Slipper component with ceramic surface

A rotary axial piston pump comprising:

• a housing;
• a swash plate, the swash plate having an inclined surface;
• a rotor assembly positioned adjacent the swash plate, the rotor assembly comprising a rotor-drum having at least one cylinder bore disposed therein, and having piston(s) disposed within the respective cylinder bore(s), the pistons having a ball-shaped end extending from the cylinder bore(s);
• at least one slipper interposed between the swash plate and the rotor-drum, the slipper(s) comprising socket joints for accommodating the piston ball-shaped end(s) therein, the slipper(s) having a swash plate interface surface in contact with the swash plate inclined surface;
• a port plate positioned adjacent an end block disposed in the housing open end;
• and
• a valve plate interposed between the port plate and the rotor-drum;
• wherein the swash plate interface surface comprises an annular ceramic ring attached to the slipper, the annular ceramic ring having an axially facing upper surface, a radially outward surface and a radially inward surface, the axially facing upper surface of the annular ceramic ring facing a lower surface of the slipper, the radially inward surface of the annular ceramic ring being positioned about an inner annular wall of the slipper, and a seal positioned between the radially inward surface of the annular ceramic ring and the inner annular wall of the slipper to restrict pressurized fluid from flowing between the lower surface of the slipper and the axially facing upper surface of the annular ceramic ring, the lower surface of the slipper having a weep groove or channel.