Termoplasticos

Thermochemical Processes
Principles and Models

Thermochemical Processes
Principles and Models
C.B. Alcock DSc, FRSC

OXFORD AUCKLAND

BOSTON JOHANNESBURG MELBOURNE NEW DELHI

Butterworth-Heinemann Linacre House, Jordan Hill, Oxford OX2 8DP 225 Wildwood Avenue, Woburn, MA 01801-2041 A division of Reed Educational and Professional Publishing Ltd

First published 2001
 C.B. Alcock2001
All rights reserved. No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or underthe terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England W1P 9HE. Applications for the copyright holder’s written permission to reproduce any part of this publication should be addressed to the publishers

British Library Cataloguing in Publication Data Alcock, C. B. Thermochemical processes:principles and models 1 Thermodynamics 2 Chemicalprocesses temperatures I Title 660.20 969

3 Materials at high

Library of Congress Cataloguing in Publication Data Alcock, C. B. Thermochemical processes:principles and models/C.B. Alcock. p. cm. Includes bibliographical references. ISBN 0 7506 5155 5 1 Thermodynamics 2 Chemical processes 3 Materials at high temperatures I Title TP155.2.T45 T47 2000 00-049367 6600 .2969–dc21 ISBN 0 7506 5155 5Typeset by Laser Words, Chennai, India Printed in Great Britain

Contents

Preface

xi 1

Part 1: Processes with gaseous reaction control

1 Vapour deposition processes 3 Vapour deposition for the preparation of thin films 3 Vapour pressure data for the elements 4 The kinetic theory of a gas in a container 4 Molecular effusion 6 Vapour deposition of elements 6 The deposition rate on acool substrate 8 Vapour deposition of alloys 8 Vapour deposition of compounds 10 Free evaporation coefficients of solids 11 Other techniques for the preparation of thin films 16 Single and epitaxial films in semiconducting systems 16 Thin film production by the sputtering of metals 17 The production of nanoparticles 20 Coating with thin diamond films 22 Plasma evaporation and pyrolysis of carbon to formFullerenes Materials science and the formation of thin films 24 The formation of nuclei from the vapour phase 24 The formation of a film from nuclei 28 Grain growth in the initial deposit 30 Point defects in solids 31 Edge and screw dislocations 33 Interfacial energies in solid systems 35 Bibliography 38 Appendix: Vapour pressure data for the elements 38 2 Gaseous reaction kinetics and moleculardecomposition Theories of reaction kinetics 42 Thermal energies and the structures of molecules 43 The collision theory of gaseous reactions 45 Transition state theory of gaseous reactions 47 Empirical estimates of the activation energy 49 The order of chemical reactions 50 42

23

vi

Contents

Time dependence of the extent of reaction 52 Chain reactions 52 Combustion chain reactions 53Chain reactions in the combustion of gaseous fuels 56 Fuel/air mixing in combustion systems 58 The thermal efficiencies of combustion engines 59 Bibliography 62 Molecular dissociation and chain reactions in chemical vapour deposition 62 Thermochemical data for the dissociation of gaseous molecules 63 Bond character in gaseous heteronuclear compounds 64 Hybridization of covalent bonds 66 Bond energiesof gaseous polyvalent metal halides 67 Thermal decomposition of hydrides and organometallic compounds 68 Bibliography 71 Radiation and electron decomposition of molecules 72 Photochemical reactions 73 Dissociation cross-sections 75 Substrate heating by transmitted radiation 77 Radiation and convection cooling of the substrate 82 Laser production of thin films 82 Molecular decomposition in plasma...