Tribological properties of ion-implanted polyphenylene oxide (PPO)

The technique of ion implantation was employed for improving surface hardness and wear resistance of polyphenylene oxide (PPO). The samples of PPO were implanted separately with Al, Ti and Fe ions to three doses of 2×1015, 1×1016 and 1×1017 ions/cm2. Wear tests showed that wear-resistance of PPO was improved significantly and friction coefficient was reduced. The 1×1016 ions/cm2 Ti ion implantation produced the largest improvement in tribological properties, and wear-resistance of 1×1016 ions/cm2 Ti-implanted PPO was improved over 270 times and friction coefficient was reduced by 40%. Nano-hardness increased from 0.369 GPa for the plain PPO to 1.433 GPa for 1×1016 ions/cm2 Ti-implanted PPO. TRIM96 (transport of ions in mater, version 1996) calculation revealed that ionization energy loss and energy loss difference between ionization and vacancies of Ti were more than those of Al and Fe beneath 50 nm ion implantation range, which were related to the largest improvement of surface properties for Ti ion implantation. IR-spectra of 1×1016 ions/cm2 Ti-implanted PPO indicated that the surface of samples was moisture-retentive and formed the carbonyl group. GXRD analysis showed that the crystal distance was reduced after Ti ion implantation.