Work

Formation of a Nanostructured Ti‐Si‐C‐N Coating by Self‐Organization with Reduced Amorphous Matrix

Year: 2024

Type: article

Abstract: A Ti-Si-C-N coating was deposited on AISI H11 hot working steel by plasma-enhanced chemical vapor deposition to investigate its micro- and nanostructure as well as its mechanical and thermal properties. Instead of a nanocomposite structure consisting of randomly oriented nanocrystalline grains < 10 nm surrounded by an amorphous matrix as usually found for these systems, this Ti-Si-C-N coating showed much larger TiC-grains with a preferred (200) orientation identified by X-ray diffraction analysis. The strong texturing und grain sizes > 10 nm of the coating were confirmed by high-resolution transmission electron microscopy images. The coating’s hardness was 46.3 GPa, making it equally hard to e.g. nanocomposite Ti-Si-N coatings. Despite 41.1 at.-% carbon content, amorphous carbon was not found, as evidenced by Raman spectroscopy analysis. In order to investigate the oxidation behavior of the coatings, X-ray diffraction was carried out at room temperature and in-situ in ambient atmosphere at elevated temperatures. The room temperature measurement showed a strong texturing of the TiC lattice and yielded additional information on an anisotropic grain size. At 950 °C, traces of rutile and anatase titanium dioxide can be identified in the X-ray diffraction pattern, marking this as the starting point for oxidation. After annealing, the TiC (200) Bragg reflection remains the dominant reflection, leading to the conclusion that a fully intact coating lies beneath a thin oxide layer.

Source: Advanced Materials Interfaces

DOI: 10.1002/admi.202400644