航空刹车用炭/炭复合材料沥青浸渍法增密研究

以CVD工艺预增密至一定密度的自制刹车用炭/炭(C/C)复合材料和国外C/C复合材料刹车片为研究对象,分别采用中温沥青及高温沥青为浸渍剂,对C/C刹车片进行浸清-炭化新工艺补充增密处理.结果表明:自制及国外C/C刹车片均具有较好的可浸渍性;可以采用沥青浸渍-炭化法高效增密;两种沥青相比,高温沥青残炭率更高,但也易产生难石墨化炭;针对整个沥青而言的宏观残炭率与只针对样品而言的实际残炭率的差距随着炭化压力提高而变小,因而,为了快速制取C/C复合材料刹车片,必须提高炭化压力;新工艺补充增密后C/C复合材料刹车片样品各项性能比增密前均有显著的提高.

Analyses of densificating C/C composites used for aircraft brakes by coal-tar pitches impregnation and carbonization

The present paper studies the effect of carbonization pressure and different kinds of coal-tar pitcheson the densification efficiency and the graphizability of the CVD pre-densificated self-fabricated Carbon/Carbon (C/C) composites and Boeing 767 aircraft brakes. The results show that, liquid pitch impregna-tion-carbonization method is a suitable densification technology when the density of C/C compositee isabout 1. 60 g/cm~3 got by CVD technology before impregation. At the same time, the results also provethat carbon yield as a whole system, macro carbon yield, is higher than the carbon yield calculated byC/C composite specimen alone, so that high carbonization pressure is needed to get better densificationefficiency. Generally, the frictional and thermal properties of Boeing 767 and self-fabricated samples weregreatly improved after densification by pitch impregnation/ carbonization.