PISTON ASSEMBLY HAVING ABRADABLE COATING

摘要

A piston assembly operable within a fluid bathed cylinder wall, comprising a piston body (10) having at least one annular land (36) adapted to be in close-fitting relationship to the cylinder wall (37) an abradable coating (15) tenaciously adhered to said at least the one land (36) effective to create and sustain substantially zero clearance with the fluid bathed cylinder wall and a heat sink in the form of at least one of (i) heat conductors (23) in the coating to conduct heat from the land (36) and (ii) a piston body interior (52) effective to receive a heat conducting fluid (26) moving along the interior to extract heat therefrom. The abradable coating comprises solid lubricants at least two of which are selected from the group consisting of graphite, molydisulphide and boron nitride The heat conductors in the coating preferably consist of copper particles distributed throughout the coating and constitute at least 70-90% by weight of the abradable coating.