Boron-bearing species in ceramic matrix composites for long-term aerospace applications

Boria Effects on the High Temperature Oxidation of Silicon Carbide

“…Another study by Naslain et al showed that during static fatigue testing of BNcoated fibers, the cracks present on fiber surfaces were filled in by the borosilicate glass, which afforded better fiber oxidation resistance than if the cracks were unsealed 4 Figure 6 A, but also determined that the pore sizes ranged from 4 -9 membered rings, as annotated in Figure 6 The v-SiO2 structure is stable up to temperatures < 1300˚C, whereupon it transforms into crystalline β-cristobalite 45 . Cristobalite is comprised of uniform 6-membered rings 44 .…”

Composites, Multifunctional

“…By coating the fibers with carefully selected materials, the oxidation can be controlled and result in self-healing of the micro-cracks. Graphitic carbons ("py rocarbons," "PyC") and boron nitride (BN) have emerged as the most prominent interphase [39,44,70,71,72]. When oxygen diffuses through the micro-cracks, a fluid oxide is formed due to the oxidation, filling the cracks, Fig.…”

High temperature self-healing SiBCN ceramics derived from hyperbranched polyborosilazanes

“…In this field, the selfhealing behavior of various ceramics such as silicon carbide (SiC)/mullite [15,16], SiC/Al 2 O 3 [17,18], and C f /SiC ceramic matrix composites can be achieved by introducing hightemperature oxidation additives or boron-containing additives [19][20][21], such as silicon dioxide (SiO 2 ) [22], alumina (Al 2 O 3 ) [23,24], and boron carbide (B 4 C) [25]. The crack healing is mainly attributed to the formation of protective oxide film in the damaged area in ceramics or composites.…”