Tsakos Energy Navigation Limited
Steel piston crown and/or combustion engine components with dynamic thermal insulation coating and method of making and using such a coating

Abstract:

A piston for an internal combustion engine is provided. The piston includes a thermal barrier coating applied to a crown formed of steel. According to one embodiment, a bond layer of a metal is applied to a combustion surface of the crown, followed by a mixed layer of metal and ceramic with a gradient structure, and then optionally a top layer of metal. The thermal barrier coating can also include a ceramic layer between the mixed layer and top layer, or as the outermost layer. The ceramic includes at least one of ceria, ceria stabilized zirconia, yttria, yttria stabilized zirconia, calcia stabilized zirconia, magnesia stabilized zirconia, and zirconia stabilized by another oxide. The thermal barrier coating is applied by thermal spray, HVOF, or wire arc spraying. The thermal barrier coating preferably has a thickness less than 200 microns and a surface roughness Ra of not greater than 3 microns.