LASER PROCESSING OF ORTHOPEDIC BIOMATERIALS - Advanced Biomaterials: Fundamentals, Processing, and Applications - page 308

(a)

200 μ m

(b)

20 μ m

Figure 9.26. Lower magnifi cation (a) and (b) higher magnifi cation secondary SEM images of
wear tracks on the surface of oxidized TNZT + 2B after friction studies using Si 3 N 4 counterface
balls. [Sonia Samuel et al. Wear Resistance of Laser Deposited Boride Reinforced Ti - Nb - Zr - Ta
Alloy Composites for Orthopedic Implants (to appear in Mater. Sci. Eng. C, 2007)]

titanium oxide layers, like the rutile phase have been shown to be very effective
in lowering the friction coeffi cients ( 0.2) and wear rates [45]. This narrowed the

wear tracks with no signifi cant third body debris formation that might result in
severe abrasive wear. Thus the titanium oxide layer acted as a lubricous oxide and
prevented boride particles from being potentially pulled out of the matrix,
and thereby improved the wear resistance considerably for both Ti-6Al-4V ELI
and TNZT + 2B. Lastly, there were no signifi cant differences in the wear track
morphologies between the alloys outside of some patchy regions in TNZT + 2B
that did not contribute to the overall friction behavior.

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