LAUSR

Abstract Tb 3+ doped ZrO 2 coatings were formed on zirconium substrate by plasma electrolytic oxidation (PEO) in electrolyte containing Tb 4 O 7 powder. The evolution morphology, chemical composition, and crystalline structure of formed coatings as a function of PEO time are probed by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The concentration of Tb incorporated into coatings increases with the time of PEO processing. Obtained coatings are crystallized and composed of monoclinic and tetragonal phases of ZrO 2 . The ratio of monoclinic and tetragonal phases, as well as crystallite size, is controlled by PEO time and concentration of Tb in coatings. Photoluminescence (PL) emission spectra of Tb doped ZrO 2 coatings feature two distinct regions. The first region is related to ZrO 2 PL band with a maximum positioned at about 490 nm, while the second region features several sharp emission bands which can be attributed to f-f transitions of Tb 3+ from excited level 5 D 4 to lower levels 7 F J ( J = 2,3,4,5, and 6). PL excitation spectra of Tb doped ZrO 2 coatings are characterized by broad band region from 250 nm to 350 nm with a maximum at around 280 nm originating from 4f 8 → 4f 7 5d 1 transition of Tb 3+ ions. The evolution of PL emission spectra shows that with increasing PEO time, i.e. increasing concentration of Tb in coatings, sharp emission bands of Tb 3+ increase, while PL intensity of broad emission band of ZrO 2 host decreases. These results indicate the existence of energy transfer from ZrO 2 host to Tb 3+ dopant.