Room and High Temperature Tribological Performance of Multilayered TiSiN/TiN and TiSiN/TiN(Ag) Coatings Deposited by Sputtering

Filipe Fernandes,Diogo Cavaleiro,Abbas Al-Rjoub,Albano Cavaleiro,Tomas Polcar

doi:10.3390/coatings10121191

Filipe Fernandes, Diogo Cavaleiro + Show 3 more

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https://doi.org/10.3390/coatings10121191

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Abstract

In this study, we compare the tribological performance of a multilayer TiSiN/Ti(Ag)N coating with a TiSiN/TiN coating with a similar Si content in order to demonstrate the effect of the solid lubricant phase, silver. For Al2O3 balls, the hardness and reduced modulus determine the tribological performance of the coatings for tests conducted at room temperature (RT) against Al2O3 balls. At 550 °C, the TiSiN/TiN coating failed, whereas the Ag-containing coating performed better due to the presence of Ag in the contact, which decreased the shear stress and, consequently, the friction. For tests against TiAl6V4 balls, the Ag-containing coating was always better than the TiSiN/TiN one. At 550 °C, Ag in the wear track prevented the adhesion of the oxidized Ti-alloy wear debris in the contact, favoring the adhesion of wear debris from the coating to both the coating and counterpart surfaces. No wear could be measured for the 700 °C tests for both coatings due to different reasons: (i) the presence of oxidized adhered material from the ball to the reference TiSiN/TiN coating surface protected from wear and (ii) the presence of Ag-agglomerated particles decreased the friction and minimized the adhesion wear of the counterpart for the TiSiN/TiN(Ag) coating.

Highlights

The continuous growth in mobility has placed an increasing demand on the transport industry to manufacture vehicles at a lower cost, while ensuring that they operate efficiently, are friendly to the environment and meet safety requirements [1]
The wear mechanisms and wear debris were characterized by scanning electron microscopy (SEM)
An extensive discussion of the influence of Ag alloying on the structure and mechanical properties of multilayered TiSiN/TiN coatings can be seen in our previous publication [19]

Summary

Introduction

The continuous growth in mobility has placed an increasing demand on the transport industry to manufacture vehicles at a lower cost, while ensuring that they operate efficiently, are friendly to the environment and meet safety requirements [1]. This is important in the aerospace and automotive industries, where the use of lightweight airframes, as well as the global improvement of materials’ mechanical properties, encourage the integration of composite materials in a large number of structural components [1,2]. These include (i) the use of standard coolants and lubricants or cryogenic cooling, (ii) use of tools with a high thermal conductivity, (iii) optimization of the machining conditions

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