The Aqueous Electrochemical Response of TiC–Stainless Steel Cermets

Abstract

A family of TiC-stainless steel ceramic-metal composites, or cermets, has been developed in the present study, using steel grades of 304 L, 316 L, or 410 L as the binder phase. Melt infiltration was used to prepare the cermets, with the steel binder contents varying between 10-30 vol. %. The corrosion behaviour was evaluated using a range of electrochemical techniques in an aqueous solution containing 3.5 wt. % NaCl. The test methods included potentiodynamic, cyclic, and potentiostatic polarisation. The corroded samples were subsequently characterised using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), while the post-corrosion solutions were analysed using inductively coupled plasma optical emission spectroscopy (ICP-OES) to determine the residual ionic and particulate material removed from the cermets during electrochemical testing. It was demonstrated that the corrosion resistance was enhanced through decreasing the steel binder content, which arises due to the preferential dissolution of the binder phase, while the TiC ceramic remains largely unaffected. Increasing corrosion resistance was observed in the sequence TiC-304 L > TiC-316 L > TiC-410 L.

Cermets and Hardmetals

“…Similarly, reducing the amount of Co binder increases the corrosion resistance [2], with selective leaching of Co noted in this study. In a similar vein, it was also shown for TiC-stainless steel cermets (grades 304L, 316L, and 410L) that corrosion resistance decreased with increasing steel binder content, while the steel composition also had a significant effect [5]; at the lowest binder contents (i.e., 10 vol.% steel), the corrosion resistance was comparable to the steel on its own, while the cermet had a roughly three-orders of magnitude lower wear rate. In comparing WC-WB-Co and WC-FeCrAl coatings, it was shown that the latter exhibited slightly improved corrosion resistance [3], although the two systems were broadly comparable.…”

“…The current special issue, with a focus on cermets and hardmetals, brings together seven scientific research papers [1][2][3][4][5][6][7] that investigate various aspects of these materials. The papers are broadly divided between WC-based hardmetal systems [1][2][3][4], lower density carbides including TiC [5] and NbC [6], and mixed oxide-carbide systems [7]. In two examples, the hardmetal is present as a thin coating on Cr-Ni-Mo based steel substrates [3,4].…”

“…In two examples, the hardmetal is present as a thin coating on Cr-Ni-Mo based steel substrates [3,4]. There is a strong emphasis among these articles on the evaluation of the material's corrosion behavior [2][3][4][5], highlighting the importance of corrosion resistance in a great many applications, along with their tribological responses [3,7], mechanical behavior [1,4,6,7], and the influence of grain size for near-nano variants [1,2].…”

Effect of Al Content on the Microstructure and Properties of As-Cast AlxCoCrCuFe Alloys

“…Besides that, the extension of the pseudo-passive region for the Al 0.9 CoCuCrFe alloy was almost the same (96 mV vs 100 mV for the Al 0.5 CoCuCrFe alloy). This region can be related to the formation of porous or poor protective oxide [ 24 ]. It is important to clarify that the corrosion tests were carried out just after the sanding of the surface of the sample; therefore, there was no time to form an appreciable oxide layer.…”