ASPECTS CONCERNING THE WEAR AND CORROSION BEHAVIOR OF WC-COCR COATINGS AND RESPECTIVELY DLC/WC-COCR SYSTEMS

1,2 KAZAMER Norbert
Co-authors:
1,2 PASCAL Dragoș-Toader 2 MĂRGINEAN Gabriela 1 ȘERBAN Viorel-Aurel 2 BRANDL Waltraut 1,2 VĂLEAN Petru Cristian
Institutions:
1 Politehnica University Timișoara, Timișoara, Romania, EU, dragos.pascal@student.upt.ro
2 Westphalian University of Applied Sciences, Gelsenkirchen, Germany, EU
Conference:
8th International Conference on Nanomaterials - Research & Application, Hotel Voronez I, Brno, Czech Republic, EU, October 19th - 21st 2016
Proceedings:
Proceedings 8th International Conference on Nanomaterials - Research & Application
Pages:
383-388
ISBN:
978-80-87294-71-0
ISSN:
2694-930X
Published:
17th March 2017
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
23 views / 2 downloads
Abstract

Industrial branches are developing the best materials for their applications. An important part of surface engineering is represented by Physical Vapor Deposition (PVD) and Thermal Spraying techniques. The present work aims to investigate and compare the properties of multilayer coating systems obtained from PVD deposited Diamond-like Carbon (DLC) films on top of High Velocity Oxy-Fuel thermal sprayed WC-CoCr cermet interlayers to those of as-sprayed cermet coatings. In order to determine the coatings characteristics, the morphology, microstructure and chemical composition have been analyzed by means of Scanning Electron Microscopy combined with Energy-dispersive X-ray Spectroscopy (EDX). The EDX line-scan analysis confirms the existence of a gradient coating. The adhesion layer is a mixture of carbides, nitrides and carbonitrides. The presence of the cermet interlayer has several advantages like promoting adhesion to the metallic substrate and exhibiting a gradual distribution of the metal into ceramic, offering a better opportunity for the phase distribution of the top layer. Therefore, a further used method for the characterization of the cermet coating was X-ray diffraction. Several transformations in the phase content were observed and a decomposition of the ceramic phase was detected. The coefficient of friction, measured with a Pin-on-Disc Tribometer, stabilized quickly and remained constant for the WC-CoCr coating, whereas in the case of DLC/WC-CoCr it showed a lower steady state value with light fluctuations. Polarization measurements revealed a considerable dissolution of the metallic binder in the case of WC-CoCr coatings. Meanwhile, the DLC/WC-CoCr multilayer system performed significantly better under the same electrochemical testing conditions.

Keywords: DLC, WC-CoCr, HVOF, sputtering, multilayer coatings
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