Hossain, R.I.F. Mohammad, M.T. Islam and N.H.M. Hanafi 288

Thinking on the Progressive Failure Analysis of the Slope

X.P. Wang, X. Xia, K. Hu and J.C. Feng 293

The Use of the Six Sigma Approach to Minimize the Defective Rate from Bending Defects in

Hard Disk Drive Media Disks

S. Suriyasuphapong and N. Rojanarowan 298

Extended Supply Chain DEA for Considering Replaceable DMUs

W. Chaowarat, H. Suto and P. Piboonrungroj 305

A New Hybrid Model for Forecasting Crude Oil Price and the Techniques in the Model

J.W. Zheng, S.X. Li and Y. Kun 310

Analysis of Elastic-Plastic Responses of a Water Tower Structure during an Earthquake

Based on the Transfer Matrix Method of Multibody System

H.J. Huang, J.G. Ding and Z. Qiao 318

Chapter 3: New Technologies, Methods and Technique in Civil

Engineering

Nanotechnology: The Emerging Field of Civil Engineering Particularly in Developing

Countries

T. Manzur, M. Bashar Emon and K. Islam 329

An Experiment on Durability Test (RCPT) of Concrete According to ASTM Standard

Method Using Low-Cost Equipments

S. Iffat, A.B. Emon, T. Manzur and S.I. Ahmad 335

Deep Pit Foundation Steel Sheet Pile Supporting Scheme of the 274# Pile Cap for Super

Large Bridge over the Coastal Expressway and the North Jiangsu Irrigation Canal

K. Huang and R.W. Feng 341

d Material and Manufacturing Technology V

Effect of LRB Position for Vibration Reduction System of Self-Anchored Cable-Stayed

Suspension Bridge

F. Miao 346

Investigation of Engineering Properties of Quarry Waste in the East of Thailand for Used as

Fine Aggregate in Concrete

S. Sinthaworn, T. Koseekageepat and O. Saengmanee 350

Chapter 4: Achievements in Medical and Engineering Sciences

Step Response Identification for a Batch Reaction Vegetable Oil Transesterification

T. Rachmanto, D. Allanson and C. Matthews 357

Analysis of Fuel Injection Parameter on Biodiesel and Diesel Spray Characteristics Using

Common Rail System

A. Khalid, A. Sapit, M.N. Anuar, R. Him, B. Manshoor, I. Zaman and Z. Ngali 362

Gas Lift Optimization of an Oil Field in Malaysia

N.A. Ghazali, T.A.T. Mohd, N. Alias, E. Yahya, M.Z. Shahruddin, A. Azizi and A.Y. Fazil 367

A New Method for Reconstruction of Corneal Topography with Placido Disk System

D.W. Gong, J.H. Chen, C. Yuan, R.K. Ge and M.H. Zhou 373

Bacterial and Fungal Decolorization of the Remazol Dye in Textile Effluent of Malaysian

Cottage Industries by Lactobacillus delbrueckii and Pleurotus ostreatus

C.R. Nurhaslina, R. Nur Hazirah and K.H. Ku Halim 379

Comparison of Pineapple Leaf and Cassava Peel by Chemical Properties and Morphology

Characterization

Z. Daud, H. Awang, A.S.M. Kassim, M.Z.M. Hatta and A.M. Aripin 384

The Study of Bone Cutting Force with FEM

S. Liu, D.M. Wu and J. Zhao 389

Anticandidal Activity of Cratoxylum formosum Gum and its Cytotoxicity

S. Thaweboon, B. Thaweboon, S. Dechkunakorn, P. Nisalak and R. Kaypetch 394

Auxetic Plates on Auxetic Foundation

T.C. Lim 398

A Simple GA Based Approach for Multi-Objective Optimization of Machining Parameters

A. Waseem, J.F. Su, W.Y. Chen and P.F. Sun 402

Optimization of Friction Stir Welding Parameters with Simultaneous Multiple Response

Consideration Using Multi-Objective Taguchi Method

M.A. Mohamed, Y.H. Manurung, M.R.A. Rahim, N. Muhammad and F.A. Ghazali 408

Determination of Bore Grinding Machine Parameters to Reduce Cycle Time

S. Buddhachakara and W. Tharmmaphornphilas 413

CHAPTER 1:

Advanced Materials Engineering and Processing

Technologies

Improvement of Mechanical Properties of Al2O3-SiC Composite with

ZrO2 (3Y) Particles

S. Watcharamaisakul

School of Ceramic Engineering, Institute of Engineering, Suranaree University of Technology 111

University Avenue, Muang District, Nakhon Ratchasima 30000, Thailand.

[email protected]

Keywords: ZrO2(3Y) particles, Al2O3-SiC composites, mechanical properties

Abstract. The mechanical properties of Al2O3-SiC based composites were improved by the

addition of ZrO2(3Y) particles in the range of 10 to 25 vol.%. Al2O3-SiC/ZrO2(3Y) composites were

manufactured by pressureless sintering at 1550, 1600, and 1650oC. Sintered composites were

characterized for density, XRD, microstructure and mechanical properties such as flexural strength,

fracture toughness and hardness. The results showed that the highest flexural strength of 250 MPa

was obtained with 25 vol.% ZrO2(3Y) composite sintered at 1600oC due to higher density and

smaller Al2O3 grains in comparison with samples sintered at 1550oC and 1650oC, respectively. The

maximum fracture toughness of 5.66 MPa.m1/2 was obtained with 20 vol.% ZrO2(3Y) sintered at

1600oC. The highest hardness of 9.16 GPa was obtained with composite of 10 vol.% ZrO2(3Y)

sintered at 1600oC as it contains the largest amount of hard SiC.

Introduction

Alumina ceramics (Al2O3) has been widely used as a matrix material because of its good

mechanical properties such as high hardness, low electrical conductivity, good chemical stability

and oxidation resistance. However, the low fracture toughness of Al2O3 limits its use in structural

applications. Thus, many research studies have focused on improving the mechanical properties of

Al2O3 through the addition of various reinforcing particles such as SiC, ZrO2, TiN/TiC/TiO2, BN

and metal particles [1-3]. Most of these efforts have made use of SiC particles for reinforcement of

Al2O3. Shi et al. [4] studied the effect of SiC amount on mechanical properties of Al2O3-SiC

composites. The flexural strength of composite was increased with addition of 20 wt% SiC and the

highest fracture toughness was obtained with the sample containing 5 wt% SiC. Ko et al. [5]

particularly focused their study on the effect of submicrometer SiC reinforced in Al2O3 matrix.

They showed that SiC can improve flexural strength properties of Al2O3 matrix, while the

toughness properties were less improved. Ma et al. [6] studied ZrO2 toughening mechanism in

Al2O3 matrix. Their results confirmed that ZrO2(2Y) and ZrO2(3Y) could increase the fracture

toughness of Al2O3 matrix.

The aim of the present work is to investigate the influence of the addition of various amounts of

ZrO2(3Y) on mechanical properties of Al2O3-SiC composites such as flexural strength, fracture

toughness and hardness.

Experimental Procedures

Al2O3 particles (98.50% purity, ACG-2A, Sigma-Aldrich) with a mean size of 3 µm, β-SiC

(Ultrafine, Ibiden Co., Nagoya, Japan) with a mean size of 100 nm and ZrO2 (3Y) with 3 mol%

Y2O3 stabilizer (Hanwha Ceramics Co., Australia) with a mean size of 1 µm were used as starting

powders. Batch compositions and sintering conditions are summarized in Table 1.

Advanced Materials Research Vol. 974 (2014) pp 3-8

© (2014) Trans Tech Publications, Switzerland

doi:10.4028/www.scientific.net/AMR.974.3

Table 1: Batch compositions and sintering conditions

To investigate the effect of zirconia addition on mechanical properties of the composite, the

amount of ZrO2 was varied from 10 to 25 vol.%. The raw powders of Al2O3, SiC and ZrO2(3Y)

were mixed by ball-milling in ethanol for 24 h using Al2O3 balls and a polyethylene jar. The mixed

slurry was dried and subsequently sieved through a 60 mesh screen to prepare the granulated

powder. Then, the granulated powder was pressed into a pellet of compacted sample under a

pressure of 25 MPa. The green bodies were placed in the Al2O3 and graphite protective powder bed

in an alumina crucible and pressureless sintered at 1550, 1600 and 1650oC for 4 h. Densities of the

sintered specimens were determined by Archimedes method with distilled water as the immersion

medium. The sintered specimens were ground and polished up to 1 µm, then etched thermally. The

specimen microstructure was observed using scanning electron microscopy (SEM). The phase

identification was carried out by means of X-ray diffraction (XRD). The flexural strength was

measured with a three-point bending test [7]. The hardness was measured using a Vickers indenter.

The fracture toughness was determined by the indentation method from Vickers impression marks.

Results and Discussion

Microstructure. Figure 1 shows SEM micrographs of AS90Z10 sample (90 vol.% (95:5 Al2O3-

SiC) and 10 vol.% ZrO2) sintered at 1550, 1600, and 1650oC. The etched surface observations

confirmed that the amount of porosity decreases with increasing sintering temperature and a sample

of high density is obtained at 1650oC. These observations also proved that the zirconia phase is

mainly localized at the grain boundaries of Al2O3. The amount of zirconia phase located at the grain

boundaries seems to be enhanced by increasing sintering temperature for the composite of the same

addition of ZrO2(3Y) powder. The presence of ZrO2 phase can prohibit the crack propagation to

enhance the fracture toughness of composites [8].

4 Material and Manufacturing Technology V

Fig.1: SEM micrographs of AS90Z10 sintered at (a) 1550o

(b) 1600oC and (c) 1650oC

Fig. 2: SEM micrographs of composites sintered at 1650oC:

(a) AS90Z10, (b) AS85Z15, (c) AS80Z20 and (d) AS75Z25

Figure 2 illustrates SEM micrographs of samples of various amounts of ZrO2(3Y) sintered at

1650oC. Microcracks were observed in all samples. These microcracks are induced by the

compressive stresses around Al2O3 grain boundaries due to the tetragonal (t) to monoclinic (m)

phase transformation in ZrO2 at high sintering temperature [7]. The higher number of microcracks

was detected in the sample containing 25 vol.% ZrO2(3Y) in comparison with samples with less

zirconia due to the large amount of phase transformation of t-ZrO2 to m-ZrO2 during cooling down

after sintering.

Advanced Materials Research Vol. 974 5