THE DEVELOPMENT OF COPPER ALLOY METALLURGY IN THAILAND IN THE PRE-BUDDHIST ...

513 Pages·2008·32.54 MB·English

V
Thanks are also due to my sister, Khanitta Rajpitak,
for drawing the maps of Thailand and the equilibrium dia-
grams, to Mr. Dorrell and Mr. Laidlaw of the Institute of
Archaeology Photographic Department for their advice, and
to Mrs. C. Coudrille who has kindly done all the layout
and typing of this thesis.
Most of all I should like to express my gratitude to
my supervisor, Dr. N.J. Seeley. I very much appreciate and
thank him for his constant support, encouragement and val-
uable advice. Without him this thesis would not have been
possible.
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CONTENTS
Volume I

1. Introduction 1

1.1 Geography of Thailand 2

2
1.2 Early prehistory

1.2.1 The Spirit cave 3

1.2.2 The Bayon cave 3

1.3 Later prehistory 4

1.3.1 Ban Kao 4

1.3.2 Kok Charoen (Lopburi. Province) 5

1.3.3 The Lopburi Artillery Centre site 5

1.3.4 Ban Chiang 6

1.4 Significance of dating evidence 7

1.5 Sites chosen for study 8

1.5.1 Kok Khon 8

1.5.2 Non Chai 8

1.5.3 Kok Makamtao 11

1.5.4 Noen Kiong Bamrung 11

1.5.5 Non Nok Tha 12

1.5.6 Ban Na Di 14

1.5.7 Ban Don Ta Phet 15

1.6 Previous work on metallurgy in Thailand 19

2. Experimental 24

2.1 Visual examination 24

2.2 X-radiography 24

2.3 Sampling technique for elemental chemical analysis 25

2.4 Solution preparation for chemical analysis 26
vii
2.5 Preparation of standard solutions for Atomic
Absorption and Induction Coupled Plasma Spectroscopy 28
2.6 Atomic Absorption Spectroscopy 29
2.7 Inductively Coupled Plasma Optical
Emission Spectroscopy 31
2.8 X-ray fluorescence 34
2.9 Metallography 35
2.9.1 Theory 35
2.9.2 sectioning of area to be examined 36
2.9.3 Mounting the specimens 37
2.9.4 Grinding and polishing 37
2.9.5 Etching 39
2.9.6 Examination of the specimen and
recording the structure 40
2.10 Experiments on the structures of quenched
standard alloys of high tin bronze 40
2.10.1 The preparation of standard alloys
of high tin bronze 40
2.10.2 Quenching of the standard alloys from
different temperatures 41
2.11 Microhardness test 42
2.12 Electron probe microanalysis 43
3. Microstructural characteristics 66
3.1 The metallographic structure of pure copper 66
3.1.1 The cast structure of copper 67
3.1.2 The microstructure of cold worked pure metal 68
3.1.3 The microstructure of hot worked pure metal 69
3.2 The binary alloy low tin bronze 69
3.2.1 The equilibrium diagram of the copper-tin
system, and phases occurring in the system 70
3.2.2 Microstructures commonly found in low
tin bronzes 74
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3.2.2.1 The as-cast structure 74
3.2.2.2 The cold worked structure 76
3.2.2.3 The hot worked structure 77
3.2.2.4 The heat treated structure 78
3.3 The binary alloy of high tin bronze 80
3.3.1 The 8-phase (high temperature) 84
3.3.2 The quenched structure in high tin bronze 86
3.3.2.1 Review of research on the martensitic
structure of high tin bronze 86
3.3.2.2 The microstructure of quenched high
tin bronze 93
3.3.2.3 The optical morphology of -martensite 98
3.3.2.4 Discussion of the similarities and the
differences between the present quenching
experiments on standard alloys and the
experiments by other researchers 100
3.3.2.5 Conclusion relating to the optical micro-
structures of beta martensites, and the
formation conditions of these martensites 102
3,4 Leaded bronze 105
3.5 Inclusions LOS
4. Microstructures found in ancient copper
alloy artifacts 107
4.1 Summary of the types of structure found in the
artifacts from Kok Khon 107
4.1.1 Containers 107
4.1.2 Bracelets 108
4.1.3 Rings 109
4.1.4 Arrowheads 109
4.1.5 Socketed axe 110
4.1.6 Coil of thin wire 110
4.1.7 Helically wound strip 110
4.1.8 Cast "false wire" helix 110
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4.2 Summary of the types of structure found in the
artifacts from Non Chal 111
4.2.1 Bracelet 111
4.2.2 Bracelet with bell 113
4.2.3 Bell 113
4.2.4 Large bell 114
4.2.5 Fragment of bronze vessel or large bell 114
4.2.6 Rings 114
4.2.7 Ornaments 115
4.3 Summary of the types of structure found in
artifacts from miscellaneous places in
North-East Thailand 115
4.3.1 Bracelets 115
4.3.2 Bead 117
4.3.3 Axe 117
4.3.4 Kettle-drum 118
4.4 Summary of the types of structure found in the
artifacts from Non Nok Tha 118
4.4.1 Bracelet 118
4.4.2 Ring 119
4.4.3 Fragment of blade 120
4.4.4 Fragments of bronze 120
4.4.5 Metal droplets 120
4.5 Summary of the types of structure found in the
artifacts from Ban Na Di 121
4.5.1 Cutting tools 121
4.5.2 Bracelets 121
4.5.3 Ring 122
4.5.4 Pendant 122
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4.6 Summary of the types of structure found In

objects from Ban Don Ta Phet 123

4.6.1 Containers and lids, including ladles 123

4.6.2 Bracelets 128

4.6.3 Rings 129
5. Catalogue
KOK KHON
(lab, no. 1001 et seq.) 131-163
NON CHAI
(lab, no. 1101 et seq.) 164-212
MISCELL1NEOUS SITES
(lab. no. 1901 et seq.) 213-249
NON NOK THA
(lab. no. 15001 et seq.) 2 50-344
BAN NA DI
(lab. no. 16001 et seq.) 345-42 3
BAN DON TA PHET
(lab. no. 18001 et seq.) 42 4-450
Summary of the types of artifact from Kok Khon 451
Summary of the types of artifact from Non Chai 452
Summary of the types of artifact from
miscellaneous sites 453
Summary of the types of artifact from Non Nok Tha 454
Summary of the types of artifact from Ban Na Di 455
Summary of the types of artifact from Ban Don
Ta Phet 456
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6. Conclusions 457
6.1 Raw materials 457
6.2 Extraction process 459
6.3 Alloying 459
6.3.1 Pure copper 472
6.3.2 Low tin bronzes 472
6.3.3 Leaded low tin bronzes 472
6.3.4 High tin bronzes 472
6.3.5 Leaded high tin bronzes 472
6.3.6 Brass 473
6.3.7 Lead-tin alloys 473
6.3.8 Antimony 474
6.4 Fabrication processes 474
6.4.1 Metal-working remains 474
6.4.2 Metal-working techniques 475
6.4.2.1 Lost wax casting 475
6.4.2.2 Fabrication techniques for high tin bronzes 476
6.4.2.3 Cold and hot working 477
6.4.2.4 Wire making 478
6.5 Artifact types 478
6.5.1 Containers 478
6.5.2 Personal Ornaments 478
6.5.3 Bells 478
6.5.4 Cutting tools 479
6.5.5 Miscellaneous objects 479
6.6 Chronology 479
6.7 Regional variation 480
6.8 Further work 481
BIBLIOGRAPHY 482
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LIST OF FIGURES
Fig - following page
1 Map of Thailand 2
2 Map of Prehistoric Sites in Thailand 8
3 Equilibrium di agram of the copper-tin system
(Raynor, 1944) 71
4 Equilibrium d iagram of the copper-tin system
(Smith, 1967) 72
5 Equilibrium diagram of the copper-t in system
(American Society for Metals, 1973) 73
6 Stable and metable phases in relation to the
s-phase of copper-tin alloy (Warliinont, 1965) 103
7 Part of the Cu-Sn phase equilibrium diagram show-
ing the variation of transformation behaviour with
alloy composition and quenching temperature
(Kennon and Miller, 1972) - 104
8 Map of mineral resources in Thailand 457
page
9 Histogram of Sn for the samples from all sites 460
10 Histogram of Pb for the samples from all sites 461
11 Histogram of Sn for the samples from Kok Khon 462
12 Histogram of Sn for the samples from Non Chai 463
13 Histogram of Sn for the samples from Non Nok Tha 464
14 Histogram of Sn for the samples from Ban Na Di 465
15 Histogram of Sn for the samples from Ban Don Ta Phet 466
16 Histobram of Pb for the samples from 1<0k Khon 467
17 Histogram of Pb for the samples from Non Chai 468
18 Histogram of Pb for the samples from Non Nok Tha 469
19 Histogram of Pb for the samples from Ban Na Di 470
20 Histogram of Pb for the samples from Ban Don Ta Phet 471
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LIST OF TABLES
Page
Table 1 Non Nok Tha Bronze (Bayard, 1981) 13
Table 2 Dating Material from Pimai, Thailand
(Carriveau, 1974) 22
Table 3 Concentration of Elements in the
Standard Solutions 46
Table 4 Metal Analyses by ICP and AA Spectroscopy 4 7-60
Table 5 The composition, annealing time at 750°C,
and quenching temperature of standard alloys 61
Table 6 Vickers hardness values of standard alloys 62-6 3
Table 7 Vickers hardness values of ancient specimens 64
Table 8 Hardness of high-tin bronzes in as-cast
condition and after heat treatment 65
Table 9 Mean value of trace elements in atifacts
from different sites in Thailand 459
Volumes II, III & IV
PLATES
In volumes II, III and IV, with references to the Catalogue.
1
1. INTRODUCTION
Earlier work on a group of copper alloy artifacts from
Thailand (Rajpitak, 1979) revealed metallurgy of a sophisti-
cation not previously known in South East Asia in the pre-
historic period. Further and more systematic work seemed
desirable, and the present thesis is based on material from
excavations carried out by the Thai Fine Arts Department
and archaeologists from outside Thailand who have made their
material available for study (see acknowledgements).
This thesis is an attempt to investigate the development
of copper alloy technology in Thailand, to correlate arti-
fact types with composition, to examine possible correla-
tions between alloy type and chronology, and finally, if it
is possible, to look for minor compositional differences which
might indicate local variations based upon ore type or
provenance. The materials studied are mostly from archaeo-
logical excavations in Thailand, although there are some
from surveys without full site details and some from private
donations to museums.
Work on Prehistoric Archaeology in Thailand is the sub-
ject of controversy, especially as to chronology. Insuffi-
cient excavations have been done even to fully understand
the sequence of prehistoric and early historic periods.
This thesis tries to document the development of metallurgy
between prehistoric and proto-historic periods in Thailand.