Originally Posted By: edhackett
It was actually a very comprehensive thesis. They looked at each major additive individually and a fully formulated oil. They explained the way WS2 works as an anti-wear, anti-friction additive. They showed why WS2 cannot work in a fully formulated oil.
Abbreviated Cliff's Notes:
The IF-WS2 does not work as miniature ball bearings. It works by bonding to the metal and shearing as does graphite and MoS2. The bonding relies on oxidation of the metal and the WS2. The oxidation inhibitors/anti corrosion additives interfere with the oxidation needed for bonding. ZDDP alone and ZDDP+WS2 show nearly identical wear. The fully formulated oil shows a greater wear increase than what you would expect from looking at the individual effects. I suspect that there is a synergy between the anti-oxidants and ZDDP layer preventing the WS2 from bonding to the metal.
They do not go into the cause of the higher wear seen with WS2. They do mention that the IF-WS2 is larger than the gaps it needs to get into to act directly. My theory is that if the WS2 is prevented from bonding to the metal and acting as an anti-wear/anti-friction additive, it acts as abrasive particles.
I don't know of a way to formulate a practical oil without anti-oxidants or corrosion inhibitors, so I don't think WS2 has any use as a motor oil additive.
They also stress several times that a low coefficient of friction does not always correlate with low wear. That's well known.
Ed
Ed thanks so much for this explanation of WS2 as a motor oil additive and the damage it may cause. We have been reading up on and testing some of the nano tech additive claims. After the tear down of a test engine I could see what the hexagonal boron nitride (Liqui Moly Ceratec in this study) did and did not no do to reduce friction by laying down a ceramic like coating.
Where there was heat and pressure the micron thin coating could be detected like crank and cam bearing surfaces but the piston skirts did not show the same but the cylinder walls did where the rings passed.
Just dumping in additives willy nilly into one's motor oil may not be without risks.
It was actually a very comprehensive thesis. They looked at each major additive individually and a fully formulated oil. They explained the way WS2 works as an anti-wear, anti-friction additive. They showed why WS2 cannot work in a fully formulated oil.
Abbreviated Cliff's Notes:
The IF-WS2 does not work as miniature ball bearings. It works by bonding to the metal and shearing as does graphite and MoS2. The bonding relies on oxidation of the metal and the WS2. The oxidation inhibitors/anti corrosion additives interfere with the oxidation needed for bonding. ZDDP alone and ZDDP+WS2 show nearly identical wear. The fully formulated oil shows a greater wear increase than what you would expect from looking at the individual effects. I suspect that there is a synergy between the anti-oxidants and ZDDP layer preventing the WS2 from bonding to the metal.
They do not go into the cause of the higher wear seen with WS2. They do mention that the IF-WS2 is larger than the gaps it needs to get into to act directly. My theory is that if the WS2 is prevented from bonding to the metal and acting as an anti-wear/anti-friction additive, it acts as abrasive particles.
I don't know of a way to formulate a practical oil without anti-oxidants or corrosion inhibitors, so I don't think WS2 has any use as a motor oil additive.
They also stress several times that a low coefficient of friction does not always correlate with low wear. That's well known.
Ed
Ed thanks so much for this explanation of WS2 as a motor oil additive and the damage it may cause. We have been reading up on and testing some of the nano tech additive claims. After the tear down of a test engine I could see what the hexagonal boron nitride (Liqui Moly Ceratec in this study) did and did not no do to reduce friction by laying down a ceramic like coating.
Where there was heat and pressure the micron thin coating could be detected like crank and cam bearing surfaces but the piston skirts did not show the same but the cylinder walls did where the rings passed.
Just dumping in additives willy nilly into one's motor oil may not be without risks.