AISI D3 tool steel was ion implanted with zirconium and the improvement in surface tribological properties investigated. The Zr ion implantation was done using a metal vapor vacuum arc broad-beam ion source, with a mean ion energy of 130 keV and at doses of 3.6 x 10(sup 16), 5 x 10(sup 16) and 1 x 10(sup 17) ions/cm2. Wear, friction and hardness of the implanted samples were measured and compared to the performance of unimplanted steel. The wear resistance was increased by about a factor of two, the friction remained about the same or was possibly increased by a small amount, and the hardness was improved by a factor of five or more by the ion implantation. We also investigated the effect on the Zr implantation profile of the multi-component energy distribution of the ion beam used here.