Development of a new molecular dynamics method for tribochemical reaction and its application to formation dynamics of MoS2 tribofilm

Recently we have developed a novel molecular dynamics program NEW-RYUDO-CR, which can deal with chemical reactions. The developed method has been applied to the study of tribochemical reaction dynamics of MoS2 tribofilm on iron surface. The initially amorphous MoS2 layer self-organized its structure as result of the tribochemical reactions and formed layered MoS2 tribofilm. The friction coefficient significantly decreased as the MoS2 tribofilm was formed. Besides, sliding was observed between sulfur layers of MoS2 tribofilms which occurred due to repulsive Coulombic interaction forces between sulfur atoms. This indicates that the formation of the layered MoS2 tribofilm is important to achieve better lubrication properties.