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The various physical and surface‐chemical factors which might affect the lubricating action of molybdenum disulphide are discussed; the importance of particle size and shape are emphasized. Up to date thoughts on lubrication mechanism are examined together with various environmental factors which can affect its industrial use. Recent Climax development work, particularly with respect to MoS2 greases concludes the paper.

LONG before man learnt to make fire by the friction of wood, he experienced the burden of friction in dragging home his kill. Perhaps it is not too fanciful to suppose that the torn sides of his beast gave the first solid lubricant. Blood and mutton fat were seriously recommended as lubricants for church bell trunnions as recently as the 17th century. Indoed we still reckon fatty acids the best of all boundary lubricants. The range of man's activities has increased enormously in the present century, and particularly in the last few decades. Men have circled the earth in space; a space ship is on its way to examine another planet; terrestrial man is boring to the bottom of the earth's crust; others have descended to the depths of the ocean, and oven established a home on the floor of the Mediterranean, Speeds have increased by factors of thousands, temperatures range from near absolute zero to thousands of degrees; and a new environment of high‐intensity nuclear radiation has been created. Still, objects must move over and along each other in these exotic conditions; and to a large extent solid lubricants can provide the answer to the frictional problems.

THE AMERICAN Socity of Lubrication Engineers held their first International Conference on Solid Lubrication at Denver, Colorado on August 24—27, 1971 and we give abstracts and salient points from the thirty‐two papers presented. The papers in full have been bound into book form and are available from the ASLE, 838 Busse Highway, Park Ridge, 111. 60068, price $26.00 post paid.

THE DEVELOPMENT of modern cutting and forming machines and new and tougher materials has confronted Production Engineers with numerous problems, one of them being the lubrication of cutting and forming tools.

The advantages of Molybdenum Disulphide powders for dry lubrication under extremes of temperature are well known and these products have solved a great number of extremely dfficult lubrication problems where conventional lubricants have completely failed. It is also known that, although liquid dispersions of Molybdenum Disulphide provide most valuable lubricants for many industrial purposes, it is in dry lubrication that MoS2 has proved the most valuable. This is probably because, hitherto, quasi‐colloidal dispersions lose some of the advantages of the dry powders, possibly due to oxidation. Again, this may, in turn, be due to the fact that the particle size of these powders has, up to now, not been smaller than three‐quarters of a micron and usually ranging from this size up to three microns.

THE LUBRICATING PROPERTIES and industrial uses of Molybdenum Disulphide are sufficiently known and covered in literature to need no comment. It has been known for some years that this solid lubricant, in common with graphite, offers a performance that appears primarily to be related to the amount of impurities present, and secondly to the particle size of the powder, Thus for some industrial lubrication it appears desirable to aim at a size of powder characterised by a maximum number of particles between 1 and 10µ. At the lower end of the scale it would seem that excessive fineness in dispersions (i.e., below 1µ) tends to militate against performance, although for acid refined powders, the upper limit is considerably extended.

The purpose of this study is to examine the impact of MoS₂ on the microstructure and characteristics of micro-arc oxidized (MAO) ceramic coatings created on ZK60 magnesium alloy through the addition of varying concentrations of MoS₂ particles to the electrolyte, aiming to enhance the corrosion resistance of magnesium alloy.

The surface morphology, roughness and phase composition of the coatings were analyzed using scanning electron microscopy, a hand-held roughness tester and an X-ray diffractometer, respectively, and the corrosion resistance of the MAO coatings prepared by the addition of different contents of MoS₂ particles was tested and analyzed using an electrochemical workstation.

The results demonstrate that MoS₂/MgO composite coatings have been successfully prepared on the surface of magnesium alloys through micro-arc oxidation. Furthermore, the corrosion resistance of the ZK60 magnesium alloy prepared with the addition of 1.0 g/L MoS₂ was the best compared to the other samples.

MoS₂ particles were able to penetrate the coatings successfully during the micro-arc oxidation process, acting as a barrier in the micropores to prevent the corrosion medium from touching the surface, thus improving the corrosion resistance of the sample. The electrochemical workstation was used to study the corrosion resistance of the MoS₂/MAO coating on the ZK60 magnesium alloy.

The purpose of this paper is to formulate heavy-duty lithium complex grease using low molecular weight poly tetra fluoro ethylene (PTFE) micro-particles as extreme pressure (EP) additive manufactured by E-beam scissoring and ultra-high speed grinding process of pre-sintered PTFE scrap.

Lithium complex grease is formulated with PTFE micro-particles, and optimum treat rate was studied by standard bench tests by ASTM D 2266 and IP-239 for tribological properties and compared with commercially available Molybdenum Di sulphide (Moly)-based lithium complex grease. The performance of the grease was further evaluated by a cyclic load test at varying speeds and loads to simulate the operational field conditions.

The lithium complex PTFE grease was manufactured using PTFE micro-particles as EP additive. The PTFE micro-particles dispersed in the lithium complex grease significantly improve the anti-wear performance and load bearing properties. Further, when the product was tested under a cyclic load conditions on standard tribological bench test against commercially available Moly lithium complex grease, shows stable anti-wear properties and reduced coefficient of friction.

The low molecular weight PTFE micro-particles, manufactured in the in-house electron beam (E-beam) and ultra-high speed micronizer facility from a pre-sintered PTFE scrap has been used as EP additive for grease applications for the first time. The results on the cyclic load tests indicate significant performance improvement in retaining the anti-wear and friction properties. Thus, value addition is done in formulating superior performance grease and evaluating under cyclic load conditions similar to field operating conditions and also in creating value added additives by converting the pre-sintered PTFE scarp which is environmental hazard due to poor biodegradability, creating a cyclic economy and a sustainable concept.

INTEREST in tin powder for powder metallurgy is growing; not only does it find a place in non‐ferrous powder metallurgy, as in sintered porous bronzes used for bearings, but it is valuable as a sintering acid in ferrous powder metallurgy. Work at the Tin Research Institute demonstrates the advantages of small additions of tin powder in iron‐copper‐tin compacts for reducing the sintering temperature and increasing the dimensional stability and wear resistance. Tin powders are beingused worldwide for this purpose and not least in Japan.

This study aims to investigate the behavior of vegetable oil with two additives. Base oil’s tribological qualities can be improved with the help of several additions. In the present investigation, soybean oil is served as the foundational oil due to its eco-friendliness and status as a vegetable oil with two additives, named polytetrafluoroethylene (PTFE) and molybdenum disulfide (MoS₂).

As additives, PTFE and MoS₂ are used; PTFE is renowned for its anti-friction (AF) properties, while MoS₂ is a solid lubricant with anti-wear (AW) properties. This investigation examines the synergistic impact of AF and AW additions in vegetable oil. The lubricity of the base oil is measured by using a four-ball tester, and the wear properties of the oil at different additive amounts are determined by using a universal tribometer.

PTFE (at 5 Wt.%) and MoS₂ (at 1 Wt.%) were found to improve the tribological performance of the base oil. The weld load is significantly increased when 5 Wt.% of PTFE + MoS₂ is added to the base oil.

A better tribological characteristic can be achieved by combining additives that amount to less than 1% of the base oil. In experiments with highly concentrated MoS₂, the adequate pressure improved dramatically, but the lubricant’s tribological characteristics did not.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2022-0321/