METHOD OF FORMING SUPERHARD AMORPHOUS CARBON COATING IN VACUUM Russian patent published in 2004 - IPC

FIELD: protective coatings.

SUBSTANCE: objective of invention is to form superhard wear-resistant coatings in vacuum when manufacturing cutting, shaping, and measuring instruments, parts of friction units, and precision engineering parts. Object is placed in vacuum chamber and, after evacuation, surface of object is exposed to accelerated ions. Treated surface is covered with a layer of material providing adhesion for subsequent layers. Pulse electric-arc discharge is then initiated on graphite electrode to produce pulse stream of carbon plasma from multitude cathode spots, which move across the cathode surface, and carbon plasma is condensed in desired region on the surface of object to form superhard amorphous carbon coating. Temperature of object is meanwhile maintained within a range of 200 to 450^оС by controlling the electric-arc discharge pulse frequency. Carbon plasma pulse stream utilized is characterized by average ion energy 25-35 ev and ion concentration 10¹²-10¹³ cm^-3. Axis of carbon plasma stream is placed at an angle 15-45^о to predetermined surface of object. During coating operation, temperature variation of object lies within the range 50-100K.

EFFECT: eliminated appearance of high internal compression tensions resulting in twisting of substrate and detachment of coating when reaches a certain thickness.

8 cl, 4 ex