Influence of the microstructure on corrosion induced damage of WC-Co cemented carbides

ABSTRACT

The main goal of the present work is to study the influence of the microstructure on the corrosion behavior of cemented carbides WC-Co in two corrosive media. Corrosion kinetics were determined by immersion tests while the electrochemical evolution of the Surface was analyzed using impedance testing. Damage tolerance to corrosion was evaluated by assessing fracture strength on specimens previously subjected to corrosion. Results pointed out that for both grades the corrosion rate was higher in seawater, being more significant for the grade with a medium grain size. The corrosion phenomenon that took place in both media was caused by the oxidation reaction of cobalt. In seawater, the polarization resistance decreased for both grades whereas in mine water increased, due to the formation of a layer of corrosion products, which slowed down the cobalt dissolution process in Surface. In both media, a greater strength loss of the ultrafine grades was evidenced.

KEYWORDS:

• Cemented carbides
• corrosion kinetics
• sea water
• mine water

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes on contributors

Dr. G. Fargas is an associate professor in the Department of Materials Science and Engineering at UPC. Her research activity focuses on the correlation between microstructure and mechanical properties, corrosion and wear resistance of advanced stainless steels, zirconia-based ceramics, and inorganic matrix composites. Since September 2017, she has been the UPC coordinator of the European project Additive Manufacturing Initiative for Transnational Innovation in Europe (AMITIE). From 2015 to 2017, she was assistant director of Research, Enterprise, Knowledge Transfer and Mobility at the Barcelona College of Industrial Engineering (EUETIB). From 2017 to February 2019, Dr. Fargas was assistant director of Mobility, Enterprise and Promotion at the EEBE. From February 2019, she is the vice-rector for social responsibility and equality at UPC.

Dr. C. M. Müller is full professor in the Department of Materials Science and Physical Chemistry in the University of Barcelona (Spain) and member of the European Board of the European Academy of surface Technology (EAST). He is Director of the Electrodeposition and corrosion (ELECTRODEP) group at UB. His research interests include applied electrochemistry, surface technology and corrosion. Dr. Muller is an active member of the International Society of Electrochemistry (ISE), co-author of more than 100 papers published in top journals in these fields, and has been Co-Chairman of several International Conferences and courses.

Dr. D. Sosa received his PhD degree in 2010 from National University of Mar del Plata (UNMDP). He is assistant professor and Head of department of Mechanical Engineering in the UNMDP, as well as assistant researcher of National Scientific and Technical Research Council (CONICET) in Argentina. He is director of the Mechanical technology research group of UNMDP and staff member of Metallurgy division of Research Institute of Materials Science and Technology (INTEMA). His research interests include materials and manufacturing technology. Dr. Sosa is co-author several research papers and has presented lectures in many International Congress on materials Science and Engineering. He is member of the Argentine Association of Materials.

Dr. J. Tarragó has received a Ph.D. degree in Materials Science and Engineering from the Technical University of Catalonia - BarcelonaTech (UPC, Spain). After his Ph.D., he worked as an R&D engineer and project manager for Sandvik Mining and Rock Technology and Hyperion Materials & Technologies, respectively. His field of expertise is in cemented carbides, particularly in new material development and mechanical properties assessment. Now he is enrolled in a Full-time MBA at Mannheim Business School, Germany.

Dr. E. Tarrés is the Technology Manager - Carbide Products for Hyperion Materials & Tecnologies. Elena joined the company in April 2008 in Coventry, U.K., as an R&D Engineer becoming Technology Manager in September 2012. Since then, she has held different responsibilities within the department such us leading collaborations with Universities and third parties, the Metal Cutting and Process Lines teams and carbide New Product Development. In 2016-17, she actively participated in the relocation project of both the R&D carbide team and lab from Coventry to Barcelona, Spain; project that implied her own relocation. From 2017 onwards, Elena has been responsible for establishing and consolidating the Hyperion's carbide R&D team in Barcelona. Elena has got a Bachelor's degree in Chemistry by the Universitat de Barcelona and spent 4 years, until April 2008, as a PhD student in CIEFMA group of the Universitat Politècnica de Catalunya. During her PhD years, Elena worked on characterising and understanding the tribomechanical behaviour of ceramic-coated cemented carbides systems.

Dr. J. Fair received a PhD degree in materials science - organic photoconductors at University of Dundee (UK) in 1999. As Manager of Materials & Process Competence at Sandvik Hyperion, he was responsible for identifying, exploring and developing new material concepts, improved manufacturing platforms and material modelling capabilities. His research resulted in a range of publications as well as a number of patents in the field of hard materials. He is currently Senior Project Manager (Material Technology) at Mahle Engine Systems UK Ltd.

Dr. L. Llanes is full professor in the Department of Materials Science and Engineering as well as board member of the Barcelona Research Center in Multiscale Science and Engineering, in the Technical University of Catalonia - BarcelonaTech (UPC, Spain). He received his PhD degree in 1992 from the University of Pennsylvania (USA). He is Director of the Structural Integrity, Micromechanics and Reliability of Engineering Materials (CIEFMA) group at UPC. His research interests include mechanical integrity and damage assessment of