The effect of ion induced damage on the hardness, wear, and friction of zirconia

Abstract

Microhardness measurements were carried out on ion implanted single crystal Y2O3 stabilized cubic ZrO2. Inert gas ions (Ne, Ar, Xe) and N, Si, Ti, and W were implanted up to fluences of 3 × 1017 ions/cm2. Implantation energies were selected to give equivalent ranges. Comparison of the Knoop microhardness values of ZrO2 implanted with various species over a range of fluences showed that the principal variable causing hardness changes is damage energy and not the ion fluence nor the ion species. For all implants studied, the hardness versus damage energy gives a unified plot. At low doses the hardness rises with increasing deposited damage energy to a value 15% higher than that of unimplanted zirconia. With additional damage the hardness drops to a value 15% lower than that of the unimplanted zirconia. Friction and wear measurements in a pin-on-disk assembly showed very different behavior for high dose versus unimplanted ZrO2. The unimplanted samples showed debris with an associated rise in friction. The implanted system showed much less debris and a constant value of friction even after 10 000 cycles.