[CAUT] Coefficients of Friction

[John Delacour]

At 11:53 pm +0100 18/4/07, I wrote:

>I notice that Ron Overs' bridge, posted the other day, is not 
>graphited and appears to be lacquered all over, though this may be a 
>false impression.  I have no figure for the coefficient of friction 
>between hard nickel and cast steel, but I imagine Ron has done 
>experiments to establish this.

I have now discovered a site where µ for steel/electroless nickel is 
given as 0.3, which is indeed slightly lower than brass and bronze. 
Here is the link

<http://www.chromplate.com/electroless_nickel.html>

Just as interesting, if not more so, is the mention of this 
"relatively new" process:

"__Electroless Nickel/Teflon Composite__
    Teflon adds to the already slick surface of the electroless 
nickel, yielding a very low friction surface. This product is a 
relatively new one. It consists of microscopic beads of Teflon 
co-deposited up to 20% with the electroless nickel. This finish can 
be the solution to sticking, galling or drag problems with moving 
parts, or heated seal surfaces. In some cases, liquid lubricants can 
be eliminated with the use of Nickel/Teflon plating."

JD