Lubricating mechanisms of sulfurized olefin on oxynitrided steel surface under boundary lubrication condition

In this paper, Al7075 alloy and 15 wt% VN/7075 composite were prepared by ball milling and hot-press sintering. The microstructure, hardness, and wear behavior under different working conditions (environmental condition: dry friction, sulfur-containing boundary lubrication, and oil lubrication) were studied. The results showed that the distribution of VN was dispersive and uniform in 15 wt% VN/7075 composite without obvious agglomeration. The hardness (119.5 Hv) of 15 wt% VN/7075 composite was 46.1% higher than the Al7075 alloy (81.8 Hv). Friction and wear behavior test results showed that under sulfur-containing boundary lubrication condition, according to the tribofilm layer on the worn surface of 15 wt% VN/7075 composite, the friction coefficient of 15 wt% VN/7075 composite decreased by 37.6% compared with the Al7075 alloy. The main wear mechanism of 15 wt% VN/7075 composite was delamination wear and abrasive wear under dry friction, while under sulfur-containing boundary lubrication and oil lubrication, it changed to mild abrasive wear.

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A scuffing model considering additive depletion in boundary lubrication

Industrial Lubrication and Tribology ◽

10.1108/ilt-05-2019-0183 ◽

2019 ◽

Vol 72 (3) ◽

pp. 267-272

Author(s):

Bora Lee ◽

Yonghun Yu ◽

Yong-Joo Cho

Keyword(s):

Boundary Lubrication ◽

Mass Conservation ◽

Additive Concentration ◽

Contact Conditions ◽

Sliding Bearings ◽

Content Type ◽

Proposed Model ◽

Lubrication Condition ◽

Scuffing Failure ◽

Sliding Distance

Purpose This paper aims to propose a new scuffing model caused by the depletion of additives in boundary lubrication condition. Design/methodology/approach The differential equation governing the distribution of additive content in the fluid film was used. This formula was derived from the principle of mass conservation of additives considering the consumption due to surface adsorption of wear particles. The occurrence of scuffing was determined by comparing the wear rate of the oxide layer with the oxidation rate. Findings If the additive becomes depleted while sliding, the scuffing failure occurs even at a low-temperature condition below the critical temperature. The critical sliding distance at which scuffing failure occurred was suggested. The experimental data of the existing literature and the theoretical prediction using the proposed model are shown to be in good agreement. Originality/value It is expected to be used in the design of oil supply grooves for sliding bearings operating under extreme conditions or in selecting the minimum initial additive concentration required to avoid scuffing failure under given contact conditions.

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Effect of Mo on tribological behaviors of atmospheric plasma sprayed Al2O3-13%TiO2/Mo coatings under boundary lubrication condition

Ceramics International ◽

10.1016/j.ceramint.2020.03.041 ◽

2020 ◽

Vol 46 (10) ◽

pp. 15066-15075

Author(s):

Chao Zhang ◽

Bo Huang ◽

Jinyong Xu ◽

Wenjian Cao ◽

Guodong Sun ◽

...

Keyword(s):

Boundary Lubrication ◽

Atmospheric Plasma ◽

Tribological Behaviors ◽

Lubrication Condition ◽

Plasma Sprayed

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On the effort to discriminate the principal function of tribofilm on friction under the boundary lubrication condition

Tribology International ◽

10.1016/j.triboint.2010.02.001 ◽

2011 ◽

Vol 44 (6) ◽

pp. 702-710 ◽

Cited By ~ 6

Author(s):

Masabumi Masuko ◽

Mikiya Shibatsuji ◽

Masato Yokomizo ◽

Saiko Aoki ◽

Akihito Suzuki

Keyword(s):

Boundary Lubrication ◽

Principal Function ◽

Lubrication Condition

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TRIBOLOGICAL CHARACTERISTICS OF RADIAL JOURNAL BEARINGS BY ULTRASONIC NANOCRYSTAL SURFACE MODIFICATION TECHNOLOGY

International Journal of Modern Physics B ◽

10.1142/s0217979210066008 ◽

2010 ◽

Vol 24 (15n16) ◽

pp. 3011-3016 ◽

Cited By ~ 11

Author(s):

YOUNG SHIK PYOUN ◽

JEONG HYUN PARK ◽

CHANG MIN SUH ◽

INHO CHO ◽

CHANG-SOON LEE ◽

...

Keyword(s):

Surface Modification ◽

Boundary Lubrication ◽

Transition Period ◽

Hydrodynamic Lubrication ◽

Peak Torque ◽

Bearing Steel ◽

Journal Bearings ◽

Mixed Lubrication ◽

Stribeck Curve ◽

Lubrication Condition

Ultrasonic nanocrystal surface modification (UNSM) has applied to a radial journal bearings made of bearing steel SUJ2. Mechanical characteristics are compared between UNSM treated and untreated bearings. Friction torque is measured at the boundary lubrication condition, the mixed lubrication condition, and the full hydrodynamic lubrication condition. The peak torque at the boundary lubrication condition and the transition period to mixed lubrication condition on the UNSM treated samples are reduced. These effects are very useful to improve the service life of journal bearings. The Stribeck curve at the mixed and full hydrodynamic lubrication is derived and compared. The friction coefficient at these two regimes is reduced by more than 50%, which will do effective role for improvement of energy efficiency. The major effects for this reduction at three lubrication regimes could be explained in the terms of micro dimple surface.

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