Figure 12.
Tribological properties of the PAA-modified Ti6Al4V under different loads and at different velocities: (a1) the average friction coefficients under different loads; (a2) the friction coefficients versus time under different loads; (a3) wear morphologies of the PAA-modified Ti6Al4V and the PTFE ball under the load of 40 N; (b1) the average friction coefficients under different velocities; (b2) the friction coefficients versus time under different velocities; (b3) wear morphologies of the PAA-modified Ti6Al4V and the PTFE ball at the velocity of 24 mm/s.