Oxidation protection of C/Si–C–N composite by a mullite interphase

A comparative study of Si–C–N films on different substrates grown by RF magnetron sputtering

“…They are produced in bulk form by pyrolysis of organometallic polysilazane precursors, where polymer to ceramic transformation takes place [11,13,14]. The polymer impregnation and pyrolysis (PIP) process was used to prepare a mullite interphase of C/Si-C-N composites in order to provide an acceptable oxidation protection of these composites [15].…”

Influence of the Si–O–C interlayer on the oxidation behaviors and mechanisms of composites

“…It is believed that the weak interfacial bond of C/Si-O-C/Si-C-N will be another contribution to the enhancement of the oxidation resistance. For the composites with no interlayer or with tight interfacial bonding, such as C/Si-C-N and C/Mullite/Si-C-N in Lu et al [6], their matrix cracks usually extend to the surface of carbon fibers. When the composites were exposed to the elevated temperature in air, the air will directly diffuse along the crack to carbon fiber and reacts with it as described in Figure 11(a).…”

“…[5] Our previous results show that the mullite interphase could also enhance the oxidation resistance of the composite, strong interface bonding, lower microcrack density, higher coefficient of thermal expansion (CTE) of interphase, and thicker interlayer contributing to the improvement of oxidation resistance. [6,7] Si-O-C is another interphase material that could improve the oxidation resistance of the composite. But from Lu and Jiao [8], we can see that the Si-O-C interphase does not exhibit the high CTE, and the interface bonding of the composite is also weak.…”

Oxidation Behaviors and Mechanisms of C/Si–C–N with a Mullite Interlayer

“…Mullite interphase was prepared via a polymer impregnation and pyrolysis (PIP) process using the mixture of aluminium sec-butoxide (A1(OBu) 3 ) and tetraethoxysilicate (TEOS) as the starting materials. The details about the preparation of the mullite interphase were described elsewhere [10,11]. The carbon interlayer was deposited at 900 • C for 2 h using propene as precursor.…”

“…So far, the mullite had been used as an interlayer of C/Si-C-N composite and can greatly improve the oxidation resistance of composites [10]; but the oxidation behaviors and mechanisms of C/Si-C-N with a mullite interlayer are still unclear.…”