A new method for non-destructive stripping of coatings on titanium substrates

This work proposed a new method to prepare undamaged cross-sectional samples of coatings on titanium substrates. First, various kinds of coatings were fabricated on titanium substrates by electrochemical, chemical and physical methods. Then the coated samples were anodized in glycerol electrolyte containing NH4F (1 wt.%) + H2O (10 vol.%) at 50 V for 2 h, which resulted in coating detachment. Afterwards, coating cross-sectional samples were prepared with detached coating fragments and observed by scanning electron microscopy. The results showed that original internal microstructures of the coatings can be observed from the freshly-broken cross-sections, which might not be observed from samples prepared by existing methods. Finally, we concluded that it was the TiO2 nanotube layer formed between the coating and titanium substrate that caused the coating's detachment. The new method may be promising in detection, removing or transfer of coatings on titanium substrates.