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Anodic behaviour of WC‐Co type hardmetal
Author(s) -
Bozzini B.,
De Gaudenzi G. P.,
Fanigliulo A.,
Mele C.
Publication year - 2003
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.200390068
Subject(s) - dielectric spectroscopy , cyclic voltammetry , alloy , materials science , anode , scanning electron microscope , linear sweep voltammetry , tungsten carbide , energy dispersive x ray spectroscopy , electrochromism , carbide , spectroscopy , electrochemistry , phase (matter) , metallurgy , chemical engineering , analytical chemistry (journal) , composite material , chemistry , electrode , physics , organic chemistry , quantum mechanics , chromatography , engineering
An understanding of the anodic behaviour of WC‐Co type hardmetals is vital for the functional behaviour of this class of materials. The anodic oxidation of WC‐13Co grade hardmetal in 0.1 M H 2 SO 4 was investigated. This study is based on electrochemical (linear sweep voltammetry, cyclic voltammetry, impedance spectroscopy), compositional (energy dispersive spectroscopy), structural (X‐ray diffraction) and morphological (scanning electron microscopy) investigations. The potential range in which the oxidation of the Co‐alloy takes place with respect to the nobler carbide phase was defined. Within this potential interval a passivating behaviour for the binder alloy was shown. The potential threshold for WC oxidation was identified by monitoring the inception of the electrochromic loop. The anodic attack gives rise to the formation of hydrous WO 3 . The attack morphology is characterised by the alteration of the grain shape with formation of jelly‐like microscopic and flaky macroscopic structures.