|
As fundamental studies
on lubricating oil additives, adsorption and reaction
behaviors of phosphorus type extreme pressure additives
on iron surface have been investigated by a flow
type adsorption test. Initial adsorption rates of
phosphorus-containing esters depended largely on
existence of -OH and P=O bonds in the molecules
. Amount of adsorprion was influenced by the hydrolyzing
property of the esters. Ester bonds of the additives
were found to hydrolyze through the reaction with
the water adsorbed on the iron surface. Phosphite
esters hydrolyzed to inorganic acid regardless of
the esterification degree followed by adsorption
as its iron salt. Adsorption behaviors of the phosphate
esters varied depending on the esterification degree;
triester adsorbed on the iron surface after being
decomposed hydrolytically to monoester, while diester
was adsorbed without hydrolysis. It was suggested
that the adsorbing and hydrolyzing properties of
these ester compounds depended on the configurations
of the molecules physisorbed on the iron surface.
@
|
