Piston including a composite layer applied to a metal substrate

A piston, comprising:

• a body portion formed of metal;
• a composite layer applied to said body portion and forming at least a portion of a combustion surface;
• said composite layer having a thickness of greater than 500 microns;
• said composite layer including a thermoset resin, an insulating component, strengthening fibers, and an impact toughening additive;
• wherein said thermoset resin is a phenolic resin, said insulating component is ceramic, said strengthening fibers are graphite, and said impact toughening additive is an aramid pulp of fibrillated chopped synthetic fibers.

A piston, comprising:

• a body portion formed of metal;
• a composite layer applied to said body portion and forming at least a portion of a combustion surface;
• said composite layer having a thickness of greater than 500 microns;
• said composite layer including a thermoset resin, an insulating component, strengthening fibers, and an impact toughening additive;
• wherein said metal of said body portion is aluminum or steel;
• said body portion includes a crown extending circumferentially about a center axis from an upper end toward a lower end;
• said crown presents an uppermost surface at said upper end;
• said uppermost surface includes a combustion bowl extending inwardly and downwardly from a planar outer rim;
• said uppermost surface includes an undercut scroll thread;
• said composite layer is disposed on said undercut scroll thread of said uppermost surface;
• said composite layer has a thermal conductivity of 0.8 to 5 W/m·K;
• said thermoset resin is a phenolic resin, said insulating component is a ceramic, said strengthening fibers are graphite, and said impact toughening additive is an aramid pulp of fibrillated chopped synthetic fibers;
• said thermoset resin is present in an amount of 25 wt. % to 35 wt. %, based on the total weight of said composite layer;
• said insulating component is present in an amount of 50 wt. % to 70 wt. %, based on the total weight of said composite layer;
• said strengthening fibers are present in an amount of 1 wt. % to 10 wt. %, based on the total weight of said composite layer;
• and said impact toughening additive is present in an amount of 1 wt. % to 10 wt. %, based on the total weight of said composite layer;
• and
• said composite layer has a thickness of 2 millimeters to 3 millimeters.