A study on high performance poly(ether-ether-ketone) (PEEK) composites prepared by incorporating aluminum oxide (Al2O3), 0 to 50 wt % by hot compaction at 15 MPa and 350 degrees C was described. Density, thermogravimetric analysis/differential scanning calorimetry, and scanning electron microscopy (SEM) were employed to evaluate their density, thermal stability, crystallinity, and morphology. Experimental density was found higher than theoretical density, which indicates that composite samples are sound. It was found that the addition of micron sized (< 15 mu m) Al2O3 increased the peak crystallization temperature by 12 degrees C when compared with neat PEEK with insignificant increase in melting temperature. Half-time of crystallization is reduced from 2.05 min for the neat PEEK to 1.08 min for PEEK incorporated with 30 wt % Al2O3 because of the strong nucleation effect of Al2O3. The thermal stability of composites in air atmosphere was increased by 26 degrees C. However, thermal stability in nitrogen atmosphere decreases at lower concentration of Al2O3 but increases above 20 wt % of Al2O3. Uniform dispersion of Al2O3 particles was observed in PEEK polymer matrix by SEM. (c) 2006 Wiley Periodicals, Inc.