[THESIS DEFENSE] - RM2I - Pierre Polette

Mme Nadia PELLERIN

Rapportrice

CEMHTI Orléans

M. Francis REBILLAT

Rapporteur

LCTS Bordeaux

Mme Cyrille MERCIER

Examinatrice

CERAMATHS Maubeuge

M. Daniel CAURANT

Examinateur

IRCP Paris

M. François MEAR

Directeur de thèse

UCCS Lille 

M. Lionel MONTAGNE

Co-directeur de thèse

UCCS Lille

Mme Fanny ALOUSQUE

Encadrante industrielle

Safran Landing Systems

oxidation protection system, carbon/carbon composite, aluminophosphate, silicate diffusion barrier

This PhD thesis, conducted in collaboration between Unit of Catalysis and Solid State Chemistry (UCCS) and Safran Landing Systems (SLS), focuses on the development of a new oxidation protection system (OPS) for carbon/carbon (C/C) composites used in aircraft braking systems. The proposed approach combines an amorphous silicate phase with an aluminophosphate one. This OPS is obtained from a precursor suspension, followed by a thermal treatment. We first investigated the formation and interaction of different phases by NMR spectroscopy, revealing a phosphate-induced segregation of modifiers that promotes the formation of a highly polymerized silicate network. The influence of composition and thermal treatment on the resulting phases was characterized. We then looked at the interaction of the OPS with the oxidation catalysts. The thermal behaviour of the OPS within the C/C composite was then evaluated, showing a significant impact of the carbon on the stability of the protection. Finally, X-ray tomography was used to assess the oxygen barrier performance, especially the volumetric filling of the carbon/carbone porosity.