Chemical vapor infiltration: modelling solid matrix deposition for ceramic composites reinforced with layered woven fabrics

A model is developed for chemical vapor infiltration in a sample of overlapping, woven plies. The holes through each ply, formed by the interweaving of filamentous tows, are considered to be staggered maximally for the overlapping plies. The results are compared with another bounding case, the aligned-hole model studied previously. The staggered-hole model predicts concentration profiles, deposition amounts, porosities, and changes of dimensions with time. The model also explains the effects of diffusion, rate of deposition, and spatial distribution of filaments in the woven fabric. Staggering the holes leads to somewhat less uniform deposition in the holes between tows and in the spaces between plies.