The effect of tribo-chemical reactions of mating materials on tribological behaviors of the B4C film in various relative humidity environments

Tribological Investigation of Boron Carbide Films Sliding Against Different Mating Materials Under High Relative Humidity

“…In the case of B 4 C bulk [14,23,24], it is found that the B 4 C bulk sliding against the WC ball achieves the minimum friction coefficient under the 50 % RH condition. In the case of B 4 C film [17], the B 4 C/WC friction pair also obtains the lowest friction coefficient and the wear rate under the 55 % RH condition. In the present investigation, the B 4 C/WC friction pair under 85 % RH with different normal loads achieves the lowest average friction coefficient and wear rate than those of the B 4 C/Al 2 O 3 and B 4 C/steel friction pairs.…”

“…In addition, a thin Cr interlayer about 200 nm was deposited on the top surface of the substrates to improve the adhesion. The specific deposition parameters and properties of the B 4 C film (shown in Table 1) were described in our previous article [17].…”

“…Friction and wear experiments of hot-pressed B 4 C sliding against 440C steel [14] and ZrO 2 [23] in the open air with 50 ± 5 % RH were studied by Erdemir et al and the friction coefficients are 0.6 ~ 0.7 and 0.3 ~ 0.4, respectively. In a previous work [17], we performed tribological tests on B 4 C films sliding against different mating materials and found that the tribological performances of the B 4 C/WC tribo-pair is much better than those of the B 4 C/Al 2 O 3 and B 4 C/steel tribo-pairs under 55 ~ 85 % RH conditions. High relative humidity (85 % RH) is one of common and important engineering application conditions, in which friction systems often operate at different normal loads and sliding speeds (or frequencies).…”

“…Based on this situation, several strategies have been adopted to reduce the friction coefficient, such as a pre-heat treatment [14], increasing the relative humidity (RH) [15][16][17] and adding additives [18][19][20][21]. Erdemir et al [14] reported that boron oxide (B 2 O 3 ) and boric acid (H 3 BO 3 ) were formed on the hot-pressed B 4 C surface after an annealing treatment, and hence the annealed B 4 C achieved a much lower friction coefficient (0.03 ~ 0.05).…”

“…High relative humidity (85 % RH) is one of common and important engineering application conditions, in which friction systems often operate at different normal loads and sliding speeds (or frequencies). However, previous friction tests [17] under 85 % RH only performed under a single normal load and speed (2 N and 5 Hz). And hence, it is necessary to further investigate the effect of the mating material on the tribological performances of the B 4 C film under a high relative humidity (85 % RH) with various normal loads and sliding frequencies.…”