METHOD FOR HIGH DENSITY PLASMA NITRIDNG Russian patent published in 2017 - IPC C23C8/36 C23C8/24 

FIELD: chemistry.

SUBSTANCE: invention relates to thermochemical plasma-assisted treatment of surfaces and is applicable in building of aircraft engine components subjected to cyclic stress to improve engine performance. It also enhances nitriding reaction. The nitriding of titanium alloy surfaces using a plasma glow discharge as a medium for the reaction involves vacuum heating of the titanium alloy parts in high density nitrogen plasma, where the high density nitrogen plasma is formed in the presence of crossed electric and magnetic fields. The nitriding reaction proceeds in N₂ 15% + Ar 85% mix at a pressure of 80 Pa and temperature of 500÷550°C within 1.5÷2 hours with a further replacement of gas mix by N₂ 60% + Ar 40% at a pressure of 40 Pa, exposure time - 1 hour. The reaction is followed by post treatment vacuum cooling of the parts.

EFFECT: invention is an enhanced nitriding process involving formation of an effective nitride diffusion coating on titanium alloys requiring resistance to wear and erosion/corrosion while maintaining their mechanical properties and cyclic fatigue strength.

1 dwg, 1 ex