Tribochemistry in sliding wear of TiCN–Ni-based cermets

Abstract

The tailoring of cermet composition to improve tribological properties requires careful choice of the type of secondary carbide. To investigate this aspect, a number of sliding tests were carried out on baseline TiCN-20Ni cermet and TiCN-20wt%Ni-10 wt% XC cermets (X ‫ס‬ W/Nb/Ta/Hf) at varying loads of 5N, 20N, and 50N against bearing steel. With these experiments, we attempted to answer some of the pertinent issues: (i) how does the type of secondary carbide (WC/NbC/TaC/HfC) influence friction and wear behavior, and is such influence dependent on load?; and (ii) how does the secondary carbide addition affect the stability and composition of the tribochemical layer under the selected sliding conditions? Our experimental results reveal that the added secondary carbides influence chemical interactions between different oxides and such interactions dominate the friction and wear behavior. A higher coefficient of friction (COF) range, varying from 0.75 to 0.64 was recorded at 5N; whereas the reduced COF of 0.46-0.52 was observed at 20N or 50N. The volumetric wear rate decreased with load and varied on the order of 10 −6 to 10 −7 mm 3 /Nm for the cermets investigated. The cermet containing HfC exhibited high friction and poor wear resistance. At low load (5N), the abrasion and adhesion of hard debris containing various oxides dominated the wear, and resulted in high friction and wear loss. In contrast, the more pronounced increase in friction-induced contact temperature (below 500°C) and compaction of hard debris resulted in the formation of a distinct tribochemical layer at higher loads (20N and 50N). The formation of a dense tribolayer containing oxides of iron and/or titanium is responsible for the reduced friction and wear, irrespective of secondary carbides.

Friction and Wear Properties of WC/C Nano-Scale Multilayer Coatings on Technical Surfaces

“…This originates from the ball surface. The significantly lower quantity of carbon measured in the transfer layer in comparison with the unworn coating could be the result of a tribochemical reaction when WC from the WC/C multilayer coating is oxidized by atmospheric oxygen resulting in the formation of oxides such as WO 3 and CO [17]. Singer et al [15] examined the friction and the contact zone in situ between a diamond-like nanocomposite coating and sapphire lens using an tribometer.…”

Abrasion wear, thermal shock and impact resistance of WC-cemented carbides produced by PECS and LPS

“…The 5M-7Ni samples gave the highest 100Cr6 steel ball wear rates (Fig. 8), due to significantly higher hardness than the steel balls (hardness~7 GPa [38]). The wear rate of the 100Cr6 balls increased with sample hardness, and there was an iron oxide debris (tribolayer) on the wear tracks of the 5N-s and 5M-7Ni-u samples (Fig.…”

“…9), the latter having more of the tribolayer [39]. The coefficient of friction, μ, with the 100Cr6 steel balls reduced with increased sample hardness (Table 6), because the iron oxide tribolayer acted as a lubricant [38]. The 5N-s and 5M-7Ni-u samples had higher hardness than the Si 3 Ni 4 balls, so acted as abrasive bodies, wearing the balls [39].…”

Microstructure–Mechanical Properties–Wear Resistance Relationship of SiAlON Ceramics

“…It can be further noted that this model has been used in our earlier research work. [7,25,26] According to Archard, the contact temperature depends on the thermal conductivity, COF, contact stress, and sliding speed. The contact-temperature rise (DT m ) can be calculated using the following formula:…”