Corrosion and erosion damage mechanisms during erosion–corrosion of WC–Co–Cr cermet coatings

Exposure effects of alkaline drilling fluid on the microscale abrasion–corrosion of WC-based hardmetals

“…Wear-corrosion performance of WC-based coatings have been extensively studied [19,[26][27][28][29][30][31][32]. The wear mechanism of WC coatings is considered to be similar to that of sintered hardmetals, with preferential removal of the binder phase leading to the undermining of the hard-phase [19].…”

“…The coatings are vulnerable since the binder-phase and the hard-phase are unevenly distributed within the coatings, however, increasing the content of the more corrosion resistant binder improves the wear and corrosion performance [27,31]. Souza and Neville [28,30] studied the corrosion characteristics of HVOF WC-10Co-4Cr in order to understand the effects of corrosion on the wear-corrosion behaviour of sprayed WC-based coatings. The electrochemical behaviour of UNS S31603 stainless steel was compared with a HVOF WC-10Co-4Cr coating and it was observed that unlike the continuous passive film of Cr 2 O 3 present on the stainless steel, only the CoCr matrix in the HVOF coating passivated and developed a thick Cr 2 O 3 film in a 3.5% NaCl solution.…”

“…Also, Takeda et al [33] observed a Cr 2 O 3 passive film on a WC-10Co-4Cr coating after immersion in Na 2 SO 4 solution and concluded that this film did not cover the entire surface and was present in the form of islands. Discontinuity in the film is likely to coincide with the binder-carbide interface and hence corrosion is likely to be initiated at this interface when corrosive electrolytes are present [30].…”

“…Attempts have been made to calculate the value of PC using in situ electrochemical measurements during erosion-corrosion [28,30] and during abrasion-corrosion by modifying a microabrasion tester [35,36]. In the present work, the pure corrosion (PC) parameter was evaluated from the corrosion rate (CR) obtained from potentiodynamic polarisation curves and converted to a specific wear rate (κ corr ).…”

Corrosion Behavior of WC-Co Cermet Coatings

“…Cermets consist of ceramic particulate embedded in a metallic binder [1][2][3][4][5]. The reinforcing particles help the composite to perform better than alloys.…”