Multifunctional porous titanium oxide coating with apatite forming ability and photocatalytic activity on a titaniumsubstrate formed by plasma electrolytic oxidation
Plasma electrolytic oxidation (PEO)was used tomake a multifunctional porous titaniumoxide (TiO2) coating on
a titanium substrate. The key finding of this study is that a highly crystalline TiO2 coating can be made by
performing the PEO in anammoniumacetate (CH3COONH4) solution; the PEO coatingwas formed by alternating
between rapid heating by spark discharges and quenching in the solution. The high crystallinity of the TiO2 led to
the surface having multiple functions, including apatite forming ability and photocatalytic activity. Hydroxyapatite
formed on the PEO coating when it was soaked in simulated body fluid. The good apatite forming ability can
be attributed to the high density of hydroxyl groups on the anatase and rutile phases in the coating. The degradation
of methylene blue under ultraviolet radiation indicated that the coating had high photocatalytic activity.