One of the most important hardening methods of tool steel is the use of carbide coatings. During this process, vanadium atoms diffuse the specimen’s surface at high temperature and reacts with the available carbon in steel and create vanadium carbide with high hardness. During the plasma electrolytic saturation (PES) process, the vanadium element diffuses with the help of plasma and increases up to around 950[Formula: see text] as a result of the temperature, providing conditions for the creation of vanadium carbide. The best combination of electrolyte is 4[Formula: see text]g vanadium oxide and 50[Formula: see text]mL hydrochloric acid and different concern of sodium hydroxide. The results indicate that the formed coating is about 30[Formula: see text][Formula: see text]m. As the conductivity increases, the condition for diffusion is provided; however, with increase in the temperature, the diffusion decreases. The coating formation is observed in the current at 9–11 A and hardness of this coating is about 1400[Formula: see text]vickers.

One of the most important methods of hardening steel tools is nitriding. During this process, nitrogen diffuses into the sample surface at high temperature and reacts with the elements existing in the sample and creates hard nitrides. Another way to create hard nitrides is the simultaneous hard diffusion of two nitride-causing elements. During the plasma electrolytic saturation process, one nitride -causing element, together with nitrogen, diffuses into the surface of the sample and forms a hard nitride coating on the surface of the component. In this process, a voltage is applied between a cathode (sample with smaller surface) and an anode (sample with larger surface); the plasma is formed on the surface of the cathode which then let the given elements diffuse into the surface of the base metal. In the present study, nitrogen and vanadium have diffused into the surface of the sample, 1.2436 tool steel, and vanadium nitride has been formed. The best combination of electrolyte solution is 4g Ferro vanadium, 50±1 ml nitric acid and sodium hydroxide. The results is indicating that the formed coating layer thickness is about 2-3.5 µm. As the conductivity increases, the condition for diffusion is provided; however, with over increasing the temperature, diffusion decreases. The coating formation has observed in 7-10±0.5 A current.Keywords: wear, Vanadium nitride, Steel 1.2436, Plasma electrolytic saturation 1 Introduction Advances in technology and the current intense industrial competitions have forced materials and metallurgical engineers to seek and use cost efficient with maximum efficiency methods. Thus, the significant attention is drawn to the surface metallurgy methods. The surface metallurgy is a suitable method to produce engineering material with hard surface and though matrix. In the modern surface engineering, the method which can enrich requirements as fast and cheap as possible is regarded as a better one. Hard coating is usually used in some working that surface resistant resistance wear should be very high. Vanadium nitride (VN) is one of these hard coats which is using in such cases as molds using in metallurgical processes e.g. casting, forging, extrusion etc. The main old way of VN coating was "molten salt bath method" based on setting whole a sample in a salt bath of ferro vanadium with 900 Celsius degree for 6-10 hours. This means a lot of wasted time and energy in industrial scale; besides thermal stress will be very high in the sample bulk. In the new method of VN coating called "plasma electrolysis method", only the surface of samples are in touch with high temperature of 900 Celsius degree and also, whole of this process taking just 15 minutes. Hence, the obvious fact is using this method can present better performance and efficiency to the