Mechanical properties of ion-implanted polycarbonate

The technique of ion implantation was employed for improving surface hardness and wear resistance of polycarbonate (PC). The samples of PC were implanted separately with C, Al, Ti, Fe and Ni ions to four doses of 2×1015 ions cm−2, 1×1016 ions cm−2, 5×1016 ions cm−2 or 1×1017 ions cm−2. Wear tests showed that the wear-resistance of PC was improved significantly and the friction coefficient was reduced after ion treatment, 2×1015 ions cm−2 C ion implantation produced the largest improvement in wear-resistance by a factor of 19 times and the friction coefficient was reduced by 20%. The nano-hardness increased from 0.283 GPa for the pristine PC to 0.712 GPa for 2×1015 ions cm−2 C-implanted PC and 1.032 GPa for 1×1016 ions cm−2 Ni-implanted PC. TRIM96 calculation revealed that ionization energy loss, vacancy energy loss and the difference in the energy loss for ionization and vacancies of Ni near the surface were more than those of the four other ions, and this was related to the largest improvement of surface hardness for Ni ion implantation. IR spectra of 2×1015 ions cm−2 C-implanted PC indicated that the surface of samples was moisture-retentive and formed a new carbonyl group.