Self-healing of a pre-notched WS2/a-C coating

Abstract

This letter reports that a pre-notched WS2/a-C tribocoating surface can be fully healed through sliding. The healed notches act as superior lubricant micro-reservoirs affording frictionless responses leading to an ultralow coefficient of friction (0.02). HR-TEM observations reveal WS2 (002) platelets in the healed notch parallel to the outer coating surface and to the V-notch/coating interface. Direct evidence of the rearrangement of WS2 at the curved interface elucidates that basal plane reorientation does not occur necessarily parallel to the counterpart sliding direction as was taken for granted in literature. The patchy tribofilm provides a new avenue for self-healing efficiency in tribology.

Keywords

• Self-healing
• WS2
• basal plane reorientation
• tribocoating
• HR-TEM