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Microwave enhanced chemical vapour infiltration of silicon carbide fibre preforms

D'Angio', Andrea (2018)
Ph.D. thesis, University of Birmingham.

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Abstract

An investigation into the fundamentals of the deposition of silicon carbide within porous silicon carbide fibre preforms using microwave-enhanced chemical vapour infiltration has been carried out. The study of the kinetics of deposition revealed an Arrhenius behaviour of the matrix growth rate against the temperature in the range 800-1000°C and a linear dependence on the pressure in the range 20 - 70 kPa. This is typical of a surface-reaction limited regime. The morphology of the SiC deposited changed with both temperature and pressure. Increases in both lead to a transition from a smooth, globular deposit morphology to something that was rougher and more angular; this corresponded to the transition from a nucleation to a growth regime. Stoichiometric SiC was predominantly found in the central region of the samples infiltrated at 1000°C, but the deposit became more silicon-rich (up to 2.6 at %) the farther from the initial deposit. Dielectric properties showed that ZMI Tyranno silicon carbide fibres readily absorbed microwave energy. In specific conditions of temperatures and pressures, 900-950°C and 50 kPa, an inside-out deposition pattern was observed indicating a temperature gradient across the preform. Deposition of silicon carbide and silicon caused the gradual flattening of the temperature gradient.

Type of Work:Ph.D. thesis.
Supervisor(s):Binner, Jon
School/Faculty:Colleges (2008 onwards) > College of Engineering & Physical Sciences
Department:School of Metallurgy and Materials
Additional Information:

Publication:

D’Angio, A., Zou, J., Binner, J., Ma, H. B., Hilmas, G. E., and Fahrenholtz, W. G., Mechanical properties and grain orientation evolution of zirconium diboride-zirconium carbide ceramics. Journal of the European Ceramic Society, 2018. 38(2), 391-402; http://dx.doi.org/10.1016/j.jeurceramsoc.2017.09.013

Keywords:Ceramic matrix composites, silicon carbide, chemical vapour infiltration, microwaves
Subjects:TN Mining engineering. Metallurgy
Institution:University of Birmingham
ID Code:8188
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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