Pump with plunger having tribological coating

A method of forming a pump, the method comprising:

• providing a plunger;
• applying a coating to the plunger, wherein applying the coating includes:
• applying a main layer of the coating to the plunger, the main layer containing a tribological material;
• and
• applying a sacrificial break-in layer of the coating to the main layer, the break-in layer containing a tribological material;
• and
• slidably disposing the plunger within a bore, the bore being located in a barrel.

A pump comprising:

• at least one pumping mechanism configured to be fluidly connected to a source of cryogenic fluid, the at least one pumping mechanism including:
• a barrel formed of stainless steel, the barrel including a bore, the bore having a nickel-plated surface;
• and
• a plunger formed of stainless steel, the plunger being slidably disposed within the bore in the barrel, wherein the at least one pumping mechanism is configured to pressurize the cryogenic fluid between the plunger and the barrel;
• and
• a coaling disposed on the plunger, the coating including:
• a support layer containing a diamond-like carbon (DLC) material;
• a main layer disposed on the support layer, the main layer containing amorphous diamond-like carbon (ADLC);
• and
• a sacrificial break-in layer disposed on the main layer, the break-in layer containing a DLC material.