METHOD OF ION-PLASMA NITRIDING OF ARTICLES FROM TITANIUM OR TITANIUM ALLOY Russian patent published in 2019 - IPC C23C8/36 C23C14/24 

FIELD: technological processes.

SUBSTANCE: invention relates to surface hardening of articles from titanium and titanium alloys by ion-plasma nitriding and can be used in aerospace engineering, machine building, medicine and other branches. Nitrogen or nitrogen-containing mixture of gases is fed into vacuum chamber, electrons are injected into working chamber, glow discharge is ignited between hollow cathode and anode and plasma is generated. Strain is subjected to negative voltage relative to the anode, then the surface of the articles is cleaned and heated by ion bombardment with positively charged ions and subsequent nitration in plasma of the glow discharge. Generation of plasma is carried out in frequency-pulse glow discharge at pulse repetition frequency of 1 Hz 100 kHz with duty cycle of discharge current pulses of 10–90 % at pressure of 0.1–10 Pa. Product is nitrated at average ion current density from plasma of 1–15 mA/cm² and at pulse current density of ions 5–100 mA/cm² in a heated state at a temperature which enables diffusion of nitrogen into the titanium or titanium-containing alloy. In particular case of invention implementation, electrons injection into working chamber volume is performed in pulse mode, wherein electron current pulses are synchronized with glow discharge current pulses, hollow cathode used is inner walls of vacuum chamber or surface of heat shield.

EFFECT: higher saturating capacity of medium for nitriding and hardening of surface of articles.

3 cl, 3 dwg, 2 tbl, 1 ex