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The purpose of this study is to reveal the friction reduction performance and mechanism of granular flow lubrication during the milling of difficult-to-machining materials and provide a high-performance lubrication method for the precision cutting of nickel-based alloys.

The milling tests for Inconel 718 superalloy under dry cutting, flood lubrication and granular flow lubrication were carried out, and the milling force and machined surface quality were used to evaluate their friction reduction effect. Furthermore, based on the energy dispersive spectrometer (EDS) spectrums and the topographical features of machined surface, the lubrication mechanism of different granular mediums was explored during granular flow lubrication.

Compared with flood lubrication, the granular flow lubrication had a significant force reduction effect, and the maximum milling force was reduced by about 30%. At the same time, the granular flow lubrication was more conducive to reducing the tool trace size, repressing surface damage and thus achieving better surface quality. The soft particles had better friction reduction performance than the hard particles with the same particle size, and the friction reduction performance of nanoscale hard particles was superior to that of microscale hard particles. The friction reduction mechanism of MoS₂ and WS₂ soft particles is the mending effect and adsorption film effect, whereas that of SiO₂ and Al₂O₃ hard particles is mainly manifested as the rolling and polishing effect.

Granular flow lubrication was applied in the precision milling of Inconel 718 superalloy, and a comparative study was conducted on the friction reduction performance of soft particles (MoS₂, WS₂) and hard particles (SiO₂, Al₂O₃). Based on the EDS spectrums and topographical features of machined surface, the friction reduction mechanism of soft and hard particles was explored.

This study aims to improve the lubrication performance of molybdenum disulfide powders at textured surface of cemented carbide materials, a squeeze motion of vibration assistance method was introduced and investigated.

Surface texture was fabricated on YT15 cemented carbide samples using a laser marking machine. After that, a tribological experiment was carried out on a self-built friction testing machine under different amplitude and frequency of squeeze motion conditions. Moreover, a simulation model was also established to verify the principle of squeeze motion on the lubrication performance improving of MoS₂ particles at textured interfaces.

Analysis results indicated that surface texture on test sample can increase the storage ability of solid lubrication particles, and the lubrication film at the contact interface is more easily formed due to the reciprocating action. Squeeze motion can improve the storage ability of it due to an intermittent contact, which provides an opportunity for MoS₂ particles infiltration, and then a more uniform distribution and load-bearing properties of force chain are also established and formed simultaneously. Thus, a better tribological performance at the contact interface is obtained.

The main contribution of this work is to provide a reference for the molybdenum disulfide powder lubrication with textured surface of cemented carbide materials.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0166/

Carbon steel has a high application rate in modern industry, but this type of steel has the defect of high wear. This study aims to improve the surface friction and wear performance of carbon steel under such working conditions.

In this study, a dry film lubricant based on graphite powder was prepared by the ultrasonic dispersion method, and deposited on the surface of carbon steel specimens by the simple pressure spraying technology. At the same time, molybdenum disulfide and polytetrafluoroethylene dry film lubricants were developed by the same method, and the comparative experimental study on friction and wear was carried out in the end-face friction tester.

The results show that the deposition effect of graphite and molybdenum disulfide dry film lubricants on the surface of carbon steel is obviously better than that of polytetrafluoroethylene dry film lubricant. Compared with molybdenum disulfide and polytetrafluoroethylene dry film lubricant, graphite dry film lubricant has the best friction and wear performance on the surface of carbon steel. The working life of carbon steel specimens sprayed with graphite dry film lubricant decreases with the increase of pressure load and rotation speed. The combination of load and sliding speed will accelerate the transition of the coating to a stable direction. In addition, the micro lubricant particles formed in the wear process will form particle flow lubrication, and the appropriate addition of particle powder of the same material will also prolong the normal antifriction time of the lubricant.

These findings developed a dry film lubricant that can effectively improve the friction and wear properties of carbon steel surface.

The purpose of this paper is to study a new liquid-phase assisted texture treatment method to improve the tribological properties of 304 stainless steel.

Three groups of textured type (KY, KJ and YJ) were prepared on 304 stainless steel surface using laser circular and cross scanning method in air and liquid assisted condition. The surface morphology and element content of test samples were measured with scanning electron microscope, energy spectrum. Then, the tribological test was carried out using MWF-500 reciprocating friction and wear testing machine under dry and oil lubrication condition.

The experimental results showed that the textured surface of laser processing in air was obviously blackened, and the oxygen content was increased from 16.9% to 24%. These cases did not occur on liquid-assisted laser textured surface, which induced a better wettability and surface texture processing quality. For friction test, the friction coefficient of cross-scanning textured surface prepared in assisted liquid (YJ) was the smallest. It is reduced by 55% in oil lubrication case compared to the original surface (YS). The cross-scanning textured surface prepared in air (KJ) was a little worse in friction coefficient and a little better in wear quantity than the cross-scanning textured surface prepared in assisted liquid (YJ). It is indicated that the laser processing surface with assisted liquid has obvious advantages in surface texture quality and interfacial tribological property. The main reason is that the assisted liquid plays a role in cooling and protecting action of the machined surface. The bubbles, generated at the solid–liquid interface because of the laser heat effect, scatter the laser beam and carry out the processed melt meanwhile. The lubricating medium is easier to penetrate and store in the contact interfaces because of the higher surface textured performance and wettability.

The main contribution of this work is in providing a new surface texture processing method that has a better surface micropits quality and interfacial tribology regulation ability.

This paper aims to clarify the fluid infiltration mechanism at the micro-contact zone boundary of rubber-glass interfaces.

An in situ observation instrument was putted up; then the fluid infiltration process was recorded. Experimental results indicated that the fluid infiltration was more likely to occur in a high-contact-area-ratio zone, and the path order of fluid infiltration was first inner normal to the boundary of micro-contact area, and then along the boundary, at last external normal to the direction of boundary.

By analysis, capillary pressure is the driven force of fluid at interfaces. The micro-channel size at higher-contact-area-ratio zone is smaller, and the capillary pressure is bigger. Moreover, along different section directions of wedge-shaped region, the horizontal driving force of fluid is different due to difference of conical angle.

The main contribution of this study is proposing a new wedge-shaped model for better understanding the phenomena of fluid infiltration at rubber contact interfaces.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0453

The purpose of this paper is to examine empirically how managers establish ethical guanxi (interpersonal relationships) with their business partners to prevent potential ethical incidences in Chinese and Western business contexts.

The present study is guided by a qualitative, abductive approach and draws on in-depth interviews with ten senior managers in five urban New Zealand organisations.

The results point out that guanxi (interpersonal relationships) purely working through renqing (reciprocity) is not sustainable, because it perpetuates a never-ending cycle of favours, once exchanging favours stopped or disappeared, then business relationships dwindled. To establish an ethical guanxi model, the authors found that xinyong (trust) is the foundation, and its enlargement stimulates lijie (empathy) that transfers pure business relationships to a genuine friendship which enhances ethical decision-making. They also posit that once managers are embodied with lijie, then they will have the virtue of ren to behave like junzi (ideal Confucian ethical person) whose business actions tend to be intrinsically guided by a sense of obligation to do something right that will work for diverse stakeholders’ interests, for the prosperity of organisations and society.

This study suggests that managers should take Confucian virtues of xinyong (trust) and lijie (empathy), because they will trigger ren (humanity) as an intrinsic value. In this way, it is more likely for them to become junzi (ideal Confucian ethical person) whose business actions are intrinsically guided by a sense of obligation to do something right that benefits various stakeholders, organisations and society.

This study contributes to the extant literature on preventing ethical incidents of guanxi (interpersonal relationships) by drawing a framework of ethical guanxi, which is built on Confucian virtues of xinyong (trust), lijie (empathy) and ren (humanity). Further, this paper strongly suggests that companies should educate their staff to become more humane to make moral decisions in daily management practice.

This paper aims to discuss the effect of frontline employees' emotional labor (surface acting vs. deep acting) on customer satisfaction and the moderating role of responsibility attributions in the situation of robot service failure.

The scenario-based experimental method was designed to perform hypothesis testing and SPSS was used to analyze the data from the 363 questionnaires collected.

The results indicate that (1) employees' emotional labor recovery has a double-edged sword effect. Deep acting improves customer satisfaction, while surface acting undermines the effectiveness of service recovery and leaves customer satisfaction below previous levels. (2) Customers' responsibility attributions for service failure moderate the effect of service recovery.

To the best of the authors’ knowledge, this is the first study to focus on the role of frontline employees' emotional labor in robot service failure contexts, which not only enriches and expands the relevant literature in this domain, but also deepens the understanding of how emotional labor and responsibility attribution effect the customer satisfaction.

In this paper, the authors aim to study the effect of hydrogen on the pitting corrosion behavior of Incoloy 825, a commonly used material for heat exchanger tubes in hydrogenated heat exchangers.

The pitting initiation and propagation behaviors were investigated by electrochemical and chemical immersion experiments and observed and analyzed by scanning electron microscope and energy dispersive spectrometer methods.

The results show that hydrogen significantly affects the electrochemical behavior of Incoloy 825; the self-corrosion potential decreased from −197 mV before hydrogen charging to −263 mV, −270 mV and −657 mV after hydrogen charging, and the corrosion current density increased from 0.049 µA/cm² before hydrogen charging to 2.490 µA/cm², 2.560 µA/cm² and 2.780 µA/cm² after hydrogen charging. The pitting susceptibility of the material increases.

Hydrogen is enriched on the precipitate, and the pitting corrosion also initiates at that location. The synergistic effect of hydrogen and precipitate destroys the passive film on the metal surface and promotes pitting initiation.

The purpose of this study is to develop the existence and mechanism of stress corrosion cracking (SCC) for A517 steel in marine environments.

Slow strain rate test (SSRT) and constant load tests were used to investigate the SCC susceptibility of A517 steel. In addition, the additive stresses caused by the corrosion film and hydrogen entering into steel were applied to reveal the fundamental mechanism of the SCC.

The SCC susceptibility increased due to anodic dissolution and additive stress caused by the corrosion-produced film under anode polarization. Furthermore, the SCC susceptibility increased with increasing cathodic polarization, which is due to the increased additional stress caused by hydrogen entering into the steel. However, when the cathode polarization further increased, the additional stress remained due to the constant hydrogen content, thus the SCC susceptibility did not vary. Moreover, the SCC susceptibility of A517 steel under an alternate immersion environment (AIE) was lower than that under a full immersion environment and the steel under the AIE with 0.5 W/D had the lowest SCC susceptibility.

The stress corrosion behaviors of A517 in marine environments under various conditions were systematically analyzed.

The chemical behaviour within the occluded cell of simulated cast iron artefact in 3.5 percent NaCl solution has been investigated by means of a simulated occluded cell. It was observed that the pH value and the amount of Cl⁻ migration in the occluded cell were related to the quantity of passing electric current. Electrochemical techniques were capable of providing information on the behaviour of the cast iron in a simulated occluded cell at various time intervals. The results of potentiodynamic polarisation and impedance measurements indicated that corrosion potentials became more negative and the cast iron was corroded more seriously. SEM micrographs clearly revealed the morphologies of specimens after simulated occluded cell galvanostatic tests for different time intervals at 1 mA/cm² anodic current density. An auto‐catalysing process was responsible for the enrichment of chloride ions in occluded cell which was confirmed by Energy Dispersive Spectroscopy (EDS).