ION-PLASMA PRECISION NITRIDING OF METAL PART SURFACE Russian patent published in 2015 - IPC C23C14/48 C23C8/36 

FIELD: process engineering.

SUBSTANCE: invention relates to plasma chemical-thermal treatment, particularly, to method of ion-plasma nitriding and can be used in machine building, engine production, metallurgy, etc. Argon-based gas-discharge plasma is preliminary initiated. After holding of nitrogen in argon-base initiated plasma it is fed into gas-discharge plasma to feed a negative shift potential to processed article at smooth variation to working magnitude and to perform the isothermal curing. Thereafter, argon-nitrogen mix is replaced with pure nitrogen to create the plasma flux containing the nitrogen ions, to up the shift negative potential and to perform the isothermal curing in nitrogen plasma.

EFFECT: nitride-hardened ply is formed at article surface with stable-equilibrium microstructure with no fragile surface structure, higher hardness, no warpage, accelerated nitriding (some 3-5 times).

6 cl, 2 tbl, 4 ex, 6 dwg