Abstract <p>Electrical discharge machining of molybdenum surfaces used to increase hardness, heat resistance, and corrosion resistance of machine parts, units, and assemblies has been studied. It has been found that electrical discharge machining of molybdenum surfaces allows obtaining durable functional coatings of parts by using a high-voltage electric arc in a hydrogen atmosphere at a pressure of 0.1 MPa and a fixed gap between anode made of graphite and the processed surface of the part, cathode, at a rigid current–voltage characteristic of a pulsed current source with a voltage of 2000 V. The pulse duty cycle has been varied depending on required roughness of the molybdenum carbide Mo₂C coating. Depending on the supplied power two carbide phases in different percentage ratio α-Mo₂C : β-Mo₂C were formed on the surface.</p>