TEM Investigations of (Ti, Si)N Layer Coated on Magnesium Alloy Using PVD Technique

摘要

Thin films and coatings are applied to structural bulk materials in order to improve properties of the surface, such as wear resistance, corrosion resistance, as well as hardness. The research issue, presented in this paper, concerning the production of coatings is one of the most important directions of surface engineering, ensuring the obtainment of coatings of high usable properties in the scope of mechanical characteristics and wear resistance. The general purpose of this work is to confirm the quality and make an evaluation the obtained Ti/(Ti,Si)N/(Ti,Si)N coating - which is a multilayer coating, consisting of a Ti layer, a (Ti,Si)N layer, as well as a (Ti,Si)N layer on magnesium cast alloy substrate. While investigating the coating material, there were studied the transition zone between the coating and the substrate material as well the occurrence of some structure defects which can be present after the deposition process and could have any influence of the properties of the achieved coating. The droplets observed in SEM are noticeably different in terms of size and shape (regular and irregular shape, slightly flat). There were also some hollows formed probably when the solidified droplets break off after the used process has been. The obtained coatings reveal a compact structure, without visible delamination and defects, they are uniform and tightly adhere to each other as well to the substrate. In the present work, the goal is set on nanocomposite thin films and coatings deposited by physical vapour deposition (PVD) technique. This investigation will touch some aspects of such coatings, but the main objective is to give a general view on features revealed using electron microscopy application in PVD coating investigations.