Electrical Properties of Annealed and Coated Boron Nitride Under Electron-Beam Irradiation
Résumé
The charging and relaxation kinetics of pyrolytic boron nitride (BN) substrates, boron nitridewith an aluminumoxide (BN∕Al2O3) coating, and thermally annealed alumina-coated boron nitride (an–BN∕Al2O3) were investigated under low-power electron irradiation (5 < incident energy E0 < 20 keV and incident flux Ji = 10 nA.cm−2 at room temperature) in the CEDRE (Chambre d'Etude De Revêtements Electrisés, in French) facility at ONERA–The French Aerospace Lab. Surface potentials of each ceramics configuration were measured over time using the Kelvin probe method. The influence of coating and annealing treatments to limit charging is discussed in this paper.Athorough study of an an–BN∕Al2O3 sample was carried out under a critical electron flux (E0 = 20 keV and Ji = 750 nA.cm−2) to assess the degradation kinetics of the material’s electrical properties. The characterizations of an–BN∕Al2O3 samples were performed before and after electrical aging at CIRIMAT (Centre Inter-universitaire de Recherche et d'Ingénierie des MATériaux, in French) to identify the structural and chemical evolution that would explain this degradation. A chemical deterioration of coating and some contaminants was observed after the critical irradiation.