Study on the selectivity of calcium carbonate nanoparticles under the boundary lubrication condition

Wear ◽  
2013 ◽  
Vol 307 (1-2) ◽  
pp. 35-43 ◽  
Author(s):  
Nan Xu ◽  
Ming Zhang ◽  
Weimin Li ◽  
Gaiqing Zhao ◽  
Xiaobo Wang ◽  
...  
Author(s):  
Yaping Bai ◽  
Mengmeng Liu ◽  
Jianping Li ◽  
Yongchun Guo

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.


2019 ◽  
Vol 72 (3) ◽  
pp. 267-272
Author(s):  
Bora Lee ◽  
Yonghun Yu ◽  
Yong-Joo Cho

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.


2020 ◽  
Vol 46 (10) ◽  
pp. 15066-15075
Author(s):  
Chao Zhang ◽  
Bo Huang ◽  
Jinyong Xu ◽  
Wenjian Cao ◽  
Guodong Sun ◽  
...  

2011 ◽  
Vol 44 (6) ◽  
pp. 702-710 ◽  
Author(s):  
Masabumi Masuko ◽  
Mikiya Shibatsuji ◽  
Masato Yokomizo ◽  
Saiko Aoki ◽  
Akihito Suzuki

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3011-3016 ◽  
Author(s):  
YOUNG SHIK PYOUN ◽  
JEONG HYUN PARK ◽  
CHANG MIN SUH ◽  
INHO CHO ◽  
CHANG-SOON LEE ◽  
...  

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.


2013 ◽  
Vol 65 ◽  
pp. 265-269 ◽  
Author(s):  
Nor Azmmi Bin Masripan ◽  
Kenji Ohara ◽  
Noritsugu Umehara ◽  
Hiroyuki Kousaka ◽  
Takayuki Tokoroyama ◽  
...  

2015 ◽  
Vol 67 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Gabi N Nehme ◽  
Saeed Ghalambor

Purpose – This paper aims to focus on the topics of phosphorus (P) and sulfur (S) in engine oil. Very reproducible boundary lubrication tests were conducted as part of Design of Experiments software to study the behavior of fluorinated catalyst iron fluoride (FeF3) and polytetrafluoroethylene (PTFE) in the development of environment-friendly (reduced P and S) anti-wear additives for future engine oil formulations. Multi-component fully formulated oils were used with and without the addition of PTFE and fluorinated catalyst to characterize and analyze their performance. Design/methodology/approach – A boundary lubrication protocol was used in the DOE tests to study their tribological behavior. Lubricant additives like PTFE and FeF3 catalyst were used at different concentrations to investigate the wear resistance and the time for a full breakdown under extreme loading conditions. Experiments indicated that new sub-micron FeF3 catalyst plays an important role in preventing the breakdown of the tribofilm. Findings – This paper explores the effect of PTFE and FeF3 catalyst on the performance of fully formulated engine oils. The purpose was to develop equations for minimum wear volume and maximum time for full breakdown. Emphasis was, therefore, given to conditions where the additives were working effectively for minimizing zinc dialkyl dithio phosphate (P per cent). Lubricating oils are normally multi-component additivated systems. They contain different additives such as viscosity improvers, detergents, dispersants and antioxidants. It is known that these additives interact at the surface, affecting the function of the lubricating oil. Therefore, it is important to note that the performance with PTFE and FeF3 catalyst was significantly improved when compared to fully formulated commercial oils used alone. Originality/value – Lubricating oils are normally multi-component additivated systems. They contain different additives such as viscosity improvers, detergents, dispersants and antioxidants. It is known that these additives interact at the surface, affecting the function of the lubricating oil. Therefore, it is important to note that the performance with PTFE and FeF3 catalyst was significantly improved when compared to fully formulated commercial oils used alone.


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