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Graphite, Lubricants, Metals
Name: Robert S. B.
Status: educator
Age: 40s
Location: N/A
Country: N/A
Date: 10/2/2004
Question:
Does graphite "bond" to metal? My son is doing a
research paper on "What is a better lubricant for skateboards, graphite,
WD40, or motor oil". I am looking to find out why people do not normally
use graphite as a lubricant when it is such a good one.
Replies:
No, graphite does not bond to metal in the conventional sense. Graphite
sticks modestly well to many substances if you rub or burnish it on. Note
that graphite is corrosive to aluminum in the presence of moisture.
Graphite is what is called a "solid lubricant," and it is a solid that is
slippery. Other solid lubricants include molybdenum disulphide, PTFE
(that is the chemical name for DuPont's Teflon (TM)), and hexagonal boron nitride.
Graphite needs humidity from the air to be slippery. Like all lubricants,
it has advantages and disadvantages depending where and how it is used.
Things you could investigate when comparing lubricants could include: 1)
which material makes rolling easiest for light and heavy loads, 2) which
material keeps lubricating in the presence of dirt, 3) which material works
best to keep the ball bearings from wearing out, and 4) which material keeps
the bearings rolling most smoothly?
Because skateboard wheels roll on ball bearings, the friction will be low.
Also, commercial skateboards use ball bearings with seals on them to keep
the grease in and the dirt out.
Bob Erck
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