Optical methods applied in thickness and topography testing of passive layers on implantable titanium alloys

The work presents the results of the applied surface pretreatment on topography and thickness of a passive layer of the anodically oxidized Ti6Al7Nb alloy. In our study were used: integrating sphere spectral measurements, bidirectional reflection distribution function (BRDF) method and optical profilometry. On the basis of the study, the passive layer thickness, roughness, waviness and the autocorrelation length were determined. The influence of voltage of anodization on topographical parameters of TiO2 has been discussed.