Oxidation resistance in air of 1-D SiC (Hi-Nicalon) fibre reinforced silicon nitride ceramic matrix composite
The oxidation behaviour of a Si(3)N(4) matrix reinforced with SiC fibres (Hi-Nicalon) precoated with a 400 nm thick pyrolytic carbon layer has been investigated in dry air in the temperature range 800 C to 1500 C. The same study was performed for individual constituents of the composite (fibre and matrix). Two phenomena are observed in the oxidation behaviour of the composite. At low temperature (T less than 1200 C), the matrix oxidation is negligible, only the carbon interphase was oxidised creating an annular space between the fibres and the matrix throughout the sample. At high temperature (T at least 1300 C) the rate of formation of the oxidation products of the matrix is rapid and a sealing effect is observed. While at these temperatures the interphase is protected in the bulk of the material, the time needed to seal the gap between the fibre and the matrix is too long to prevent its oxidation to a significant depth from the surface. Finally, preliminary results are presented where the consumption of the interphase is completely prevented by applying an external coating which gives oxidation protection from low to high temperature.
Bibliographic Reference: Paper presented : 4ième Colloque International sur la Corrosion et la Protection, Les Embiez (FR), 20-24 May 1996
Availability: Available from (1) as Paper EN 39918 ORA
Record Number: 199610927 / Last updated on: 1996-09-16
Original language: en
Available languages: en