A dry vacuum pump has a stator (2) and two rotors (5) that are accommodated in at least one compression chamber (3) of the stator (2), the rotors (5) 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. The rotors (5) and the compression chamber (3) of the stator (2) are coated with a nickel-phosphorus coating (11) comprising between 9% and 14% phosphorus and having a thickness greater than 20 μm, the nickel-phosphorus coating (11) 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 scroll compressor is provided that may include a casing having a sealed inner space; a drive motor provided in the inner space of the casing to generate a rotational force; a rotational shaft rotatably coupled to the drive motor; an orbiting scroll formed of an aluminum material, and coupled to the rotational shaft to perform an orbiting movement; a fixed scroll coupled to the orbiting scroll to form a compression space; and an Oldham ring coupled to the orbiting scroll, and formed of a sintered metal. With this structure, it may be possible to prevent the Oldham ring from being worn out due to contact with the orbiting scroll. Further, a weight loss portion or wear-resistant coating layer may be formed on a portion of the Oldham ring, thereby suppressing or preventing vibration noise of the scroll compressor from being increased due to a weight increase of the Oldham ring.

A pump for an oil and gas well includes a barrel with a surface configured to contact oil and gas well fluid. The pump further includes a first coating formed on at least a portion of the barrel surface. The first coating includes a combination of diamond particles and a composition including nickel and phosphorous. The pump also includes a plunger with a surface configured to contact oil and gas well fluid. The pump additionally includes a second coating formed on at least a portion of the plunger surface. The second coating includes a combination of tungsten carbide particles and a composition including cobalt and chromium.

A pump for an oil and gas well includes a barrel with a surface configured to contact oil and gas well fluid. The pump further includes a first coating formed on at least a portion of the barrel surface. The first coating includes a combination of diamond particles and a composition including nickel and phosphorous. The pump also includes a plunger with a surface configured to contact oil and gas well fluid. The pump additionally includes a second coating formed on at least a portion of the plunger surface. The second coating includes a combination of tungsten carbide particles and a composition including cobalt and chromium.

A scroll compressor is provided that may include a casing having a sealed inner space; a drive motor provided in the inner space of the casing to generate a rotational force; a rotational shaft rotatably coupled to the drive motor; an orbiting scroll formed of an aluminum material, and coupled to the rotational shaft to perform an orbiting movement; a fixed scroll coupled to the orbiting scroll to form a compression space; and an Oldham ring coupled to the orbiting scroll, and formed of a sintered metal. With this structure, it may be possible to prevent the Oldham ring from being worn out due to contact with the orbiting scroll. Further, a weight loss portion or wear-resistant coating layer may be formed on a portion of the Oldham ring, thereby suppressing or preventing vibration noise of the scroll compressor from being increased due to a weight increase of the Oldham ring.