Ceramic Matrix Composites:<scp>CVI</scp>(Chemical Vapor Infiltration)

Leuchs, M.

doi:10.1002/9781118097298.weoc030

Cited by 3 publications

(2 citation statements)

References 47 publications

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“…[77]. Because of its low efficiency, this method is mainly used to prepare thinner structural composites or membrane materials or as an auxiliary densification method [78].…”

mentioning

confidence: 99%

Toughening Mechanism of Mullite Matrix Composites: A Review

Cui

Zhang

et al. 2020

Coatings

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Mullite has high creep resistance, low thermal expansion coefficient and thermal conductivity, excellent corrosion resistance and thermal shock resistance, and plays an important role in traditional ceramics and advanced ceramic materials. However, the poor mechanical properties of mullite at room temperature limit its application. In order to improve the strength and toughness of mullite, the current research focuses on the modification of mullite by using the second phase. The research status of discontinuous phase (particle, whisker, and chopped fiber) and continuous fiber reinforced mullite matrix composites is introduced, including preparation process, microstructure, and its main properties. The reinforcement mechanism of second phase on mullite matrix composites is summarized, and the existing problems and the future development direction of mullite matrix composites are pointed out and discussed.

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“…[77]. Because of its low efficiency, this method is mainly used to prepare thinner structural composites or membrane materials or as an auxiliary densification method [78].…”

mentioning

confidence: 99%

Toughening Mechanism of Mullite Matrix Composites: A Review

Cui

Zhang

et al. 2020

Coatings

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“…Advantages of using CVI to create the matrix phase include a matrix phase built up and adhered closely to the fibre structure, little chance of poisoning the FMI, tight control over the matrix microstructure, and the ability to create layered multi-phase matrices. Disadvantages to CVI include long processing times, the need to use machining to re-open the pore networks, residual porosity, expensive equipment, and limited matrix compositions [10].…”

Section: Chemical Vapour Infiltrationmentioning

confidence: 99%

Design, Manufacturing, and Characterization of a Novel Ceramic Matrix Composite

Robertson¹

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A novel ceramic matrix composite (CMC) system consisting of a commercially available SiC fibre, variations of electrophoretically deposited (EPD) fibre-matrix interphases, and a liquid metal melt infiltrated matrix was designed and characterised. A factorial design of experiments approach was undertaken to evaluate the deposition variables which would result in a functioning fibre-matrix interphase.A 2 5-2 partial factorial design matrix was selected with factors: electric potential, deposition time, surfactant, binder, and solids loading. The design matrix was replicated for four different EPD fibre-matrix interphase coating combinations: Al2O3/SiC, BN/PSZ, ZrC/ZTA, and SiC/Si3N4/SiC. Microcomposites were evaluated for tensile properties using a standard displacement controlled tensile test program.Microcomposites were tested at room temperature immediately following fabrication and following exposure to a standard atmosphere at 1000 °C for 1 h. Samples with ZrC/ZTA and SiC/Si3N4/SiC coatings demonstrated the best tensile properties in room temperature tests while samples with BN/PSZ and SiC/Si3N4/SiC coatings demonstrated the best retention of tensile properties following high temperature exposure. Subsequent SEM analysis revealed that coatings with smaller particle diameters as the inner layer of the fibre-matrix interphase coating produced more uniform coatings and the less fibre degradation due to oxidation following high temperature exposure. Additional microcomposites were fabricated for high temperature tensile testing; however, these samples were unable to bear recordable loads, an SEM examination revealed significant degradation of the matrix phase beneath the high temperature adhesive.Optical microscopy was used to evaluate coating thicknesses of coated fibre bundles prior to heat treatments. Measured coating thickness indicated that generally higher deposition times resulted in thicker coatings; however, coatings produced using 25 V electric potential were thicker than coatings produced using 12.5 V and 50 V electric potentials. This is likely due to a greater deposition efficiency factor at 25 V. FEA analysis was used to evaluate the electrical properties of an idealized version of the stationary EPD cell. This analysis showed a significant variation in the electric field along the fibre axis as well as a significant variation in electrical field between fibres in the centre of the fibre bundle and on the outer edge of the fibre bundle.

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