Nozzle extensions made of ceramic matrix composites (CMCs) have shown the potential to replace heavy superalloy nozzles and improve the performance of future upper‐stage and orbital rocket engines. Gas permeability has been reported to be a critical issue during the manufacture for CMC nozzles. This work shows the manufacture of a dense radiation‐cooled C/C‐SiC nozzle demonstrator. A multi‐angle fiber architecture was applied using filament winding technique to reduce the incidence of delaminations during the manufacturing process under high temperatures. Additional efforts were made to improve the final gas tightness and reduce the amount of residual silicon by means of an adapted liquid silicon infiltration process. The manufacture, the material, and structural characterization as well as a finite element analysis of a performed internal pressure test are presented.

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The understanding of the directional dependence of electrical properties in composite materials is essential to develop an accurate electromechanical model for these materials. However, determining the out-of-plane electrical resistivity in composite materials is a challenging task due to the architectural complexity of these materials and the different electrical conductivity of the composite constituents. Moreover, the small thickness of most CMC panels imposes physical difficulties on measuring the out-of-plane electrical resistivity directly. This work provides an indirect method for determining the out-of-plane electrical resistivity for composite materials while introducing the concept of length constant. This method was utilized and successfully verified for three ceramic matrix composite systems with significantly different electrical properties. The proposed method can potentially be employed for other composite systems with conductive phases. K E Y W O R D S ceramic matrix composites (CMCs), electrical properties, non-destructive evaluation techniques, resistivity