Boundary Lubricating in Low-Pressure Application

[pachard]

Hi,

I'm trying to find theoretical documentation or insight relating to boundary lubrication in a low-pressure application. I'm trying to model the static friction in a system consisting of metal-to-metal contact, wetted by a (somewhat viscous) fluid (sorry I can't disclose the specifics).
The relative speeds of the two metals are not high enough to generate full lubrication.

Thanks!
(First post, I hope to be able to contribute soon!)

 

[TVP]

Good website on all things tribological:

http://www.tribology-abc.com/default.htm

Google Books can be an amazing tool for quick searches on specific technical topics:

http://www.google.com/search?q=boun....,cf.osb&fp=dda2d38c14d9c2b3&biw=1238&bih=569

 

[pachard]

Thanks for the tip. I can assure you I've been searching the web for a few hours now, I only use forums as a last resort...

What I guess I'm really searching for is a theoretical explanation as to what makes a wet surface slippery. I don't know if boundary lubrication is the proper term describing this regime of friction.

 

[ivymike]

boundary lubrication sounds like the right term

You've left open the question of what constitutes "low pressure." 200 bar? 10 bar?

 

[pachard]

The application is a silicone chip resting on a substrate, wetted by a layer of antioxidant flux (before soldering of the contacts); I'm coming up with a rough model of its resistance to displacing disturbances. I would suppose near-atmospheric pressure, probably regulated by capillary forces.

I'm probably going to end up conducting a test isolating the static coefficient of friction of the contacting surfaces, it's just that I don't know what fundamentally causes wet surfaces to exhibit a lower static coefficient than dry ones, since there is no relative movement in the static scenario (or is there?).

Thanks for the help.

 

[MikeHalloran]

Silicon chips don't weigh a lot. You might have to account for buoyancy.


Mike Halloran
Pembroke Pines, FL, USA