CORROSION PROPERTIES OF ANODIZED TITANIUM

Abstract

In this paper corrosion properties and microstructure features of amorphous self-organised TiO2 nanotubes electrochemically deposited on titanium are discussed. There was titanium of second grade used as a substrate for these experiments. There was a specific solution of ammonium fluoride, ethylenglycol and deionized water used to create an oxide layer with advantageous properties. Relation between changes of roughness indexes before and after anodization was found out. The wettability (contact angle) of artificial plasma on surface was measured using sessile drop method. It was found out that titanium dioxide nanotubes formed on the surface significantly decreases contact angle and time of anodization reduces it even more. Corrosion potentials, corrosion rate or polarization resistance were determined by linear polarization methods performed by ASTM standards. Corrosion potential of anodized samples is substantially more positive (≈ -50mV) compared with non-treated sample (≈ - 280mV). On the other hand polarization resistance was significantly higher for non-treated sample. Also potentials of passive layer breakdowns were found. Structure of nanotubes and influence of anodization on surface profile was studied by SEM.