Characterization and fatigue damage of TiO2 layer on spark-anodized titanium before and after hot water treatment

► Water treatment of anodic TiO2 results in a nanostructured surface layer. ► Spark anodizing at 200 V has no significant influence on the fatigue life of titanium. ► Water-treated TiO2 layer shows severer fatigue damage than untreated one.