Dry vacuum pump and manufacturing method

A dry vacuum pump comprising:

• a stator and two rotors that are accommodated in at least one compression chamber of the stator, the rotors being configured to rotate synchronously in opposite directions so as to drive a gas to be pumped between an intake and a delivery of the vacuum pump,
• wherein the rotors and the compression chamber of the stator are coated with a nickel-phosphorus coating comprising between 9% and 14% phosphorus and having a thickness greater than 20 μm, the nickel-phosphorus coating having undergone a hardening heat treatment comprising a step of heating to a treatment temperature greater than 250° C. for a treatment duration greater than one hour, so as to have a hardness greater than 700 HV.

A method for manufacturing a dry vacuum pump, comprising:

• depositing a nickel-phosphorus coating comprising between 9% and 14% phosphorus and having a thickness greater than 20 μm on an internal wall of a stator and on walls of rotors of the dry vacuum pump, and
• heat treating the nickel-phosphorus coating of the stator and of the rotors by heating to a treatment temperature greater than 250° C. for a treatment duration greater than one hour, so as to have a hardness greater than 700 HV.