Fig 1.
Molecular structures of organic molybdenum given by the suppliers.
(a) molybdenum dithiocarbamate (MoDTC), (b) molybdenum amide (MA), and (c) Molybdenum dialkyldithiophosphate (MoDDP).
Table 1.
Base oil and additive abbreviations.
Table 2.
Test oil formulations.
Fig 2.
The ring and block of test specimens.
Fig 3.
Schematic of test rig.
Fig 4.
Photos of test rig.
Fig 5.
The base oil viscosity in different test temperature.
Table 3.
The friction test conditions.
Fig 6.
Shows the friction coefficient of test lubricant containing MoDTC and organic friction modifiers during 6 hours test, test temperature 40°C.
Fig 7.
Influence of organic friction modifiers to the friction coefficient of organic molybdenum, (a) MoDTC and organic friction modifiers, (b) MA and organic friction modifiers, (c) MoDDP and organic friction modifiers.
Fig 8.
Optical images of block wear surface.
Fig 9.
Wear scar width of block lubricated with different test oil formulas at 150°C.
Fig 10.
SEM image of wear surface.
Fig 11.
EDS of friction surfaces (a) MoDTC (MC) containing lubricants, (b) molybdenum amide (MA) containing lubricants, (c) MoDDP (MP) containing lubricants, (d) Base oil (BO).
Fig 12.
Friction surface XPS photopeaks of Mo3d lubricated with MoDTC (MC) containing lubricants.
Fig 13.
Friction surface XPS photopeaks of Mo3d lubricated with Molybdenum Amide (MA) containing lubricants.
Fig 14.
The XPS photopeaks of Mo3d lubricated with MoDDP (MP) containing lubricants.