Influence of Ta on the oxidation resistance of WB2−z coatings

Fuger C, Schwartz B, Wojcik T, Moraes V, Weiss M, Limbeck A, Macauley C, Hunold O, Polcik P, Primetzhofer D, Felfer P, Mayrhofer PH, Riedl H (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Journal of Alloys and Compounds Elsevier

Article Number: 158121

DOI: 10.1016/j.jallcom.2020.158121

Abstract

Ternary W1−xTaxB2−z is a promising protective coating material possessing enhanced ductile character and phase stability compared to closely related binaries. Here, the oxidation resistance of W1−xTaxB2−z thin films was experimentally investigated at temperatures up to 700 °C. Ta alloying in sputter deposited WB2−z coatings led to decelerated oxide scale growth and a changed growth mode from paralinear to a more linear (but retarded) behavior with increasing Ta content. The corresponding rate constants decrease from kp* = 6.3 ⋅ 10−4 µm2/s for WB2−z, to kp* = 1.1 ⋅ 10−4 µm2/s for W0.66Ta0.34B2−z as well as kl = 2.6 ⋅ 10−5 µm/s for TaB2−z, underlined by decreasing scale thicknesses ranging from 1170 nm (WB2−z), over 610 nm (W0.66Ta0.34B2−z) to 320 nm (TaB2−z) after 10 min at 700 °C. Dense and adherent scales exhibit an increased tantalum content (columnar oxides), which suppresses the volatile character of tungsten-rich as well as boron oxides, hence being a key-factor for enhanced oxidation resistance. Thus, adding Ta (in the range of x = 0.2–0.3) to α-structured WB2−z does not only positively influence the ductile character and thermal stability but also drastically increases the oxidation resistance.

Authors with CRIS profile

Chandra Macauley Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften) Peter Felfer Professur für Atom Probe Tomography

Additional Organisation(s)

Lehrstuhl für Werkstoffwissenschaften (Allgemeine Werkstoffeigenschaften)

Related research project(s)

In-situ nanomechanics and FIB tomography of thin films (EXC315 EAM (A2-3)) Exzellenz-Cluster Engineering of Advanced Materials Nov. 1, 2012 - Oct. 31, 2017

Involved external institutions

Technische Universität Wien / Vienna University of Technology AT Austria (AT) Plansee Composite Materials GmbH DE Germany (DE) Oerlikon Balzers Coating Germany GmbH DE Germany (DE) Uppsala University SE Sweden (SE)

How to cite

APA:

Fuger, C., Schwartz, B., Wojcik, T., Moraes, V., Weiss, M., Limbeck, A.,... Riedl, H. (2020). Influence of Ta on the oxidation resistance of WB2−z coatings. Journal of Alloys and Compounds. https://doi.org/10.1016/j.jallcom.2020.158121

MLA:

Fuger, C., et al. "Influence of Ta on the oxidation resistance of WB2−z coatings." Journal of Alloys and Compounds (2020).

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