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Armor‐grade B4C and SiC specimens were analyzed for phase assemblage, microstructure, and mechanical properties. SiC–N showed the highest four‐point fracture strength, and an ∼50% higher notched beam fracture toughness than solid‐state sintered B4C and SiC. This was attributed to preferential crack propagation along a weaker amorphous aluminosilicate grain‐boundary interphase, which also attenuated the effect of surface flaws on bending strength. Verco B4C showed the highest hardness. That material was phase pure, fully dense, and of finer grain size as compared with pressure‐assisted densification (PAD)‐B4C (hot pressed). Verco SiC showed a hardness equal to (Vickers) or higher than (Knoop) PAD‐B4C, and a comparatively narrow distribution in measured hardnesses. This was attributed to a fine‐grained, fully dense, solid‐state sintered microstructure with a fine and well‐distributed graphite second phase. Hardness of all specimens decreased with increasing applied load.

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In this study, we explore the use of atmospheric pressure plasmas for enhancing the adhesion of SiC surfaces using a urethane adhesive, as an alternative to grit-blasting. Surface analysis showed that He-O2 plasma treatments resulted in a hydrophilic surface mostly by producing SiOx. Four-point bending tests and bonding pull tests were carried out on control, grit-blasted, and plasma-treated surfaces. Grit-blasted samples showed enhanced bonding but also a decrease in flexural strength. Plasma treated samples did not affect the flexural strength of the material and showed an increase in bonding strength. These results suggest that atmospheric pressure plasma treatment of ceramic materials is an effective alternative to grit-blasting for adhesion enhancement.