Table Of ContentEPO APPLIED TECHNOLOGY SERIES
OTHER TITLES IN THE SERIES
Volume 1 CARDON & FRANSEN Dynamic Semiconductor RAM Structures
Volume 2 LAMMINEUR & CORNILLIE Industrial Robots
Volume 4 HOORNAERT Reverse Osmosis
Volume 5 GEISLER et al Optical Fibres
Volume 6 JACOBS et al Nickel & Cobalt Extraction Using
Organic Compounds
Volume 7 CRISTOL Solid State Video Cameras
Volume 8 CORNILLIE & DAVES Microprocessors
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Inorganic Fibres
and
Composite Materials
A Survey of Recent Developments
P. BRACKE, H. SCHURMANS
and
J. VERHOEST
European Patent Office, The Hague, The Netherlands
Pergamon International Information Corporation
a member of the Pergamon Group
PERGAMON PRESS
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Copyright © 1984 Commission of the European Communities
A11 Rights Reserved. No part of this publication may he reproduced,
stored in a retrieval system or transmitted in any form or by any means:
electronic, electrostatic, magnetic tape, mechanical, photocopying,
recording or otherwise, without permission in writing from the
copyright holders.
First edition 1984
Reprinted 1985, 1986
Library of Congress Cataloging in Publication Data
Brackc, P.
Inorganic fibres & composite materials.
(EPO applied technology scries ; v. 3)
1. Inorganic fibres. 2. Fibrous composites.
I. Schurmans, 11. II. Vcrhocsl, J. III. Title.
IV. Title: Inorganic fibres and composite materials.
V. Series.
TS1549.A1B73 1984 666'.8 83-25736
British Library Cataloguing in Publication Data
Brackc, P.
Inorganic fibres & composite materials.—
(EPO applied technology series; no. 3)
1. Textile fibres, synthetic
I. Title II. Schurmans, H.
III. Verhocst, J. IV. Scries
677'.4 TS1548.5
ISBN 0-08-031145-8
Printed in Great Britain by A. Wheaton & Co. Ltd., Exeter
Preface
This monograph aims to present a timely summary of the recent developments
in the field of inorganic fibres and composite materials, as it emerges from
the published patent and non-patent literature incorporated in the systematic
documentation of the EPO at The Hague (Netherlands).
Said study covers in principle the period from 1970 up to now, but as an
introduction to each chapter a comprehensive but concise survey of the state
of the art prior to that period is provided, accompanied by ample though not
exhaustive references to patents, periodicals or books.
Where possible an indication of the expected trend concludes each chapter.
Although not limited to that country, special attention has been given to
progress achieved in Japan.
The monograph contains two major parts; a first one dealing with the
composition, preparation and specific treatment of the fibres, while a second
part concerns their use in the manufacture of high grade composite materials.
Part one embraces, in principle, all types of artificial inorganic fibres
with the exception however of glass fibres; due to their specific nature,
properties and methods of manufacture, glass fibres are part of a quite
distinct technological field and should be dealt with in a separate
monograph.
On the other hand, monocrystalline fibres (e.g. whiskers) are included in the
present study; development of that type of fibre competed during the last
decade with the progress in continuous filament technology, especially for
obtaining composite materials with exceptional characteristics.
Due to their particular methods of preparation they are treated in a
separate chapter of Part one.
Specific entries are furthermore provided for the most important types of
fibres known up to date; for each type the following aspects are to be
discussed : manufacture, post-treatments, properties and uses.
Part two is limited to entirely inorganic materials, i.e. the matrix as well
as the reinforcing fibres being inorganic. An extension to the extremely vast
field of the fibre reinforced resins would increase the size of the present
monograph out of proportion and seriously affect its clarity.
Fibre reinforced plastics should thus constitute the subject of a separate
monograph.
More detailed information on the scope of a particular item will be given in
said item.
v
This study has been made for the Commission of the European Communities,
DG XIII - Information Market and Innovation, Division Technological
Information and Patents.
Note on Cited Patent
Documents
In this monograph, a great number of patents and published patent
applications* are cited, using an international two-letter country code, i.e.:
DE = Germany (Federal Republic)
EP = European Patent Office
FR = France
GB = United Kingdom
JP = Japan
[all cited documents** are
published patent applications
(KOMI TOKKYO)]
SU = USSR
US = United States of America
WO = International Bureau of W.I.P.O.
(PCT-applications)
Whenever corresponding patent documents have been found, they are indicated
preceeded by an "=" sign.
* The patent literature covered by the search files of the European Patent
Office at The Hague (Netherlands) encompasses patent publications of
following countries or offices : Australia, Austria, Canada, France,
Germany (Federal Republic), Japan, Switzerland, United Kingdom, USA, USSR,
European Patent Office (EPO), World Intellectual Property Organization
(W.I.P.O.), African Intellectual Property Organisation (OAPI), Belgium,
Luxembourg, The Netherlands.
** The KOKAI TOKKYO's numbers begin actually with two digits indicating the
year of publication in the Japanese system', we have replaced that
indication by the occidental (gregorian) year; the Japanese year equal to
the gregorian minus 25.
Example : Japanese # 52. 84122 is cited as 77. 84122.
xi
PART I
INORGANIC FIBRES
THEIR MANUFACTURE
AND PROPERTIES
NOTES ON CONTENTS
This part covers artificially made, inorganic fibres with the exception
of glass fibres.
Only these processes are considered that permit zhe productica of fibrous
material that can be recovered as such. In-situ growing of fibres in
matrices is dealz with in Part II, page 226.
All fibres showing a mono crystalline struczure are included in Chapter
irrespective of z::eir nazure or chemical composizion.
3
4 INORGANIC FIBRES
Obtaining small diameter filaments
by drawing matrix encased preforms
CHAPTER 1
Metal Fibres
1. Summary of the Prior Art
Metal fibres which are to be used as reinforcing elements in composite
materials should possess specific mechanical and physical properties such as
high tensile strength and elasticity modulus, low density, appropriate thermal
expansion coefficient and stability against dissolution by, or chemical
reaction with, the matrix material. Such properties are chiefly determined
by the composition and the metallurgical structure of the fibre material,
the latter being in turn governed by the manufacturing process and the
thermal or thermomechanical treatment of the wire product.
The present chapter will only deal with the development of the relevant
manufacturing processes.
Among the many metals which have been investigated as to their strengthening
ability in different matrix materials, only filaments of the refractory
metals titanium, tungsten, tantalum and molybdenum and filaments of beryllium,
steel and some superalloys were found to have an acceptable combination of
the required properties. These filaments are generally fabricated by one of
the following techniques:
yir?_rr?y±-I_5§5t!Digy?E' This conventional, well known method has
been used for the production of fibres of nearly all of the above mentioned
metals and proved to be satisfactory. But production costs as well as
problems of wire breakage, which rise very rapidly with decreasing filament
thickness, are the limiting factors in the production of filaments or fibres
with diameters below 100u.
Smaller diameters down to 1(L or even less have been obtained by encasing a
core wire within a sheath or matrix of a ductile sacrificial material, drawir?
the whole to a predetermined cross section and removing the sheath material
by etching. This technique is advantageously used for the simultaneous
drawing of a plurality of filaments (1).
In an analogous embodiment metal material was sheated with a glass or
ceramic envelope, heated to a temperature sufficient to soften the sheath
material and to melt or soften the metal core and drawing the whole while in
plastic state. By using high frequency heating very fine wires of high
melting metals could be obtained (2)(3)(4).
1.2. ^elt_formir.g_technigues. Metal melts have a very low viscosity which
excludew priori'direct fibre drawing from the melt. On the other hand their
relatively high surface energy which often exceeds the viscosity, makes the
production of filaments by extrusion or casting of a melt very problematic
5
