Ablation Properties of C Fibers and SiC Fibers Reinforced Glass Ceramic Matrix Composites Upon Oxyacetylene Torch Exposure

Julien Beaudet,Jonathan Cormier,Magali Rollin,André Dragon,Guillaume Benoit

doi:10.4236/msa.2011.210189

Abstract

The ablation properties of two laminated composites, having both a glass ceramic matrix and different kinds of fibers (C or SiC) with the same architecture, are evaluated and compared. Ablation tests are performed using an oxyacetylene torch on samples having two different thicknesses. Mass loss and ablation depth are measured after flame exposure. The results obtained show that the decomposition of SiC fibers during thermal exposure has a significant impact on ablation behavior. Oxidation of SiC produces a liquid SiO2 film at the top of the material during ablation. This leads to an improved ablation resistance compared to the glass ceramic matrix/C composite, especially in case of successive flame exposures where the SiO2 film consumes a substantial fraction of the heat flow during its liquefaction upon re-heating.

Highlights

Ceramic matrix composites are widely used for many engineering applications concerning severe loading conditions including ballistic context or re-entry of space vehicles
Oxidation of SiC produces a liquid SiO2 film at the top of the material during ablation. This leads to an improved ablation resistance compared to the glass ceramic matrix/C composite, especially in case of successive flame exposures where the SiO2 film consumes a substantial fraction of the heat flow during its liquefaction upon re-heating
A progressive and limited (1% at the maximum) mass loss is observed until a plateau is reached at approximately 750 K for both materials

Summary

Introduction

Ceramic matrix composites are widely used for many engineering applications concerning severe loading conditions including ballistic context or re-entry of space vehicles. For such applications, the material degradation mainly results from aerodynamic impact involving intense mechanical and thermal loading. High thermal resistance of the corresponding material is required against short intense thermal and mechanical load. Regarding flying structures, one of the primary design criteria is the mass gain. In this respect, increasing ablation resistance for protective structures of limited mass is an obvious technical challenge for spacecraft–related research and development [1]

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Conclusion