Thermal evolution and mechanical properties of hard Ti-Cr-B-N and Ti-Al-Si-B-N coatings

Surface properties modification is an effective way to improve the performances of materials Subjected to thermo-mechanical stress. Nanocomposite Ti-B-N based coatings have high hardness, while their behavior at elevated temperatures can be enhanced through the addition of other elements. Mechanical properties and oxidation behavior of Ti-Cr-B-N and Ti-Al-Si-B-N coatings, deposited through ion implantation assisted magnetron sputtering on Si are presented. Microstructure investigation by XRD and TEM, hardness and Young's modulus by in plane and cross sectional nanoindentation, were performed on as-deposited coatings and after annealing in air at 900 degrees C. Evolution of morphology and microstructure and its relationship with coatings hardness is described. (C) 2008 Elsevier B.V. All rights reserved.