On the potential of polyetheretherketone matrix composites reinforced with ternary nanolaminates for tribological and biomedical applications

We report the synthesis and characterization of PEEK-MAX (Ti3SiC2, Ti3AlC2, and Cr2AlC), and PEEK-MoAlB composites by hot-pressing. Detailed microstructure analysis by scanning electron microscopy showed that Ti3SiC2 particles are well dispersed in the PEEK matrix after the addition of 5 vol% Ti3SiC2 but at higher concentration (>= 10 vol%), the Ti3SiC2 particles segregated at the phase boundaries and formed interpenetrating micro-networks. PEEK-Ti3AlC2 and PEEK-MoAlB composites also showed similar structuring at the microstructural level. PEEK-Cr2AlC composites showed a different behavior where Cr2AlC particles were well dispersed in the PEEK matrix. All the three PEEK-MAX composites have lower hardness than PEEK-MoAlB composites as MoAlB particulates are appreciably harder than MAX phases but were harder than PEEK. Due to heterogenous nucleation, the addition of MAX phases or MoAlB reduced the crystallization temperature (T-c) by a few C-o. The formation of imperfect crystals also resulted in the lowering of melting point (T-m) of these composites. PEEK reinforced with 10 vol% Ti3SiC2, Ti3AlC2 and MoAlB showed plastic failure, and had higher strength than PEEK. Comparatively, PEEK reinforced with 10 vol% Cr2AlC did not show any enhancement. All the PEEK-MAX and PEEK-MoAlB composites showed triboactive behavior and enhanced wear resistance.