High temperature tribological behaviour of borided surfaces based on the phase structure of the boride layer

Evaluation of the effect of boride layer structure on the high temperature wear behavior of borided steels

“…By following the methodology presented in Ref. 16 (as also described in the Appendix), thermal stress developed in boride layers of 31CrMoV9 and X40CrMoV5-1 steels were calculated as þ375 MPa (tensile) and À 505 MPa (compressive), respectively. Since tensile type thermal stress encourages crack initiation and propagation [6], it accelerated material removal from the contact region of the borided 31CrMoV9 steel by crack induced spalling as reflected in the friction curve by heavy fluctuations (Fig.…”

“…When thermochemical diffusion processes are of concern, boriding results in the formation of single (Fe 2 B) or dual-phase (Fe 2 BþFeB) surface layers on ferrous alloys depending on the process parameters [14,15]. In a recent study, tribological performances of singlephase (consisting of 35 μm thick Fe 2 B layer) and dual-phase (consisting of 118 mm thick Fe 2 B and 52 μm thick FeB layers) boride layers formed on 4140 quality steel have been examined at room and elevated temperatures [16]. Although similar tribological behavior was observed at RT, dual-phase boride layer exhibited superior wear resistance to single-phase boride layer especially at 500 1C.…”

“…Being motivated by the results of Ref. 16, this study was initiated with the aim to determine the impact of V FeB on high temperature wear resistance of dual-phase boride layers. More specifically, boride layers formed on two different steels with identical total thicknesses were subjected to wear tests at RT and 500 1C.…”

Effect of heat treatment temperature on the structure and tribological properties of nanometer lanthanum borate

“…The structural instability of the hydrogen bonds under high temperatures causes the breaking of chemical bonds, the removal of hydroxyl radicals, and the release of a large amount of crystal water and reactive oxygen. The resulting expansion of the specific surface area and increase in chemical activity of the nanometer lanthanum borate [17][18][19], on the one hand, activate the catalytic performance of the rare-earth element La, resulting in the boronization between the B and Fe base [11], the formation of FeB film (lowbinding energy), and the effective reduction in contact force and abrasive wear [20]. On the other hand, they help with the formation of an La2O3 oxidation film between La and reactive oxygen, which compensates for the surface wear and thus reduces friction and wear.…”

Sliding Wear Behavior of Friction Couples Primarily Selected for Corrosion Resistance: Iron Boride/Iron Boride and Iron Boride/Yttria-Stabilized Zirconia

“…An alternative to solely "boride" both surfaces is to select another rather inert counter-body than iron borides. Data already exist for the couple borided steel/alumina [36,37]. In friction tests, friction coefficient starts from 0.15-0.2, but increases due to the formation of superficial oxides, to reach the same value as untreated steel (0.5-0.7) [36].…”