Summary for metal rubber friction Discussion
Reducing coefficient of friction between metal and rubber is the core issue in Jeremy Wiggins’s question about a dynamic O-ring moving in pistoning motion against metal walls, with cost only a mild factor and temperatures ranging from room temperature down to rare exposures around -40 to -70 °C. The answer given says the most common traditional coating is hard chrome plating. According to the responder, chrome provides a lower coefficient of friction than steel, and its microcracks can retain lubricant, which may help in this kind of sliding service. The reply is brief and does not compare other coatings or polishing methods in detail, but it clearly points to hard chrome as a standard starting option for reducing friction in the metal-rubber interface.
Q. I have an application I’m researching, and essentially I’m trying to find the method (coating, mechanical polishing, etc.) that best reduces the coefficient of friction between a dynamic o-ring and the metal walls it operates in, as in a pistoning motion. Cost being a mild factor and temperature ranging from slightly warmer than room temp down to rare exposures of negative 40-70° C (i.e. liquid CO2).
Jeremy Wiggins
– Land O Lakes, Florida, USA
May 6, 2012
A. Hi Jeremy.
Probably the most common traditional coating is hard chrome plating. The chrome offers a lower coefficient of friction than steel, and the microcracks hold lubricant. An interesting demo I saw decades ago, but never forgot, involved a small cone-shaped hard-chrome plated item that the lecturer placed base down / point up on his desk and defied anyone to pick it up :-)
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
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May 7, 2012