Dey, A and Chatterjee, Minati and Naskar, Milan Kanti and Basu, K (2003) Near-net-shape fibre-reinforced ceramic matrix composites by the sol infiltration technique. Materials Letters, 57 (19). pp. 2919-2926. ISSN 0167-577X

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Abstract

The infiltration of a ceramic fibre preform by a ceramic sol is a cost-effective method for the manufacture of ceramic matrix composites (CMCs). The ceramic sol after calcination forms the matrix and the discontinuous fibres act as the reinforcement agents. In this paper, a technique has been presented in which discontinuous mullite preform with 15 vol.% of fibre content was infiltrated with the stabilized zirconia-yttria (ZrO2.10 wt.% Y2O3) sol to fabricate near-net-shape CMCs. The effects of sol viscosity, number of infiltration, in situ deposition of carbon in the CMC samples, and calcination (in air and nitrogen atmosphere) temperature on physico-mechanical properties of fabricated CMCs were examined. The characterization of the preform and the developed CMCs were performed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD indicated the presence of both cubic (c) and tetragonal (t) zirconia in the CMCs calcined even at 1400 degreesC. The flexural strength of the CMCs (calcined in air at 1400 degreesC) when determined by the three-point bend test was found to be almost 14 MPa under a given set of experimental conditions, while calcination of the same materials at 1400 degreesC in nitrogen atmosphere (carbon-containing CMCs) exhibited a modulus value of almost 51 GPa. SEM indicated multiple fractures of the matrix, which gave rise to pseudo-ductility. This is also evident from the load-elongation curve of the three-point bend test. The reinforced fibres acted as crack arresters, which prevented the propagation of the cracks. SEM studies also indicated fibre pull-out in the fracture surface of the CMCs. (C) 2003 Elsevier Science B.V, All rights reserved.

Item Type:	Article
Uncontrolled Keywords:	Sol-gel preparation; Composite materials; Vacuum infiltration; Preforms
Subjects:	Engineering Materials
Divisions:	UNSPECIFIED
Depositing User:	Subhra Lahiri
Date Deposited:	21 Feb 2012 09:54
Last Modified:	21 Feb 2012 09:54
URI:	http://cgcri.csircentral.net/id/eprint/880

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