Just trying to get a handle on how these oil additives interact with each other, and what exactly is happening on the surface.
According to what I have read, AW (ZDDP for example) forms an ablative layer on the metal surfaces to protect the metal under non-EP conditions, but where hydrodynamic lubrication breaks down and boundary conditions occur.
EP adds (Moly for example) is similar, but kicks in when loads become well...extreme, and the EP ablative layer on the mating surfaces shear away instead of the base metal.
How do these interact? Are AW coatings "taller" than EP coatings therefore buffering contact surfaces under less than EP forces? I assume that AW films are stripped away first when EP conditions are met, and then the EP coating is engaged? Why wouldn't EP coatings be enough since they seem to the same thing only better?
Also, there is only so much surface area on any given metal surface, so do these compounds compete for space? When you add polar esters to the mix, this question seems to become even more complicated. Will the esters "stick" to the surface through all the ablative layers that have been built up? Add in corrosion inhibitors and the complexity factor goes up yet again.
Metal surfaces of course are not smooth at the microscopic level. What effect does this have on the ablative coatings? The main page on this board shows that moly has somewhat of a "filler" property to even out the asperities on the metal surface (which should increase base oil film strength), does that mean that AW coating are only effective at the "peaks" of the asperities?
Lots of questions I know, but after months of reading this board and elsewhere, I have not found answers to these questions. Any insight by people "in the know" would be appreciated.
According to what I have read, AW (ZDDP for example) forms an ablative layer on the metal surfaces to protect the metal under non-EP conditions, but where hydrodynamic lubrication breaks down and boundary conditions occur.
EP adds (Moly for example) is similar, but kicks in when loads become well...extreme, and the EP ablative layer on the mating surfaces shear away instead of the base metal.
How do these interact? Are AW coatings "taller" than EP coatings therefore buffering contact surfaces under less than EP forces? I assume that AW films are stripped away first when EP conditions are met, and then the EP coating is engaged? Why wouldn't EP coatings be enough since they seem to the same thing only better?
Also, there is only so much surface area on any given metal surface, so do these compounds compete for space? When you add polar esters to the mix, this question seems to become even more complicated. Will the esters "stick" to the surface through all the ablative layers that have been built up? Add in corrosion inhibitors and the complexity factor goes up yet again.
Metal surfaces of course are not smooth at the microscopic level. What effect does this have on the ablative coatings? The main page on this board shows that moly has somewhat of a "filler" property to even out the asperities on the metal surface (which should increase base oil film strength), does that mean that AW coating are only effective at the "peaks" of the asperities?
Lots of questions I know, but after months of reading this board and elsewhere, I have not found answers to these questions. Any insight by people "in the know" would be appreciated.
