Physical Properties Of Lubricant Research Articles

Thermal degradation of n-hexadecane base oil and its impact on boundary friction and surface adsorption

The chemical and physical properties of lubricants can alter during use. High temperatures may cause thermal autooxidation of the base oil, which could impact the performance of lubricant additives. Here, the effect of high temperature on the properties of n-hexadecane base oil is investigated. n-Hexadecane undergoes an irreversible transition from high to low boundary friction at 122–134 °C when heated in air. FTIR, UV–vis and NMR spectroscopy indicate the presence of carbonyl- and hydroxyl-containing oxidation products (carboxylic acids, alcohols, esters, ketones and aldehydes). ATR-FTIR shows that iron carboxylates form exclusively inside and around the rubbed friction surface. QCM-D is used to investigate the adsorption of degradation products onto an iron(III) oxide surface and reveals that almost half the adsorbed mass is effectively irreversibly adsorbed.

Influence of Lubricant Physical Property Models on Thermal Elastohydrodynamic Lubrication Solutions

The influence of changes in the physical properties of lubricants on thermal elastohydrodynamic lubrication solutions is examined numerically at the nominal line contact for both Newtonian and non-Newtonian fluids. Specific heat, thermal conductivity, density, and viscosity were considered as functions of temperature and pressure for polyalphaolefin, polyglycol, and mineral oils. It was found that, when considering the physical and rheological properties of lubricants individually, the solutions were over- or under-estimated. The thermal conductivity formula mostly corresponds to solutions for both fluids. The effects of changes in the physical properties of non-Newtonian lubricants were shown to be less than those of Newtonian lubricants. Near-identical qualitative behaviors occurred regardless of oil type under these lubricant models.

Characterization and Performance of Minimum Quantity Lubricants in Through-Tool Drilling

This study characterized airborne microdroplet diameters and size distribution from two commercially available lubricants A and B for internal minimum quantity lubrication (MQL). The effects of air pressure, oil channel size, physical properties of lubricants on the resultant microdroplets and through-tool MQL drilling performance were studied. Airborne microdroplet diameters were highly sensitive to the coolant channel sizes and air pressure. Cluster method was used to divide microdroplets into smaller clusters for comparison. Experimental data show that the average airborne microdroplet of lubricant B was larger than that of lubricant A at different air pressures and channel sizes. The contact angle of lubricant A was at least 10° less than that of lubricant B when depositing on glass or aluminium. High-speed imaging showed the tendency of more viscous lubricant B sticking to the drill tip, and higher pressure and longer time was required to atomize this viscous oil. Built-up-edges were less significant when drilling A380 aluminium with lubricant A. Due to high machinability of A380 aluminium, variation of hole diameter and hole cylindricity were minimal when drilling with different lubricants. Insignificant improvement in hole quality was observed when drilling with excessive amount of MQL lubricants or high concentration of lubricant C in flood coolant.

Common Properties of Lubricants that Affect Vehicle Fuel Efficiency: A North American Historical Perspective

The development of advanced lubricants to improve vehicle fuel efficiency can appear to be as simple as lowering the viscosity and frictional properties of a fluid. However, applied research studies have shown that it is quite difficult to quantify the fuel efficiency properties of advanced lubricants in vehicles. A review of the historical research predominantly performed in North America in this area reveals that there are many factors to consider in order to demonstrate the effectiveness of advanced lubricants. First, the methodology used to measure vehicle fuel efficiency will impact the results since there are many factors not related to the lubricant which will influence vehicle fuel efficiency. Second, developing advanced fuel-efficient lubricants under well controlled conditions overlooks the issue that lubricant properties such as viscosity and friction affect the operating conditions encountered by the lubricant in the vehicle. Finally, the physical properties of lubricants that historically control fuel economy do not have the same effect on fuel efficiency in all vehicles. The proper vehicle or system level test needs to be selected to properly assess the benefits of new advanced lubricants.

Lubricating ability of albumin and globulin on artificial joint implants: a tribological perspective

Albumin and globulin proteins are dominant protein components in synovial fluid, and play important roles in the lubrication mechanism of joint prostheses. The present study investigated the lubricating ability of albumin and globulin on ceramic-on-polyethylene joint implants. A pin-on-disk tribometer was used for friction tests where the experimental condition was replicated with a simulated hip joint condition. The experiment was conducted under three lubricating conditions: bovine synovial fluid (BSF), albumin and globulin. Mechanical properties of specimens and physical properties of lubricant were measured before and after the tests. The experimental results show that albumin yielded a lower friction coefficient as compared to globulin. However, both exhibited a higher friction coefficient and wear rate than that of bovine synovial fluid. This study suggests that further tribological investigations on major biological components of synovial fluid should be carried out, which will help optimise implant design.

Cleaning of lubricating products from machinery parts using subcritical water

Lubricating products composed of hydrocarbon mixtures modified with various thickeners and other additives have been widely used in a large number of machine elements. Cleaning of used lubricants is critical for ensuring the proper machine operations. Conventional cleaning processes, however, involve very toxic, hazardous, and/or persistent organic or harsh aqueous solvents. In this study, an alternative cleaning method was developed using subcritical water. Lubricating oily materials were effectively removed by both liquid and vapor subcritical water extractions at a relatively low operating temperature (∼150°C). The cleaning efficiency was mainly dependent on the physical properties of lubricants. The operating temperature also had a significant impact on the cleaning efficiency since the solubility of subcritical water for the base oil was greatly enhanced due to the reduction of its dielectric constant (€ ∼43 at an operating temperature of 150°C). Upon the results of this study the subcritical water cleaning system demonstrated a potential as an alternative of conventional technologies for the clean-up of lubricants from machinery parts.

潤滑油の高圧物性とトライボロジー

Physical properties of lubricants under high pressure (e.g., density, elastic constant and viscosity) are the fundamental properties for the tribological evaluation (i.e. friction and wear) of rolling bearings, gears and traction drives. This paper introduces the importance of such physical properties of lubricants under high pressure in tribology and the application of a diamond-anvil pressure cell (DAC) for tribological measurements. A falling sphere viscometry in the DAC facilitated the viscosity measurements up to 2 GPa. A photon-correlation technique with laser light scattering in the DAC enabled the viscosity estimation of solidified glassy state lubricants (viscosity is about 109 Pa·s) from structural relaxation. Dynamic elastic moduli were obtained from Brillouin light scattering measurements in the DAC up to 4 GPa, which enabled the evaluation of the frequency dispersion of elastic moduli with quasi-static data.

Properties of Polyol Esters–-Lubrication of an Aluminum Silicon Alloy

The chemical and physical properties of lubricants significantly affect their performance in industrial applications where aluminum is used as a sliding material. The inertness of aluminum contributes to its poor wear resistance. The wear characteristics of a series of polyol esters were evaluated in terms of their chemical structure for the lubrication of an aluminum-silicon (Al-Si) alloy using a pin-on-disc-type wear tester. The molecular structure and the number of acid groups of the polyol esters strongly affected their ability to lubricate the Al-Si alloy. The wear and scuffing performances of the polyol esters with the longer linear-chain acids were better than those of the esters with shorter branched acid chains. For esters of the same number of carbon atoms, neopentylglycol-type esters had higher scuffing loads than trimethylolpropane esters which in turn show better antiscuffing properties than the pentaerythritol esters. The effect of the polarity of the molecules on the friction and wear properties of the polyol esters is discussed using a relative polarity index. Less polar polyol esters were found to have better wear and scuffing protection behavior in lubricating the Al-Si alloy. Oxidation tests in the Penn State Microreactor with Al-Si catalyst specimens showed that the polyol esters were depleted mainly by evaporation losses under an air atmosphere. A consistent trend was observed between the volatility of the polyol esters and their lubrication properties for the Al-Si alloy. Presented at the 51st Annual Meeting in Cincinnati, Ohio May 19–23, 1996

THERMOELASTIC ANALYSIS OF HYDROSTATIC THRUST BEARINGS FOR HYDRAULIC EQUIPMENT

The thermoelastic behavior of hydrostatic thrust bearings is analyzed numerically. Mineral oils, HWCF, sea water, and tap water are studied as lubricants. The physical properties of lubricants are expressed as a function of temperature and pressure. The heat transfer and thermoelastic distortion of the bearing pad are considered. The performance of bearings is evaluated by the load carrying capacity, mass flow rate, and friction torque. The effect of temperature and pressure on the physical properties of mineral oils is greater than that on HWCF, sea water, and tap water. The load carrying capacity is scarcely influenced by the types of lubricant, the angular velocity, and the fluid film profile. The fluid film thickness influences the mass flow rate and the friction torque. The inclination of the bearing pad increases the mass flow rate and the moment-load carrying capacity. The distortion due to pressure in the fluid film increases the mass flow rate.

An Experimental Investigation of the Effect of Lubricant Properties on Temperature and Wear in Sliding Concentrated Contacts

The study reported in this paper is undertaken to investigate the effect of some of the physical properties of lubricants on the contact temperature and wear in heavily loaded Hertzian Contacts under sliding conditions. The surface temperature and wear in a rotating mild steel shaft are measured under different loads applied by a Tungsten Carbide slider. The carbide tip and the shaft are used as part of a dynamic thermocouple system to monitor the contact temperature. Tests are conducted for Hertzian pressures ranging from 1250 to 2140 MPa (1.81×105–3.10×105 psi) and sliding speeds from 0.4 to 1.3 m/sec (943–3142 in./min). Temperature and wear data are given from tests with a heavy duty oil (SAE 80W-90), a high viscosity residual compound, a vegetable oil, and water miscible cutting fluid (0.0476 percent emulsifiable oil by volume). The results show that, for the considered tests, viscosity does not appear to be the significant property of the lubricant temperature rise and wear rate as indicated by the scar depth under similar test conditions.

Paper 14: The Effect of Pressure and Temperature on Some Properties of Fluids of Importance in Elastohydrodynamic Lubrication

Recent advances in the theory of elastohydrodynamic lubrication have greatly increased the demand for information on the physical properties of lubricants at high pressures. Specifically, the viscosity and density and their variation with temperature and pressure enter directly into calculations of the behaviour of lubricants in loaded contacts, whilst for some experimental techniques the dielectric constant at the appropriate conditions is also required. This paper presents measured values of viscosity at pressures up to 15 000 lb/in2 at 30°, 60° and 100°C, and of density and dielectric constant at pressures up to 50 000 lb/in2 at 20° and 100°C for a series of lubricants including mineral, vegetable and synthetic oils. The use of the Clausius-Mosotti relationship to predict dielectric constants at high pressures is shown to be unsatisfactory, and this is demonstrated by application to capacitance measurements obtained in a disc machine.

Lubrication as Affected by Physical Properties of Lubricants

Lubrication as Affected by Physical Properties of Lubricants

NOTES ON THE HISTORY OF LUBRICATION

Journal of the American Society for Naval EngineersVolume 46, Issue 3 p. 369-385 NOTES ON THE HISTORY OF LUBRICATION PART II. JOURNAL BEARING EXPERIMENTS* MAYO D. HERSEY., MAYO D. HERSEY. Division of Engineering, Brown University, Providence, R. I.Search for more papers by this author MAYO D. HERSEY., MAYO D. HERSEY. Division of Engineering, Brown University, Providence, R. I.Search for more papers by this author First published: August 1934 https://doi.org/10.1111/j.1559-3584.1934.tb05144.xCitations: 3 * Part I, General Survey, appeared in the November, 1933, issue. Parts III and IV, to be published later, deal with Physical Properties of Lubricants, and Development of the Theory of Lubrication, respectively. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume46, Issue3August 1934Pages 369-385 RelatedInformation

NOTES ON THE HISTORY OF LUBRICATION

Journal of the American Society for Naval EngineersVolume 45, Issue 4 p. 411-429 NOTES ON THE HISTORY OF LUBRICATION General Survey., General Survey. To be followed by Part II, Experiments on Journal Bearings; Part III, Physical Properties of Lubricants; and Part IV, Development of the Theory of Lubrication.Search for more papers by this authorMayo d. Hersey, Mayo d. Hersey CIVIL MEMBER. Research and Development Division, General Laboratories, Socony-Vacuum Corporation, Paulsboro, N. J.Search for more papers by this author General Survey., General Survey. To be followed by Part II, Experiments on Journal Bearings; Part III, Physical Properties of Lubricants; and Part IV, Development of the Theory of Lubrication.Search for more papers by this authorMayo d. Hersey, Mayo d. Hersey CIVIL MEMBER. Research and Development Division, General Laboratories, Socony-Vacuum Corporation, Paulsboro, N. J.Search for more papers by this author First published: November 1933 https://doi.org/10.1111/j.1559-3584.1933.tb04284.x §References to publications will be found at the end of the article and should be carefully noted by the reader, as the dates and titles are relied upon to convey an interesting part of the story. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume45, Issue4November 1933Pages 411-429 RelatedInformation

Lubrication and Lubricants A Treatise on the Theory and Practice of Lubrication, and on the Nature, Properties, and Testing of Lubricants

THIS work may be divided into two parts, which, in fact, have little connection with one another, The first is that which deals with the chemical and physical properties of lubricants generally, and will appeal more particularly to analytical chemists, to whom samples of lubricants are submitted for the purpose of estimating their commercial value. So far as one can judge, this part of the work is particularly clear; full directions are given for carrying out any of the tests, in order to obtain such things as the free acids. This will, however, hardly appeal to the average user of lubricants, as what he requires is some simple mechanical test which will, more or less, indicate the value of the oil. The second portion of the work deals with the mechanical testing of oil, and also the design and construction of bearings generally, together with the general theory of friction, as given in chapter iv. This is particularly well written, and gives the full theory of lubrication as developed by Osborne Reynolds, Goodman, and Towers, and will repay a careful study. An account is given of the various oil-testing machines as designed by Thurstan, Smith, and Goodman. Judging from our own experience, while these machines when extremely carefully handled give trustworthy results, one is never quite certain as to what is really being obtained; whether it is a test of the lubrication itself, of the materials forming the bearing, or of the condition of the bearing. We should be inclined to say that it would probably be a small part of each, and, moreover, it does not give much idea as to the value of the lubricant for continuous use, which is now the rule for engine work generally. Doubtless, owing to the great length of the book, some 500 pages, the authors have been unable to devote a large space to the design and lubrication of bearings, although they give much useful information as to the composition of bearing metals generally, and also the admissible loads. They do not, however, give the attention to forced lubrication which we consider it deserves. The whole tendency of modern engine practice, either with enclosed or open engines, is to substitute pressure lubrication for gravity, and this has entailed wholly different construction of bearings from those with the ordinary drip lubrication. Lubrication and Lubricants. A Treatise on the Theory and Practice of Lubrication, and on the Nature, Properties, and Testing of Lubricants. By Leonard Archbutt R. Mountford Deeley. Second edition, thoroughly revised and enlarged. Pp. xxxii + 528. (London: C. Griffin. and Co., Ltd., 1907.) Price 21s. net.