Abstract
Abstract Iso and non-iso architected TiN/Cr multilayers with constant composition were deposited by balanced magnetron sputtering aiming to investigate the influence of different architectures over coatings structures and properties. Glow discharge optical emission spectroscopy analyses were used to determine in-depth constituents and suggested that no diffusion of elements occurred between layers in room temperature. Field emission gun scanning electron microscopy analyses showed that all multilayers presented sharp interfaces and low porosity microstructures, with column-like grain growth influenced by layer sizes. Glancing angle X-ray diffraction analyses showed that multilayers consist of polycrystalline α-Cr and δ-TiN phases with a main peak in Cr(110) plane. The overlapping of TiN onto metallic layers led to the suppression of growth in the TiN(111) plane, although TiN layers thicker than 50 nm demonstrated a growth in plane TiN(200). Nanoindentation tests registered equal hardness values for all multilayers of around 16.2 GPa, on the other hand, a tendency to improve hardness has been identified for hierarchical multilayer. Oxidation tests revealed that architectures with thicker TiN top layers presented an improved oxidation resistance up to 600 oC, probably due to growth in more compact TiN(200) plane. However, TiN/Cr coatings did not resist integrally to oxidation tests at 750 oC.
Highlights
Thin films with high hardness are commonly applied to cutting tools, gears and bearings, aiming to protect against premature failure and enhance lifespan when facing everincreasing thermomechanical demands
Once the aim of this work is to evaluate the influence of architecture on titanium nitride (TiN)/ Cr multilayers, no bias nor external heating was applied for coating deposition, in order to limit the number of variables influencing the films
Energy-Dispersive X-ray Spectroscopy (EDS) analyses indicated that TiN/Cr multilayers are composed by similar Cr/Ti ratios, near to 1.2, revealing a regular composition of approximately 54.5 at.% Cr and 45.5 at.% TiN for all deposited coatings
Summary
Thin films with high hardness are commonly applied to cutting tools, gears and bearings, aiming to protect against premature failure and enhance lifespan when facing everincreasing thermomechanical demands. Despite the existence of individual layer coatings, those assembled with multilayers of different materials periodically distributed along the thickness tend to present improved wear, corrosion and oxidation resistances[1,2,3]. Such enhanced properties are mainly attributed to the presence of discontinuities among different layers, which significantly suppress cracks propagation and diffusion of chemical compounds along the internal structure. Multilayer thin films can reduce the excess of residual stress and restrict the columnar growth, which is common to ceramic coatings, favoring a stronger adhesion to substrates[4,5]. Multilayers are formed in an isostructural configuration with constant
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
