Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7881460 | Acta Materialia | 2014 | 11 Pages |
Abstract
Pulsed reactive magnetron sputtering was used to deposit Zr-B-C-N films as a function of the N2/Ar ratio in the plasma. The microstructure evolution of the films was studied by high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and nanoindentation. Zr-B-C-N films with a chemical composition (in at.% without 1-2 at.% H and < 1 at.% O and Ar) of Zr61B27C6N3, Zr41B30C8N20, Zr26B26C5N42 and Zr24B19C6N49 were produced using a nitrogen fraction of 0%, 5%, 10% and 15%. The Zr61B27C6N3 film consists of fcc B-rich Zr(B,C,N) nano-columnar structures concealed by an amorphous matrix. The fcc B-rich Zr(B,C,N) columns exhibit a preferred orientation with their [1 1 1] parallel to the film growth direction. The Zr41B30C8N20 film possesses the highest hardness and consists of nano-needle structures (â¼40 nm long and â¼10 nm wide) separated by amorphous boundaries. The nano-needles have a face-centered cubic (fcc) structure and are composed of ZrN and/or Zr(B,C,N) nano-domain structures (â¼2 nm) that are semi-coherently joined via Zr-N monolayer interfaces. The Zr26B26C5N42 film is composed mainly of refined crystalline ZrN nano-needle structures (â¼2 nm) embedded in an amorphous structure, and the Zr24B19C6N49 film has an amorphous-like structure. In the Zr41B30C8N20 film, the formation of ZrN and/or Zr(B,C,N) nano-domain structures, semi-coherently joined via Zr-N monolayer interfaces within the nano-needle structures, play a critical role in achieving high hardness and modulus. The annihilation of such a structure and the introduction of additional amorphous structure into the films by changing the N/Zr ratio via varying the N2 fraction in the gas mixture result in a significant decrease in the mechanical properties.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Minghui Zhang, Jiechao Jiang, JiÅà HouÅ¡ka, JiÅà Kohout, Jaroslav VlÄek, Efstathios I. Meletis,