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Title: Measurement of gas transport properties for chemical vapor infiltration

Technical Report ·
DOI:https://doi.org/10.2172/441120· OSTI ID:441120
;  [1]
  1. Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Engineering

In the chemical vapor infiltration (CVI) process for fabricating ceramic matrix composites (CMCs), transport of gas phase reactant into the fiber preform is a critical step. The transport can be driven by pressure or by concentration. This report describes methods for measuring this for CVI preforms and partially infiltrated composites. Results are presented for Nicalon fiber cloth layup preforms and composites, Nextel fiber braid preforms and composites, and a Nicalon fiber 3-D weave composite. The results are consistent with a percolating network model for gas transport in CVI preforms and composites. This model predicts inherent variability in local pore characteristics and transport properties, and therefore, in local densification during processing; this may lead to production of gastight composites.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Engineering
Sponsoring Organization:
USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
DOE Contract Number:
AC05-96OR22464
OSTI ID:
441120
Report Number(s):
ORNL/Sub-87-00184/06; ON: DE97051435
Resource Relation:
Other Information: PBD: Dec 1996
Country of Publication:
United States
Language:
English