Abstract
The wear and friction properties of poly (etherโetherโketone) (PEEK) reinforced with 0โ33 vol % (60 wt %) micron size Al~2~O~3~ composites were evaluated at a sliding speed of 1.0 m/s and nominal pressure from 0.5 to 1.25 MPa under dry sliding conditions using a pinโonโdisk wear tester. The wear resistance of the pure PEEK is 10โfold higher than that of mild steel under the similar test condition. It is improved to 18โfold as compared with mild steel at 3.5 vol % Al~2~O~3~ content. The improvement in wear properties may be attributed to the thin, tenacious, and coherent transfer film formed between the steel countersurface and composite pin. However, the wear resistance of PEEK containing above 3.5 vol % Al~2~O~3~ was deteriorated, despite their higher hardness and stiffness as compared with that of composites containing lower Al~2~O~3~ content. This is attributed to the formation of thick and noncoherent transfer film, which does not prevent the wear of the composites from hard asperities of countersurface. Moreover, hard Al~2~O~3~ particles present in transfer film act as third body wear mechanism. The coefficient of friction of the composites is higher than that of pure PEEK. SEM and optical microscopy have shown that wear of pure PEEK occurs by the mechanism of adhesion mainly whereas of PEEK composites by microploughing and abrasion. ยฉ 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008