Improving the wear resistance of Al–Si alloy by ion implantation

Abstract

The mechanical properties of ion-implanted Al–Si alloy were studied using disk samples of alloy irradiated with Ar+, B+, and N2+ ions. Knoop hardness of ASTM 336.0 disks increased from 117 to 165 kgf/mm2 upon N2+ ion implantation. To measure tribological properties, lubricated ball-on-disk tests were performed using steel balls. The coefficients of friction of ion-implanted disks were higher than those of unimplanted ones. Ion implantation improved the wear resistance of the disks, and in the case of N2+ ion-implanted disks, the worn volume was smaller than 10−4 mm3. XPS analysis for the N2+ ion-implanted samples revealed the formation of aluminum and silicon nitride on the sample surface. On the other hand, the cross-sectional image of the ion-implanted surface showed precipitated Si which is held under the implanted N2+ ions.