Pulse electric current synthesis and processing of materials

Pulse Electric

Current Synthesis and

Processing of Materials

Pulse Electric

Current Synthesis and

Processing of Materials

Proceedings of the 6th Pacific Rim

Conference on Ceramics and Glass Technology

(PacRim6), September 11-16, Maui, Hawaii

Editors

Zuhair A. Munir

Manshi Ohyanagi

Masao Tokita

Michael Khor

Toshio Hirai

Umberto Anselmi-Tamburini

VX/INTERSCIENCE

A JOHN WILEY & SONS, INC., PUBLICATION

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Contents

Preface ix

The SPS Process: Characterization and Fundamental Investigations

Study on the Process Mechanism in Spark Plasma Sintering 3

Zhengyi Fu, Kun Wang, Tianya Tan, Yan Xiong, Daihua He, Yucheng Wang,

and Zuhair A. Munir

The Spark-Plasma-Sintering (SPS) Process in Comparison With 23

Various Conventional Compaction Methods

Paul Angerer, Erich Neubauer, Li Gen Yu, and Khiam Aik Khor

Fundamental Investigations of Reactivity and Densification in 37

the SPS

U. Anselmi-Tamburini and Z. A. Munir

Development of Advanced Spark Plasma Sintering (SPS) Systems 51

and Its Industrial Applications

Masao Tokita

Calculation of Electric Field and Spark of Punch Surface For Pulsed 61

Electric Current Sintering

D. M. Zhang, L. M. Zhang, and Z. Z. Wang

Sintering Studies by Pulsed Electric Current

Preparation of Porous Alumina Ceramics by Spark Plasma Sintering 73

Won-Seung Cho, Yeon-Chul Yoo, Chin Myung Whang, Nam-Hee Cho,

Jun-Gyu Kim, Young-Jae Kwon, and Z. A. Munir

Ti/Hydroxyapatite Hybrid Material Prepared by Spark 83

Plasma Sintering

T. Tsujimoto, T. Tanaka, K. Oshiro, H. Fujimori, M. Matsuura, S. Goto, and

S. Yamamoto

v

Sintering Behavior of Aluminum Alloy-Carbon Composite by SPS 89

Takashi Yoshioka, Kiminori Sato, Shinsuke Tanaka, Sumasu Yamada, and

Yukio Makino

Spark Plasma Sintering of Less-Crystallized Boron Carbide 101

with Defects

Yasuhiro Kodera, Naoaki Isibashi, Takahito Imai, Takeshi Yamamoto,

Manshi Ohyanagi, Umberto Anselmi-Tamburini, and Zuhair A. Munir

High-Density (Na, K)Nb03 Piezoelectric Ceramics Fabricated by 113

Spark Plasma Sintering

T. Saito, T. Ochiai, Y. Matsuo, and T. Wada

Preparation of Amorphous Sintered Body 125

Kazuyuki Kakegawa, Naoki Akiyama, Sofia Saori Suzuki, Naofumi Uekawa, and

Takashi Kojima

SiCp/AI Composites Fabricated by Spark Plasma Sintering 133

L M. Zhang, X. F. Gu, D. M. Zhang, M. J. Yang, and Z. Z. Wang

Structural Transformation of Stacking Disorder SiC with Densification 143

by Spark Plasma Sintering

Yasuhiro Kodera, Naoki Toyofuku, Takeshi Yamamoto, Manshi Ohyanagi, and

Zuhair A. Munir

Consolidation of Carbon Material with Disordered Structure by 153

Spark Plasma Sintering

Takeshi A. Yamamoto, Takayuki Nakayama, Manshi Ohyanagi, Atsuki Kaneuchi,

and Zuhair A. Munir

Spark Sintering Rate of Pure Copper Powder Compact 161

K. Matsugi, H. Kuramoto, G. Sasaki, and O. Yanagisawa

Synthesis/Sintering of Dense Carbides-, Borides- and Perovskites- 173

Based Materials by SPS

Antonio Mario Locci, Roberta Licheri, Roberto Orru, Alberto Cincotti, and

Giacomo Cao

Simultaneous Synthesis and Densification of TiSi2/SiC Submicron- 189

Composites via Spark Plasma Sintering

Lianjun Wang, Wan Jiang, Chao Qin, and Lidong Chen

Consolidation of Nanostructured Materials

Spark Sintering of Electroless Nickel or Tin Plated Metal, Carbide 197

Oxide and Sulfide Powders

K. Matsugi, G. Sasaki, and O. Yanagisawa

vi • Pulse Electric Current Synthesis and Processing of Materials

Synthesis and Consolidation of Zirconia Nanopowders via a Unique 209

Reverse Micelle Synthesis Process and Spark Plasma Sintering

Olivia A. Graeve, Harpreet Singh, and Andrew Clifton

Consolidation of Nano-Ceramics by SPS; Kinetic Considerations 225

Mats Nygren and Zhijian Shen

Production of Dense Nanostructured Materials Using FAPAS and 235

SPS Techniques

Frederic Bernard, Eric Gaffet, and Zuhair Munir

Pore Free Consolidation with Nanocrystalline Control in Ceramics 251

Hiroshi Kimura

Property Evaluation of Pulse Electric Current Sintered Materials

Mechanical Properties of Hydroxyapatites Sintered by Spark 265

Plasma Sintering

Takumi Nakamura, Tatsuya Fukuhara, and Hiroshi Izui

Evaluation of Al-Si-C-N Ceramics Fabricated by Spark Plasma 273

Sintering

Ryota Kobayashi, Junichi Tatami, Toru Wakihara, Katsutoshi Komeya,

Takeshi Meguro, and Takashi Goto

Thermoelectric Properties of P-Type Bio^Sb-, 5Te3 Compounds 279

Prepared by Spark Plasma Sintering Method

D. C. Cho, S. Y. Kim, C. H. Lim, W. S. Cho, C. H. Lee, S. Y. Shin, and Z. A. Munir

Mechanical Properties of Ti-15-3 Alloy Reinforced With SiC Fibers 289

by Spark Plasma Sintering

Hiroshi Izui, So Kinbara, and Michiharu Okano

Crystallographic Behaviors of Nano-Powder Anatase Consolidated 301

by SPS Method

Yukio Makino

Index 313

Pulse Electric Current Synthesis and Processing of Materials • vii

Preface

Sintering as an art had origins that are thousands of years old. The formation of

bricks by heating clay bodies in an open pit fire is one of the earliest examples of

sintering practiced by ancient civilizations of Mesopotamia. The practice is known

to have existed as far back as 6000 BC. Understanding the basic phenomena and

the important parameters governing sintering has led to investigation on means to

activate the process. The objective of these investigations was to enhance mass

transport to either make possible the sintering of extremely refractory materials or

to lower the temperature of consolidation. One of the methods of activating the

sintering process involves the use of electrical current. Although the recent wide￾spread use of this approach has been generated by the availability of commercial￾ly built devices, its origin is much older. Patents issued as early as 1933 describe

methods in which an electric discharge or current is utilized to aid in the sintering

of powders or the sinter-joining of metals. The use of a current to aid in the sin￾tering of materials has been applied in a large number of investigations.

Commercial units, which have been developed over the past few decades, include

"plasma-activated sintering" (PAS), "pulsed electric current sintering" (PECS),

"electroconsolidation" also known as electric pulse assisted consolidation (EPAC),

and "spark plasma sintering" (SPS). Although the generic name pulse electric cur￾rent sintering (PECS) is gaining popularity, most published papers use the term

SPS to refer to the method.

The emerging theme from the large majority of investigations of current acti￾vated sintering is that it has decided advantages over conventional methods in￾cluding pressureless sintering, hot-pressing, and others. These advantages include:

lower sintering temperature, shorter holding time, and marked comparative im￾provements in properties of materials consolidated by this method. Lower temper￾atures and shorter holding times have made it possible to sinter nanometric pow￾ders to near theoretical values with little grain growth. While in most cases the

evidence demonstrating the superiority of the current activated sintering is clearly

presented, the explanations given to rationalize these advantages fall short of sci￾entific adequacy.

IX

The importance of the SPS method as a tool for consolidation of powders

process is demonstrated by the large number of papers published during the past

decade. There has been a seemingly exponential increase in the number of papers

published since 1994. In that year only a handful of papers were published while in

the last year with complete data (2003), more than 150 papers were published.

Since the effort to commercialize the method was initiated in large scale in Japan, it

is not surprising that the vas majority of papers published are from Japan. China and

Korea are second and third, respectively, while the other countries contributed few￾er than about 30 papers each. In part this distribution reflects the availability of the

equipment in these countries, with Japan having by far the largest number of SPS

units.

In view of the above, it is not surprising that four symposia on the topic of SPS

have been organized in the past. The fifth and most recent symposium was orga￾nized to be part of the 6th Pacific Rim Conference on Ceramic and Glass Technolo￾gy (PAC RIM 6), which was held September 11-16, 2005 in Maui, Hawaii. The

proceedings of the Fifth International Symposium on Spark Plasma Synthesis and

Processing (ISSPSP-5) are printed in this volume of Ceramic Transactions. This

represents the first effort to publish the Proceedings in a widely distributed publica￾tion forum.

In organizing the symposium we have planned sessions on the following topics:

The SPS Process: Characterization and Fundamental Investigations

Sintering Studies by Pulsed Electric Current

Consolidation of Nanostructured Materials

Property Evaluation of Pulse Electric Current Sintered Materials

This proceedings is organized to reflect these topics. We are hopeful that the col￾lection of these papers, representing the most recent work on the SPS process, will

provide an important source of information to scientists in the worldwide communi￾ty of synthesis and processing of materials. The papers in this volume present both

fundamental and applied work. In the former, many attempts have been made to

provide a fundamental understanding to the SPS process, and in the latter investiga￾tions have been made demonstrating success in synthesizing or consolidating mate￾rials possessing unusual or highly improved properties.

We are grateful to the assistance provided to us by several individuals. We

thank Dr. Sylvia M. Johnson, the General Chair of PacRim 6 for her support. We

are indebted to the meetings and technical publications staff at The American

Ceramic Society for their help with the review process of the submitted papers.

Without their help this Ceramic Transactions volume would not have been possi￾ble.

Finally, we express our gratitude to the organizations that provided financial

support to provide travel assistance to invited speakers. We are grateful to: The

National Science Foundation (Dr. Linda Blevins, Program Director); The U.S.

Army Research Office, ARO (Dr. William Mullins, Program Director); Sumitomo

x • Pulse Electric Current Synthesis and Processing of Materials

Coal Mining Company, Ltd. (Currently: SPS Syntex, Inc.); SCM Systems, Inc.;

Suga Company Ltd.; and Bits Corporation (Mr. Yoshio Kanno, President).

Zuhair A. Munir, University of California, Davis, USA

Manshi Ohyanagi, Ryukoku University, Japan

Masao Tokita, SPS Syntex, Inc., Japan

Michael Khor, Nanyang Technological University, Singapore

Toshio Hirai, Japan Fine Ceramics Center, Japan

Umberto Anselmi-Tamburini, University of Pavia, Italy

Pulse Electric Current Synthesis and Processing of Materials • xi

The SPS Process:

Characterization and

Fundamental Investigations

Pulse Electric Current Synthesis and Processing of Materials

Edited by Zuhair A. Munir, Manshi Ohyanagi, Masao Tokita,

Michael Khor, Toshio Hirai and Umberto Anselmi-Tamburini

Copyright © 2006 The American Ceramics Society

STUDY ON THE PROCESS MECHANISM IN SPARK PLASMA SINTERING

Zhengyi FU *, Kun WANQ Tianya TAN, Yan XIONG, Daihua HE, Yucheng WANG

State Key Lab of Advanced Technology for Materials Synthesis and Processing

122 Luoshi Road, Wuhan University of Technology

Wuhan, Hubei Province, P. R. China, 430070

ZuhairA.MUNIR

Department of Chemical Engineering and Materials Science

University of California, Davis

CA 95616, USA

ABSTRACT

The paper presents results on the mechanism of spark plasma sintering (SPS). First, the

temperature distribution in the sample and the die in SPS were studied. Under certain conditions,

the difference may reach a few hundreds of degrees of centigrade. Controlling of processing

parameters can decrease the temperature difference. Second, the process of atomic diffusion due to

the effect of the current was also studied. It was found that the atomic diffusion is enhanced at the

interface between specimens in the SPS relative to hot pressing (HP). Third, we have utilized the

SPS process to form transparent ceramics, porous metals and ceramics, and to effect welding of

alloys.

1. INTRODUCTION

Spark Plasma Sintering (SPS) is a newly developed synthesis and processing technology. It

enjoys inherent advantages, such as high thermo-efficiency, rapid heat-up, making it possible to

sinter at low temperatures and for short times

[1l The temperature field during the SPS process is

an important consideration because of the high rates of heat-up. Since temperature plays a key role

in the formation of the structure and performance of a material, understanding the temperature

distribution in the sample is of great importance to the production of high quality materials. On the

other hand, atomic diffusion is another key factor in the SPS. Finding out if the special electric and

magnetic fields produced by pulse current have an effect on the atomic diffusion is a key to

understanding the mechanism of SPS. Experimental observations showed the suitability of the

SPS process for the preparation of transparent ceramics, porous metals and ceramics, and for

joining of alloys.

2. STUDY OF TEMPERATURE FILEDS IN SPARK PLASMA SINTERING

2.1. Calculations of temperature distribution

The ANSIS software was used for calculating the heating process. We assumed the heat

3

Pulse Electric Current Synthesis and Processing of Materials

Edited by Zuhair A. Munir, Manshi Ohyanagi, Masao Tokita,

Michael Khor, Toshio Hirai and Umberto Anselmi-Tamburini

Copyright © 2006 The American Ceramics Society

Study on the Process Mechanism in Spark Plasma Sintering

conductivity of the die is the same as the sample, and the heating rate of the sample and die is

distributed evenly. Solving the energy conservation differential equation with internal heat source,

we can get the deduced results of the temperature difference between the center of the sample and

a point of the centrosymmetric plane at final sintering stage[2]:

In sample (O^n ) AT = -WAr

i (1)

In die (ri « r 2 ) AT = -^r 2

+ * ^ (2)

V

4k2 4k2

l v

'

Where r is radius of the sample or the die, ri the largest semi-diameter of the sample, r2 the

largest semi-diameter of the die, T the inner temperature of the sample or die, ki and k2 refer to the

thermal conductivity of the sample and graphite, respectively; while dq/dt refers to their heating

rates.

2.2. Experimental procedure of temperature measurement

Temperatures were measured at different points with thermocouples. Two layouts of

placements of thermocouples are shown in Fig.l[3]

. In Fig.l (a), point 1 is at the center of the

sample and point 2 is at the border between the specimen and die and point 3 is on the surface of

the die. In Fig.l (b), point 1 is at the border between the specimen and die and point 2 is at the

center of the sample and point 3 is at the 1/2 radius of the specimen and point 4 is on the surface of

the die.

a. Method One

4 • Pulse Electric Current Synthesis and Processing of Materials

Study on the Process Mechanism in Spark Plasma Sintering

b. Method Two

Fig.l. Schematic of temperature measurement points

2.3. Calculations and results

In one case we used the composite TiB2+BN (TiB2 is conductor and BN is an insulator), its

electrical conductivity can be adjusted by change the proportion of two phases. When the

conductivity of the sample equals to that of the graphite die, the calculated results of temperature

difference with heat-up can be seen in Fig. 2. When the heating- rate is 1.5 K/s, the temperature

difference between the center of the sample and the border point of the sample and the die is about

150 K, while the temperature difference between the inner side and the surface of the die is less

than 120 K. When the heating rate is 2.8 K/s, the temperature differences for the corresponding

two values are larger, up to 345 K and 220 K, respectively.

0 10 20 30 40

0

100

200

300

400

500

600

Semidiameter (mm)

Fig.2. Calculated of temperature fields

(From the center to 20mm is the sample TiB2-BN. and from 20mm to 45mm is the die)

I

Q -

1 I"

Pulse Electric Current Synthesis and Processing of Materials • 5

Study on the Process Mechanism in Spark Plasma Sintering

The results for a heating rate of 3 K/s are shown in Fig. 3. The measured results demonstrate

that the temperature difference between the center of the sample and the border can be as high as

450 K (when the sintering temperature at the center is about 1973 K), which is slightly higher than

the calculated result under a steady-state condition, because the temperature of the sample did not

reach a steady-state distribution. The temperature difference inside the die can reach 270 K.

2073

1873

1673

§ 1273

S

& 1073

B

H 873

673

473

273

0 100 200 300 400 500 600

Time (s)

Fig.3. Measured temperatures vs. heating timeüTiEb-BN, 3 K/sD

Fig.4 shows an SEM fracture surface images of the sintered TiB2-BN ceramics. As can be

seen, the grain size in the center of the sample is greater than that near its edge, which indicates

that temperature in the center of the sample is higher, having promoted significant grain growth

in the TÍB2-BN composite.

(a) Sample edge (b) Sample center

Fig.4. SEM of fracture surface of TÍB2-BN ceramics

When a metallic sample was used, e.g., Cu, the temperature difference in the sample is very

6 • Pulse Electric Current Synthesis and Processing of Materials