Active control of the anisotropic wettability of the carbon fiber reinforced carbon and silicon carbide dual matrix composites (C/C-SiC)

Anisotropic wettability characterizes the surfaces of the carbon fiber reinforced carbon and silicon carbide dual matrix composites (C/C-SiC), because the surfaces are composed of different fiber endings. The aim of this investigation is to establish control over the anisotropic wettability on C/C-SiC surfaces. The influence of the groove density on the droplet contact angles (surface wettability) was investigated both on the circle fiber ending surfaces and on the pillar fiber ending surfaces. Based on the groove density, the 14 specimens were divided into 7 groups. Each group was composed of a circle ending surface and a pillar ending surface. Comparison of the droplet contact angles was also established within each group. The results showed that the droplet contact angles were decreased after laser treatment. The droplet contact angles also decrease with the increase of the groove density. The differential of the droplet contact angles within each group was narrowed after laser treatment. The hypothesized explanations were proposed for the observed phenomenon. Some fibers initially covered by the SiC matrix were re-exposed on the groove side wall. The variety of the fiber ending distribution on the groove side wall could possibly introduce a more efficient control over the surface wettability. This method can be extended to optimize the surface wettability and to eliminate the anisotropic effects of the fiber reinforced composites.