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Surface and Coatings Technology, Volume 215, 25 January 2013, Pages 186-191.
J. VlCek, P. Steidl, J. Kohout, R. Cerstvý, P. Zeman, Š. Proksová, V. Perina.
Department of Physics, University of West Bohemia, Univerzitní 22, 306 14 Plzeň, Czech Republic and
Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Řež near Prague, Czech Republic.
Abstract.
Zr–B–C–N films were deposited on silicon and glass substrates using pulsed magnetron co-sputtering of a single B4C–Zr target (at 15% or 45% of zirconium in the target erosion area) in nitrogen–argon gas mixtures. A planar unbalanced magnetron was driven by a pulsed dc power supply operating at a repetition frequency of 10 kHz with a fixed 85% duty cycle. The total pressure was 0.5 Pa and the substrate temperature was adjusted to 450 °C during the depositions on the substrates at a floating potential. High-quality defect-free films, 3.5 to 4.1 um thick, with smooth surfaces (the average roughness Ra ≤ 4 nm) and good adhesion to substrates at low compressive stresses (less than 0.9 GPa) were produced. Hard (37 GPa) nanocolumnar ZrB2-type films of the Zr25B57C14N3 composition (in at.% without 1 at.% of hydrogen) with a very low compressive stress (0.4 GPa), high electrical conductivity (electrical resistivity of 2.3 × 10− 6 Ωm) and high oxidation resistance in air up to 650 °C were prepared in pure argon at a 15% Zr fraction in the target erosion area. Hard (37 GPa) nanocomposite Zr41B30C8N20 films with a low compressive stress (0.6 GPa), even higher electrical conductivity (electrical resistivity of 1.7 × 10− 6 Ωm) and high oxidation resistance in air up to 550 °C were deposited in a 5% N2 + 95% Ar gas mixture at a 45% Zr fraction in the target erosion area. Increasing the N2 fraction (> 5%) in the gas mixture resulted in a significant decrease of the film hardness and in a rapid rise in their electrical resistivity and oxidation resistance in air at elevated temperatures due to a growing volume fraction of an amorphous phase with a high content of nitrogen (up to 52 at.%) in the materials.
