Ceramics matrix composites (CMCs) can retain their mechanical strength even at high temperatures and are lighter than superalloys. Such properties make them interesting candidates to address current challenges in aerospace and energy sectors. Frequently, the final component is manufactured by integrating CMC parts with others made of the same material or a different one (often metals). Thus, joining is a critical operation for manufacturing reliable products. 
Surface preparation is has a crucial role in improving the quality of the joints. In particular, surface texturing can create a mechanical anchoring system (interlocking) when infiltrated by the bonding agent, thus increasing the mechanical strength of joined structures.
 
The high hardness of CMCs makes it difficult and expensive to provide surface texturing through mechanical machining. Other tools have the potential to address this operation more effectively like laser and plasma treatments. Furthermore, atmospheric-pressure plasmas are of particular interest to industry because of their versatility, since they do not require a vacuum system.
In the work hereby presented non-oxide composites were plasma-treated prior to joining operations in order to evaluate the contribution given by the treatment on the final joint strength. The plasma proposed for this application is an atmospheric-pressure plasma jet (APPJ) and the target materials were carbon fiber-reinforced carbon (C/C) and carbon fiber-reinforced silicon carbide (C/SiC).
The evolution of the surface was evaluated, with a focus on the structure of the plasma-induced texture, the increase in the surface area, and the effect that the braze has on the wettability of the solid substrate. Then APPJ conditions were chosen and applied to surfaces to be joined in order to evaluate their effect on the joined strength. Joints were manufactured using reactive brazing alloys and then mechanical tested.
 
The effectiveness of the APPJ as a technique for surface texturing of C/C and C/SiC is presented by evaluating the influence that the new plasma-induced surface has on the mechanical properties of joints.