Industrial Lubrication and Tribology最新文献

Purpose

The purpose of this paper is to improve the mechanical and tribological properties of Si₃N₄ ceramics and to make the application of Si₃N₄ ceramics as tribological materials more extensive.

Design/methodology/approach

Si₃N₄-based composite ceramics (SN-2L) containing nitrogen-doped graphene quantum dots (N-GQDs) were prepared by hot press sintering process through adding 2 Wt.% nanolignin as precursor to the Si₃N₄ matrix, and the dry friction and wear behaviors of Si₃N₄-based composite against TC4 disc were performed at the different loads by using pin-on-disc tester.

Findings

The friction coefficients and wear rates of SN-2L composite against TC4 were significantly lower than those of the single-phase Si₃N₄ against TC4 at the load range from 15 to 45 N. At higher load of 45 N, SN-2L/TC4 pair presented the lowest friction coefficient of 0.25, and the wear rates of the pins and discs were as low as 1.76 × 10⁻⁶ and 2.59 × 10⁻⁴mm³/N·m. The low friction and wear behavior could be attributed to the detachment of N-GQDs from the ceramic matrix to the worn surface at the load of 30 N or higher, and then an effective lubricating film containing N-GQDs, SiO₂, TiO₂ and Al₂SiO₅ formed in the worn surface. While, at the same test condition, the friction coefficient of the single-phase Si₃N₄ against TC4 was at a range from 0.45 to 0.58. The spalling and cracking morphology formed on the worn surface of single-phase Si3N4, and the wear mechanism was mainly dominated by adhesive and abrasive wear.

Originality/value

Overall, a high-performance green ceramic composite was prepared, and the composite had a good potential for application in engineering tribology fields (such as aerospace bearings).

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0161/

Purpose

The incorporation of phosphide additives is regarded as a highly effective strategy for enhancing the lubricative qualities of base oils. This study aims to assess the lubrication behavior and efficacy of various phosphide additives in polyethylsiloxane (PES) through the employment of the Schwingum Reibung Verschleiss test methodology, across a temperature range from ambient to 300°C.

Design/methodology/approach

PES demonstrated commendable lubrication capabilities within the Si3N4/M50 system, primarily attributable to the Si-O frictional reaction film at the interface. This film undergoes disintegration as the temperature escalates, leading to heightened wear. Moreover, the phosphide additives were found to ameliorate the issues encountered by PES in the Si3N4/M50 system, characterized by numerous boundary lubrication failure instances. A chemical film comprising P-Fe-O was observed to form at the interface; however, at elevated temperatures, disintegration of some phosphide films precipitated lubrication failures, as evidenced by a precipitous rise in the coefficient of friction.

Findings

The results show that a phosphide reactive film can be formed and a reduction in wear rate is achieved, which is reduced by 64.7% from 2.98 (for pure PES at 300°C) to 1.05 × 10^–9 μm³/N m (for triphenyl phosphite at 300°C).

Originality/value

The data derived from this investigation offer critical insights for the selection and deployment of phosphide additives within high-temperature lubrication environments pertinent to PES.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0139/

Purpose

This study aims to understand the influence of raceway surface topography on the temperature rise characteristics of silicon nitride (Si₃N₄) full ceramic ball bearing and improve its service life.

Design/methodology/approach

The arithmetic average height S_a, skewness S_sk and kurtosis S_ku in the three-dimensional surface roughness parameters are used to quantitatively characterize the surface topography of the raceway after superfinishing. The bearing life testing machine is used to test the Si₃N₄ full ceramic ball bearing using polytetrafluoroethylene (PTFE) cage under dry friction conditions, and the self-lubricating full ceramic ball bearing heat generation model is established.

Findings

With the decrease of S_a and S_sk on the raceway surface and the increase of S_ku, the average height of the raceway surface decreases, and the peaks and valleys tend to be symmetrically distributed on the average surface, and the surface texture becomes tighter. This kind of raceway surface topography is beneficial to form a thin and uniform filamentous PTFE transfer film with a wide coverage area on the raceway surface based on consuming less cage materials and improving the temperature rise characteristics of hot isostatic pressing silicon nitride full ceramic ball bearings.

Originality/value

The research results provide a theoretical basis for the reasonable selection of Si₃N₄ ring raceway processing technology and have important significance for improving the working characteristics and service life of Si₃N₄ full ceramic ball bearings under dry friction conditions.

Purpose

This study aims to explore the synthesis and tribological performances of di-n-octyl sebacate (DOS) synthesized with spherical nano-MoS₂/sericite (SMS) and carboxylated SMS (CSMS) as catalysts.

Design/methodology/approach

SMS and CSMS were used as esterification catalysts to synthesize DOS from sebacic acid and n-octanol. The two catalysts were in situ dispersed in the synthesized DOS after the reaction to form suspensions. The tribological performances of the two suspensions after 20 days of storage were studied.

Findings

CSMS was more stably dispersed in DOS than SMS, and they reduced friction by 55.6% and 22.2% and wear by 51.3% and 56.5%, respectively. Such results were mainly caused by the COOH on CSMS, which was more conducive to improving the dispersion and friction reduction of CSMS than wear resistance. Another possible reason was the difference between the dispersion amounts of CSMS and SMS in DOS. The sericite of SMS was converted into SiO₂ to enhance wear resistance, while that of CSMS only partially generated SiO₂, and the rest still remained on the surface to reduce friction.

Originality/value

This work provides a more effective SMS catalytical way for DOS synthesis than the traditional inorganic acid catalytical method. SMS does not need to be separated after reaction and can be dispersed directly in DOS as a lubricant additive. Replacing SMS with CSMS can produce a more stable suspension and reduce friction significantly. This work combined the advantages of surface carboxylation modification and in situ catalytic dispersion and provided alternatives for the synthesis of DOS and the dispersion of MoS₂-based lubricant additives.

Purpose

The purpose of this study is to create sustainable additives for future vehicles, characterized by low levels of sulfated ash, sulfur and phosphorus (SAPS) or even SAPS-free alternatives. These newly developed additives must not only match or outperform the current commercial benchmarks in terms of tribological performance, but also align with the emerging sustainability trends. It is anticipated that this innovative technology will yield promising outcomes in the realm of hybrid and electric vehicles.

Design/methodology/approach

This research primarily focused on chemical synthesis, performance evaluation and characterizations. These aspects were studied through collaboration between Syensqo, Southwest Research Institute (the USA) and the Lab of the Future in France. The data was generated and analyzed by a team of research scientists, internship students and technical specialists.

Findings

Two types of additives have been specifically designed and synthesized in accordance with sustainable requirements. Both technologies have exhibited exceptional frictional and wear-resistant properties. Moreover, the leading candidates exhibit a lower rate of copper corrosion, stable electric conductivity and outstanding thermal stability when compared to commercial benchmarks. This study is expected to open a new research avenue for developing next-generation additives for lubricants, with wide potential applications including hybrid electric vehicle and electric vehicle markets.

Originality/value

In the current lubricant market, there is a lack of effective low-SAPS or SAPS-free additives. This research aims to address this gap by designing sustainable additives for next-generation vehicles that not only meet specific requirements but also maintain optimal lubrication performance.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2024-0033/

Purpose

The need for materials with superior mechanical and physical properties has recently increased. Inconel 718, one of these superalloys, is frequently used in the aviation and space industry. However, during Inconel 718 superalloy machining, cutting tools and cutting fluid were excessively consumed. This study aims to investigate using an innovative and environmentally friendly cutting fluid in milling the Inconel 718 superalloy.

Design/methodology/approach

In this study, a Borax- (BX-)added cutting nanofluid was prepared and used for the first time as a coolant in the minimum quantity lubrication (MQL) system of Inconel 718’s face milling process. Response surface methodology (RSM) was used to determine the effect of the BX element on cutting performance. Face milling operations were carried out by adding BX elements at 1.5% and 3% at two different rates.

Findings

As the BX additive ratio in the cutting fluid used in the MQL system increased, the cutting force values decreased. The lowest cutting force value was measured in the tests with cutting fluid containing 1.5% BX. In addition, a smoother surface was obtained by adding 1.5% BX to the cutting fluid. Furthermore, cutting tool life increased by 20% compared to 0% by 3% BX nanofluid concentration.

Originality/value

The study is innovative regarding the material processed, the cutting fluid used and the method used for the aerospace industry.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0191/

Purpose

The purpose of this study is to investigate the sealing performance of different deep groove mechanical seals by considering the changing law of dynamic pressure effect and temperature gradient caused by high speed and high pressure.

Design/methodology/approach

A thermohydrodynamic lubrication model (THD) of the mechanical seal was constructed and solved using the commercial software FLUENT. The pressure and temperature distributions of the fluid under different groove types, as well as the sealing performance under different pressures, rotational speeds and sealing gaps, are obtained.

Findings

The annular groove (AG) can effectively reduce the temperature, and the T-type spiral groove (STG) can effectively inhibit the leakage. The increase of pressure and rotational speed leads to the enhancement of dynamic pressure effect and the increase of leakage, while the sealing gap increases and the leakage increases while taking away more heat. The choice of groove type is very important to the impact of sealing performance.

Originality/value

In consideration of the beneficial effect of deep grooves on cooling performance, the viscous temperature equation and the impact of the thermodynamic lubrication model are evaluated in conjunction with the sealing performance of four distinct groove types. This approach provides a theoretical basis for the optimal design of mechanical seals.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0184/