Microhardness of PEEK/ceramic micro- and nanocomposites: Correlation with Halpin–Tsai model

Microhardness of high performance PEEK matrix composites reinforced with micro- and nanosize ceramic particles of aluminum nitride and alumina was evaluated with Vickers hardness tester. The microhardness of composites increases with increasing ceramic particle loading. The microhardness of PEEK/AlN composites is higher than that of PEEK/Al2O3 composites. For a given volume fraction, the improvement in microhardness of nanocomposites is higher than that of microcomposites. For the first time, the Halpin–Tsai equation was applied to correlate the microhardness. It was found that the adjustable parameter, i.e. ξ, is different for both particles. The value of ξ is higher for nanocomposites compared to microcomposites.