Oxidation kinetics of overstoichiometric TiB2 thin films grown by DC magnetron sputtering. (September 2022)

• Record Type: Journal Article
• Authors: Dorri, Samira; Palisaitis, Justinas; Greczynski, Grzegorz; Petrov, Ivan; Birch, Jens; Hultman, Lars; Bakhit, Babak
• Is Part Of: Corrosion science. Volume 206(2022)
• Publication Date: 2022-09
• Subjects: Sputtering -- Thin films -- Titanium diboride (TiB2) -- Microstructure -- Oxidation; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110493
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: We systematically study the oxidation properties of sputter-deposited TiB2.5 coatings up to 700 °C. Oxide-scale thickness dox increases linearly with time ta for 300, 400, 500, and 700 °C, while an oxidation-protective behavior occurs with d ox = 250 ∙ t a 0.2 at 600 °C. Oxide-layer's structure changes from amorphous to rutile/anatase-TiO2 at temperatures ≥ 500 °C. Abnormally low oxidation rate at 600 °C is attributed to a highly dense columnar TiO2 -sublayer growing near oxide/film interface with a top-amorphous thin layer, suppressing oxygen diffusion. A model is proposed to explain the oxide-scale evolution at 600 °C. Decreasing heating rate to 1.0 °C/min plays a noticeable role in the TiB2.5 oxidation. Graphical Abstract: ga1 Highlights: Oxidation properties of sputter-deposited TiB2.5 coatings are studied up to 700 °C. TiB2.5 shows counterintuitive oxidation behavior at 500 and 600 °C. Oxide-scale thickness dox increases linearly with time for 300, 400, 500, 700 °C. At 600 °C, an oxidation-protective behavior takes place with d ox = 250 ∙ t a 0.2 . Abnormally low oxidation rate at 600 °C is due to a highly dense columnar TiO2 .