On Sun, 22 Jun 2003 22:28:50 GMT, "Peter Cole" <
[email protected]> wrote:
>DO you have any proof that they do either?
These dry additives are widely used in prepackaged products or as additives in applications
where wear is critical to avoid (automotive, heavy equipment, firearms, spacecraft). Here is an
excerpt from one study I took a little time to find:
A laboratory project, sponsored by the Infrastructure Technology Institute at Northwestern , was
initiated in October, 1996 to study the effect of various lubricants on the wear and corrosion of
metals recommended for bridge pin and eyebar connections. Wear was measured using an oscillating pin
rubbing against a stationary disc with a computer controlled Falex Test Machine. Corrosion tests
were run in a salt fog chamber using a 5% sodium chloride solution. Several greases and metals were
tested. The least wear was found with a mineral based grease containing a molybdenum disulfide solid
lubricant (Dow Corning
1121)...
...The following greases were evaluated:
Modil AW2 -- a mineral oil based fluid with a lithium complex soap thickener. The supplier claims
this grease gives excellent wear protection under heavy loads and protects against rust and
corrosion.
Modil 1500 -- a synthetic based fluid with a lithium complex soap thickener. Mobil states that this
grease provides outstanding protection against wear and corrosion at slow speeds under heavy loads.
Pitt-Penn Wheel Bearing Grease -- a mineral oil based fluid with probably a calcium or lithium soap
thickener. This grease was used as a control fluid in the test program.
Prolong EP-2 Grease -- a mineral oil based fluid containing proprietary additives which are claimed
to have extreme pressure protection against wear and prevent rust and water washout.
Dow Corning 3451 -- a fluorocarbon thickened fluorosilicone grease. Dow Corning recommends this
grease for use at high temperatures under heavy loads.
Dow Corning 1292 -- a urea thickened fluorosilicone grease. Claimed to have good high temperature
and load properties.
Dow Corning 1121 -- a molybdenum disulfide filled mineral oil clay-thickened grease. Dow Corning
recommends this grease for use in low speed, high loading applications.
Also, from a moly supplier, admittedly beating their own drum:
"Moly" is molybdenum disulfide, a chemical compound with the symbol MoS2. Moly is the term commonly
used in the lubricants industry. Moly was first used as a lubricant as early as the 17th century,
but its merits were not fully appreciated until aerospace researchers, during the 1940's and 1950's,
discovered its unique ability to function in the extreme environment of deep space. It was during
this time that Climax Molybdenum Company, the principal supplier of molybdenum products worldwide,
introduced lubricant-grade moly on a commercial scale. Since that time, moly lubricants (greases,
fluids, and dry films) have proven themselves in a wide variety of military, industrial, off-highway
(construction and mining), and automotive applications.
The lubricating properties of moly come from its structure of stacked plates. Each moly particle, on
a microscopic scale, can be visualized in simple terms as a series of buttered bread slices one on
another. The bread represents layers of molybdenum atoms and butter represents layers of sulfur
atoms. The bread and butter units align themselves parallel to the metal surfaces in contact and
adhere by mechanical and physical forces to the peaks and valleys of the metal surfaces. Because the
butter layers are weak, the layers of the bread and butter easily slide sideways on each other while
still adhering to the opposed metal surfaces. Metal-to-metal contact is minimized because the moly
fills in the peaks and valleys, and it creates a protective film over the metal surface.
Exceptionally smooth contact surfaces are established as the moly film develops, thus reducing
friction, wear, and its attendant rise in temperature. The moly film is not permanent, but it can be
replenished from the moly contained in the bulk lubricant.
You got to be very careful if you don't know where you're going, because you might not get there.
- Yogi Berra