Abstract:The surface morphology, corrosion resistance, fretting friction, wear properties and bioactivity of electrochemically polished surface on conventional Ti and ultrafine-grained Ti were investigated. The results show that compared to the electrochemically polished surface of conventional Ti, the electrochemically polished surface of ultrafine-grained titanium has more nano-scale corrosion pits, higher corrosion resistance (corrosion rate of the latter is 2/5 of the former) in the Kokubo simulated body fluid, lower friction coefficient (0.12 vs. 0.15), higher wear resistance (wear scar width of the latter is 4/5 of the former), and a slightly higher bioactivity (growth rate of Ca-P layer in simulated body fluid about 21.03 vs. 18.40 g/m2). It is believed that the above mentioned improvements were caused by the increase of crystal defects (internal energy) due to ultrafine microstructure.