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The purpose of this paper is to present the tribological, anticorrosion and antirust properties of three 2,5-dimercapto-1,3,4-thiadiazole (DMTD) derivatives as water-soluble additives in water–glycol hydraulic fluid.

DMTD derivatives possessing excellent corrosion inhibiting and extreme-pressure (EP) properties have long been used as metal passivators and load-carrying additives in lubricating oils and grease. However, there are seldom literatures about DMTD derivatives as water-soluble lubricant additives as yet. In this work, three DMTD derivatives were synthesized and investigated as water-soluble additives in the water–glycol hydraulic fluid. Their tribological properties were evaluated in detail by four-ball wear test machine and Optimol SRV-IV oscillating friction and wear tester. Meanwhile, their anticorrosion and antirust properties were also investigated by copper strip corrosive tests and antirust tests, respectively. The worn surfaces were analyzed by scanning electron microscope and X-ray photonelectron spectroscope, and the EP, antiwear and friction-reducing mechanisms were primarily proposed.

The synthesized three DMTD derivatives (coded as A, B and C) have excellent solubility in the base liquid of the water–glycol hydraulic fluid. The experimental results demonstrated that all these compounds, especially A, could remarkably improve the EP, antiwear and friction-reducing properties of the base liquid. Furthermore, they all have perfect copper corrosion inhibiting and antirust properties with low adding concentration (< 3 weight per cent) in the base liquid and hence could be used as multifunctional additives in the water–glycol hydraulic fluid.

This research only focused on the synthesized DMTD derivatives. If possible, some other thiadiazole derivatives also should be investigated.

The synthesized DMTD derivatives, especially compound A, can be used as multifunctional water-soluble additives in the water–glycol hydraulic fluid.

In this paper, three DMTD derivatives were synthesized and their tribological behaviors as water-soluble lubricant additives were investigated for the first time. In addition, the EP, antiwear and friction-reducing mechanisms were also put forward.

In the late 19th century, work attributed to a Mr F. W. Taylor showed that water flooding a cutting area permitted a great increase in cutting speeds. Prior to this cutting was performed dry, at very slow speeds, but it was found that water gave an easier removal of swarf, enabling the cutting speed to be increased by some 40 to 50%. Water, obviously, gave rise to the problems of corrosion.

THE FIRE HAZARD inherent in the use of petroleum based hydraulic fluids for many industrial applications has been such that ‘safe’ fluids were demanded, appeared and are today widely and increasingly used. Their composition is either completely non‐petroleum or includes petroleum fluid in a modified state. In the former category are the phosphate esters or chlorinated hydrocarbon liquids and the water/glycol solutions ; in the latter we find the W/O of ‘inverted’ oil and water emulsions.

A NUMBER of major industrial fires which were fed in part by the petroleum oils used in the hydraulic systems have accelerated the trend towards the use of fire‐resistant fluids in systems located where a fire hazard exists and wherever heat or flame are in proximity to high pressure hydraulic equipment, a fractured pipe line or faulty fitting can result in the hydraulic oil being ejected considerable distances into open furnaces, melting pots, welding torches, etc. It is for all such cases where a true fire hazard exists that the fire‐resistant fluids are now in demand.

This paper aims to synthesize a novel alkanolamine borate and explore the performance of as a copper wire drawing oil.

In this paper, a copper wire drawing oil (CU-KL) was formulated by using a novel alkanolamine borate, naphthenic base oil, fatty alcohol polyoxyethylene ether and palm oil. The tribological performance of CU-KL and commercial copper wire drawing oils (CU-DRB and CU-8010) was investigated

Under applied loads of 5 N-15 N, the average friction coefficient of CU-KL was 29.4%, 5.4% and 25.3% lower than that of CU-DRB, respectively. At sliding speed of 1000–5000 rpm, the average friction coefficient of CU-KL was reduced by 14.3%, 6% and 10.3% compared with CU-DRB, respectively. Through scanning electron microscope and energy dispersive spectrometry, CU-KL can form B-containing compound at the contact interface, which could synergistically enhance the lubrication effect and improve the wear resistance.

The properties of CU-KL under different test condition were studied, and the findings are of great significance for the application of alkanolamine borate in copper wire drawing oil.

THE TERM “synthetic lubricant” has been adopted to designate a variety of fluids, derived from sources other than mineral oils, which have been developed by the technologist in order to satisfy the extreme conditions under which present‐day machinery has to operate : for example, high or low temperatures, or both, often with high bearing loads, and sometimes under conditions which demand resistance to ignition. Although, in fact, modern petroleum oils are prepared to such stringent specifications, and by such carefully controlled processes, that they are almost equally as “tailor‐made”, it is their comparatively limited temperature range that largely brought about the development of the so‐called synthetic product.

The purpose of this study is to reveal the underlying mechanism in film formation of oil-in-water (O/W) emulsion.

This study focuses on the film forming characteristics of O/W emulsion between the surface of a steel ball and a glass disc coated with chromium. The lubricant film thicknesses of O/W emulsion with various mechanical stirring strength were discussed, which were observed by technique of relative optical interference intensity.

The authors directly observed the oil pool in the contact area, finding the size of oil pool was closely related to the film-forming ability of emulsion. Enrichment phenomenon occurs in oil pool, which was caused by phase inversion. Further investigations revealed that the emulsion is stable with strong stirring strength, resulting in a smaller oil pool size and worse film forming ability.

With the wide usage of O/W emulsion in both biological and industrial systems, the ability of emulsion film formation is considered as an important factor to evaluate the lubrication effectiveness.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2022-0354/

KNOWN as Hydromul 100 and Hydromul 68, these stabilized water‐in‐oil emulsions are designed for use as fire resistant hydraulic fluids. They are intended to be used in circumstances where the flammability of a conventional mineral hydraulic oil introduces an unacceptable risk, but where the relatively high cost of water/glycol, phosphate ester, or other synthetic fire‐resistant fluids is not justified.

The main purpose of this paper is the generation of the heat transfer and pressure drop correlations by considering three working fluids, namely air, water, and ethylene glycol, for the wavy plate-fin heat exchangers (PFHEs).

In order to present the general correlations, various models with different geometrical parameters should be tested. Because of the problems, such as difficult, long time, and costly fabrication of the wavy fins in experimental tests, computational fluid dynamics (CFD) calculations can be a useful method for the generation of the heat transfer and pressure drop correlations with eliminating the experimental problems. Hence, the effective design parameters of the wavy plate-fin, including fin pitch, fin height, wave length, fin thickness, wave amplitude, and fin length, and also their levels were recognized from the literature. The Taguchi method was applied to formulate the CFD simulation work.

The simulation results were compared and validated with an available experimental data. The mean deviations of the Colburn factor, j, and Fanning friction factor, f, values between the simulation results and the experimental data were 3.74 and 9.07 percent, respectively. The presented air correlations and experimental data were in a good agreement, so that approximately 95 percent of the experimental data were correlated within ±12 percent. The j factor values varied for the different working fluids, while the f factor values did not sensibly change.

The presented correlations can be used to estimate the thermal-hydraulic characteristics and to design of the compact PFHE with the wavy channels.

This manuscript presents the new correlations for the compact PFHEs with the way channels by considering all the geometrical parameters and the working fluids with the different Prandtl numbers, 0.7, 7, and 150.