Grease flow properties

When molybdenum disulphide is added to a grease, the effect on the flow properties depends critically on the concentration of molybdenum disulphide. Where the quantity added is high enough to cause a major change in the flow properties, the result is a product which no longer behaves as a grease, but behaves like a paste. Such materials are generally used as anti-seize compounds rather than lubricants, and they will be described in Section 13.4. 

Parameters that are important to grease behavior and utility are related to flow properties under pressure (ASTM D-2509, ASTM D-2596, ASTM... 

Abstract Grease lubrication is a complex mixture of science and engineering, requires an interdisciplinary approach, and is applied to the majority of bearings worldwide. Grease can be more than a lubricant it is often expected to perform as a seal, corrosion inhibitor, shock absorber and a noise suppressant. It is a viscoelastic plastic solid, therefore, a liquid or solid, dependent upon the applied physical conditions of stress and/or temperature, with a yield value, ao- It has a coarse structure of filaments within a matrix. The suitability of flow properties of a grease for an application is best determined using a controlled stress rheometer for the frequency response of parameters such as yield, a, complex shear modulus, G phase angle, 5, and the complex viscosity, rj. ... 

As stated above, a grease contains two basic components an oil, which has the flow properties of a liquid and a thickener or gellant, which is a solid insoluble in the oil. It will be shown later that the... 

Properties Yellowish-white free-flowing powder. Completly soluble in hot or cold water. Practically insoluble in oils, greases, hydrocarbons, ketones, esters. Water solutions are tasteless, odorless, nontoxic. Has 5-8 times the thickening power of starch. Reduces the friction drag of water on metals. 

The consistency of a grease is a complex of related properties, easily demonstrable empirically but difficult to define precisely. We can single out yield stress as a truly definable, pertinent property and then have a quantitative parameter in terms of which we can treat consistency. Criddle and Dreher [1] observed typical solid-body stress-strain behavior in greases, with an elastic region, a region of plastic deformation and an ultimate yield or rupture point. At rest grease behaves like a solid body provided the specimen is not too big, it will not flow under the force of gravity. ... 

Silicone compounds are so named to distinguish them from the lubricating greases. They are prepared by milling into a silicone fluid a small amount of a finely divided silica. The result is a greaselike product with purely incidental lubricating properties. It possesses, most of the properties of the silicone fluid except that of flow. 

A creep test was performed to examine the viscoelastic properties of the CNT-grease. A shear stress of 5 Pa was used for 5.0 and 7.0 wt% nanotube loading, while 40 and 100 Pa was used for 10.0 wt% and 12.0 wt% nanotube loading. These stresses were considered to be below that of instantaneous pure viscous flow for each sample. Each creep test was sequenced for 1000 s, followed by a 100 s creep-recovery analysis. 

Uses Silicone for damping, heat transfer, hydraulic fluids, mbber/plas-tics, polishes, cosmetics/toiletries, aq. defoaming prods. thread/fiber lubricant for textiles mold release for tires, rubber, plastics base fluid for greases flow control agent, mar resist, aid, gloss aid in paints Properties Sp.gr. 0.968 vise. 100 cSt pour pt. -67 F flash pt. (PMCC) 575 F ref. index 1.4030 surf. tens. 20.9 dynes/cm sp. heat 0.36 Btu/lb/ F dissip. factor 0.0001 dielec. str. 35 kV dielec, const. 2.74 vol. resist. 1x10 ohm-cm 100% silicone SF96 (350 CSt) [GE Silicones]... 

Definition Natural material derived from the ground endosperms of Cyamopsis tetragonolobus consists of high m.w. hydrocolloidal polysaccharide composed of galactomannan units Properties YIsh.-wh. free-flowing powd. aq. sol ns. tasteless, odorless sol. in hot or cold water insol. in oil, greases, hydrocarbons, ketones, esters m.w. = 220,000... 

Synonyms (4-Nonylphenoxy)-acetic acid (p-Nonylphenoxy) acetic acid Empiricai C17H26O3 Formuia C9H19C6H4OCH2COOH Properties Light amber liq. insol. in water sol. in alkali m.w. 278.39 dens. 1.02 (20 C) vise. 6500 cP flow pt. 5 C Precaution Combustible Uses Corrosion inhibitor for turbine oils, lubricants, fuels, greases antifoam in gasoline, hydraulic fluids, cutting oils... 

Rheology is the study of the deformation and flow of matter in terms of stress, strain, temperature, and time. The rheological properties of a grease are commonly measured by penetration and apparent viscosity,... 

At low temperatures, grease hardens, leading to poor pumpability and rheological properties. Typically the pour point of base oil is considered the low-temperature limit of grease. Below this temperature, the base oil will not flow properly and therefore will not provide sufficient lubrication. 

Uses Antifoam for boiler water treatment, flooring comps. pesticides, weed killers, powd. detergents, powdered food, thickeners, and greases Features Highly effective in most foaming systems outstanding versatility Properties Wh. free-flowing powd Use Level 100-500 ppm... 

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