Control of frictional characteristics of lubricants with chemical additives

Control of frictional characteristics of lubricants with chemical additives

AUTHORS’ABSTRACTS VOL. 2 @958/59) 7r Reactive gases were capable of providing effective boundary lubrication with several alloys under the conditio...

155KB Sizes 0 Downloads 27 Views

AUTHORS’ABSTRACTS

VOL. 2 @958/59)

7r

Reactive gases were capable of providing effective boundary lubrication with several alloys under the conditions of these experiments. Chemical

Atmosphere

Effects

in the

Frictional

Behavior

of Molybdenum

Disulfide

A. J. HALTNERANU C. S. OLIVER (General Electric Research Laboratory, Schenectady, New York). A study of the frictional behavior of Moss has been undertaken to learn more in detail about the effects of the atmosphere in which sliding takes place. It is of particular interest to see if there is some correlation with the effects of adsorbed vapors on other solid lubricants. Frictional data obtained in nitrogen in the prescence of water vapor suggest that a number of competing processes may be occurring. Sliding in the presence of water vapor produces hydrogen sulfide, and this indicates that a chemical reaction may account for the increase in friction. Some interesting transient effects are also observed, and these are interpreted as indications that additional processes are influencing the frictional behavior. Surface

Friction

and Dynamic

Mechanical

Properties

of Polymers

A. M. BUECHEANDD. G. FLOM(General Electric Research Laboratory, Schenectady New York). Results are presented of experiments on the lubricated sliding of metals on polymers over a range of speeds and temperatures. These results indicate a correlation between the frictional behavior of materials and their bulk mechanical properties. Support for the experimental correlations is presented in the form of a theory relating the coefficient of rolling friction to bulk mechanical properties. The theory may also be expected to apply to perfectly lubricated sliding where shearing forces have been minimized. Under the conditions of lubrication most commonly encountered, the sliding friction may be expected to consist of the sum of the physical property contribution and a shearing energy term. Control

of Frictional

Characteristics

of Lubricants

with

Chemical

Additives

STANLEYR. SPRAGUEAND RICHARD G. CUNNINGHAM (Shell Oil Company, Wood River Research Laboratory, Wood River, Ill.). Special antifriction lubricants are required for noise-free operation of many mechanisms containing wet clutches, particularly automatic transmissions. The design of such fluids is unique in the field of boundary lubrication in that friction level and response to sliding velocity are of critical importance. During clutch engagement antifriction action is required to minimize frictional vibrations ; but following “lockup” a minimum static friction level must be maintained to prevent continuous clutch slippage. The control of lubricant friction characteristics has been studied in detail in laboratory apparatus. The importance of additive agents, additive concentration,

LITERATURE AND CURRENT EVENTS

72

VOL. 2 (r95%9)

sliding speed, surface materials, bulk oil temperature and interaction is illustrated. In practical applications the antifriction additives are frequently

of these factors, subject

to oxi-

dative and thermal degradation. Experimental data are presented showing that antifriction additive stability and also interaction with other functional additives must be carefully considered in the development of antifriction fluids. Relationship Part

between

I: Friction

Lubricant

and Wear

Oxidation

Reduction

and Wear.

by Fatty

Acid

Lubricants

C. N. ROWE, R. S. FEIN AND K. L. KREUZ (The Texas Company, Beacon, N. Y.). Friction and wear performance of cetane and dilute solutions of fatty acids in cetane were studied with the Four-Ball Wear Machine. IZesults suggest that, after the initial stages of run-in, effective lubrication is provided by resinous soap-containing material formed on the wearing surfaces rather than by an oriented close-packed film of simple acid or soap molecules. Lubrication degrades when bulk lubricant oxidation becomes appreciable. It is postulated that the oxidation increases friction and wear because it causes the resinous lubricant film to (I) become sufficiently thick that it is easily rubbed from the wearing surfaces or (2) dissolve or disperse in the increasingly polar bulk lubricant. Relationship Part

between

II: Lubricant

Lubricant

Oxidation

Oxidation

in Wearing

and

Wear.

Systems

C. 5. ROWE, R. S. FEIN AND K. L. KREUS (The Texas Company, Beacon, In an effort to elucidate the mechanisms oxidation

of cetane and dilute solutions

tubes and compared

with that

infrared absorption for catalytic

of lubricant system.

Oxidation

catalytic.

Further,

lubricant

oxidation

soap-containing

materials

Fourth of Lubricant

Motors Corporation, The operating wet clutches test

equipment paraffinic

and

Detroit,

characteristics

on the Friction

Lubricants of mechanical

the

of Steel on Steel

Department,

Research

Staff,

General

devices such as friction drive units and

composition.

conditions

have shown that naphthenic oils, that synthetic

surfaces.

Mich.).

by lubricant

simulates

on wearing

oxidation

are dispersed or dissolved

(Herman E. Ries, Jr.. Presiding)

Composition

are affected which

formed

Session

FRED G. ROUNDS (Fuels

and that the promotion

there is strong evidence that the enhanced

occurs in the bulk phase. It appears the principal catalysts

bench

by

activity.

is principally

Influence

was followed

Iron, iron oxide powders and wear debris were studied

The results show that wear promotes

resinous

N. Y.).

in wearing systems,

of stearic acid in cetane was studied in glass

in a wearing

techniques.

oxidation

at the

Friction

data obtained

rubbing

surfaces

with a

in full-scale

oils give higher kinetic

friction

values than

oils give a wider range of kinetic

friction

values than

mineral oils, and that some additives lower kinetic friction and/or raise or lower static