I am new to tribolgy and am having to learn rapidly ( internet and physical testing ) for a new product. Can anyone explain in simple terms what adhesion is and how it can be measured within different oils - Tellus, EP etc., Do all oils have adhesion and is there an index similar to the VI which compares them ? I require this information so that I can specify the scope of oils required. Any help will be appreciated.

Adhesive Wear is usully cause by a combination of lubricant spec, loading and contamination, with the lab work we do not often see adhesive wear with out some type of contaminate and/or heavy loading on the application, adhesive commences as micro welding "plucking" minute metal particles off the opposing wear surface, adhesive wear is never good and if not rectified will cause severe damage,
the cleaness level of the applications is the best prevention.

Hi Pat,
I'll assume the property you are refering to "adhesion" is in terms of how well the lubricant adheres to the material being lubricated. There are a bunch of properties that contribute to the lubricant material sticking to the base material. One of the natural ones is a property refered to as Van der Whal forces wich is basically the lubricants inherent charge that helps it to attract itself to an opposing charge, these are contributor properties.There are also additaves called tackifiers that help the lubricant stick to the base material being lubricated and also to itself. There are lubricity additaves that again have a polar attraction to the surface of the metal. How readily a lubricant creates a surface layer is a feature of the lubricant but I don't know of any particular ASTM type of test that is accepted as being an important parameter in specifying a lube. Having said that, the property of covering the surface is exceptionally important.

regards.....