Ablation behavior of boron nitride based ceramic composites reinforced by continuous silicon oxynitride fiber

摘要

Continuous silicon oxynitride fiber reinforced boron nitride matrix (Si-N-O-f/BN) composite has been recognized as a promising microwave transparent radome material. In the present study, the ablation behavior and properties of the Si-N-O-f/N composites under an oxyacetylene torch ablation environment were investigated. The average linear and mass ablation rates of the composites decreased with the increasing of the fabrication temperature and were 0.132 mm s(-1) and 0.057 g s(-1) for the 1200 degrees C fabricated composites. The ablation products mainly consisted of glassy SiO2 and B2O3, and highly crystallized BN. The ablation center involved three different actions: decomposition of the Si-N-O fibers and sublimation of the BN matrix, oxidations of the matrix and the reinforcing fibers, and thermal treatment of the BN matrix beneath the covering SiO2 film. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.