Surface Hardening of Machine Parts Using Nitriding and TiN Coating Deposition in Glow Discharge

Alexander Metel,Yury Melnik,Marina Volosova,Enver Mustafaev,Sergey Grigoriev

doi:10.3390/machines8030042

Alexander Metel, Yury Melnik + Show 3 more

Open Access

https://doi.org/10.3390/machines8030042

Copy DOI

Abstract

Surface hardening of machine parts substantially improves their performance. The best results are obtained when combined hardening consists of surface nitriding and subsequent deposition of hard coatings. The nitriding of machine parts immersed in the plasma of glow coatings have been studied, and the study results are presented. Titanium atoms for coating synthesis are obtained via titanium evaporation in a hollow molybdenum anode of the discharge. Stable evaporation of titanium occurs only when the power density of electrons heating the liquid titanium does not exceed ~500 W/cm2. To start evaporation, it is only necessary to reduce the gas pressure to 0.02 Pa. To stop evaporation, it is enough to increase the gas pressure to 0.1 Pa. Fast argon and nitrogen atoms used for cleaning the machine parts, heating them, and bombarding the growing coating are obtained using a grid composed of plane-parallel plates under high negative voltage and immersed in plasma.

Highlights

Ion-plasma processing of engineering products allows purposeful modification of their surface properties
When an anode disk with a diameter of 15 cm is installed in the chamber, the effective area of the anode is equal to Sa ≈ 320 cm2
With the anode disk diameter of 11 cm, the anode area is equal to Sa ≈ 160 cm2, and the cathode fall Uc begins to increase with decreasing pressure at po 2 = 0.09 Pa

Summary

Introduction

Ion-plasma processing of engineering products allows purposeful modification of their surface properties. Ion-plasma treatment reduces the coefficient of friction, increases the useful life of the products, and significantly increases their wear resistance and corrosion resistance. It allows for combined treatment; for example, ion nitriding of steel products with the subsequent deposition of wear-resistant coatings [5]. In the latter case, a hardened surface layer with a thickness of 50–100 μm prevents brittle fracture of hard coatings with thickness not exceeding 5 μm. The product combines wear resistance with high load-bearing capacity and good fatigue strength

Methods

Results

Discussion

Conclusion