The effect of the nitrogen-saturating component of the electrolyte on the properties of coatings obtained by anodic plasma electrolyte nitriding

The effect of the nitrogen-saturating component of the electrolyte on the properties of coatings obtained by anodic electrolyte-plasma nitriding of M1044 steel was studied. In this process, ammonia or ammonium nitrate used as a nitrogen donor and ammonium chloride is a component to increase the conductivity of the electrolyte. Treatment duration 5 minutes at temperature range 750–850°С. Corrosion resistance of the coatings obtained from electrolyte with saturating component ammonium nitrate better than coatings from electrolyte with ammonia, аnd it is much less than the raw sample. Wear test (10 N normal load, 0.4 m/s sliding speed, and 240 m sliding distance, Al2O3 ball (6.35 mm in diameter) as counter-body) shows that wear resistance of the sample from electrolyte with saturating component ammonia better than from electrolyte with ammonium nitrate, and significantly less than raw M1044 steel

Possibility of increasing wear resistance of steel by combining anodic plasma electrolytic treatment

The opportunity of enhancement of the wear resistance of steel by combining anodic plasma electrolytic saturation of steel with interstitial elements followed by, quenching and plasma electrolytic polishing was shown. The samples of low-carbon steel were subjected to plasma electrolytic nitrocarburising. The samples of medium carbon steel were subjected to plasma electrolytic boriding. The formation of the modified layer including a hardened diffusion layer and a surface oxide layer occurs as a result of diffusion saturation. After nitrocarburising and boriding the steel samples were polished in an aqueous solution of ammonium sulphate. Conducting the surface polishing results in the removal of a loose part of the oxide layer (predominantly FeO), which reduces the surface roughness more than a half. Wear testing reveals that wear resistance of steel samples after polishing is higher than nitrocarburising ones of 1.8 times and boriding ones of 21.5 times

Increasing wear resistance of Ti6Al4V alloy by anodic saturation with carbon and nitrogen

In this paper, anodic plasma electrolytic nitrocarburising (PEN/C) was applied to Ti6Al4V alloy. This treatment was carried out in electrolyte containing ammonia (5 wt.%), acetone (5 wt.%) and ammonium chloride (10 wt.%) during 5 min at treatment temperature from 750 to 900°C. There were investigated the alloy microhardness, surface roughness and wear resistance. It was shown that the PEN/C results in saturation of studied alloy with oxygen, nitrogen and carbon include formation TiO2 with rutile structure and solid solution in titanium of nitrogen and carbon. This structure provides an increase in microhardness of the surface layer up to 940 HV by sealing the crystal lattice. Surface roughness Ra of treated samples decreases by 1.2–1.4 times and wear resistance increases by 9–10 times after PEN/C. Friction coefficient of PEN/C samples was reduced by 1.5-fold after treatment at 750°C