Lubricant composition and method for using the lubricant composition

Abstract

A lubricant composition comprising: a fully formulated commercial lubricating oil which comprises from 0.01 to 2.0 percent by weight of an oil soluble organo-molybdenum friction modifier and at least 0.1 percent by weight active sulfur of a surface active sulfur donor component is effective in preventing the removal of DLC coatings while at the same time allowing the beneficial friction-reducing effects from the molybdenum friction modifier to occur.

1 . A method for improving the wear of surfaces having a diamond-like coating comprising:
 preparing a lubricant composition which comprises 0.01 to 2.0 percent by weight of an organic molybdenum friction modifier and at least 0.1 percent by weight of a surface active sulfur donor component;   lubricating an interface between a first surface and a second surface with the lubricant composition wherein at least one of the first and second surfaces has a diamond-like coating thereon;   wherein no greater than 10% of a thickness of the diamond-like coating is removed following three hours of relative movement between the first and second surfaces under a normal force of 200N, frequency of 20 Hz, temperature of 130° C.   
     
     
         2 . The method according to  claim 1  wherein no more than 10% of the thickness of the diamond-like coating is removed. 
     
     
         3 . The method according to  claim 1  wherein no more than 1% of the thickness of the diamond-like coating is removed. 
     
     
         4 . The method according to  claim 1  wherein the diamond-like coating comprises from 0% to 35% hydrogen concentration. 
     
     
         5 . The method according to  claim 1  wherein the surface active sulfur donor component is selected from the group consisting of aryl sulfides, alkyl sulfides, dimercaptothiodiazole, sulfurized isobutylene, dialkylpentasulphide, and combinations thereof. 
     
     
         6 . A lubricant composition comprising: a fully formulated commercial lubricating oil which comprises from 0.01 to 2.0 percent by weight of an oil soluble organo-molybdenum friction modifier and at least 0.1 percent by weight of a surface active sulfur donor component. 
     
     
         7 . The lubricant composition according to  claim 6  wherein the lubricating oil is selected from the group consisting of synthetic oils, petroleum derived oils, plant derived oils, animal derived oils, and combinations thereof. 
     
     
         8 . The lubricant composition according to  claim 6 , wherein the organic molybdenum friction modifier is selected from the group consisting of molybdenum dithiocarbamate, molybdenum dialkyldithiophosphates, and combinations thereof. 
     
     
         9 . The lubricant composition according to  claim 6 , wherein the surface active sulfur donor is selected from the group consisting of aryl sulfides, alkyl sulfides, dimercaptothiodiazole, sulfurized isobutylene, dialkylpentasulphide, and combinations thereof. 
     
     
         10 . (canceled)