<p>One of the most important hardening methods of tool steel is the use of carbide coatings, in which during this process, vanadium diffuses in the specimen’s surface and reacts with carbon. During the Plasma Electrolytic Saturation Process, the vanadium element diffuses with the help of plasma and increases up to around 1000 degrees as a result of the temperature, providing conditions for the creation of vanadium carbide. On the other hand, the TRD method during which the specimen is placed inside a salt bath containing the vanadium for a long period of time and the vanadium carbide coating is formed. In this paper, an attempt is made to study the formed coating with the method of plasma electrolytic saturation in addition to comparing the coatings formed by these two methods and obtain some results like: vanadium carbide that created with TRD is purer than PES but that is thinner than plasma method, hardness of coating that created with TRD is about 2500vikers but in TRD is 1100vikers finally. In some PES samples the temperature increase slowly and the maximum temperature is about 120^oC, in this condition, coating is non diffusion. Hardness of PES coating is about 1100vikers so we can use that in industrial molds.</p>

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.

In this study, an Al 2 O 3 /MoS 2 nanocomposite coating was created on an aluminum 1050 substrate using the plasma electrolytic oxidation method. The zeta potential measurements showed that small MoS 2 particles have negative potential and move toward the anode electrode. The nanoparticles of MoS 2 were found to have a zeta potential of −25 mV, which prevents suspension in the solution. Thus, to produce an Al 2 O 3 /MoS 2 nanocomposite, one has to use the microparticles of MoS 2 . The X-ray diffraction analyses showed that the produced coatings contained α-Al 2 O 3 , γ-Al 2 O 3 , and MoS 2 , and that the size of MoS 2 particles can be reduced to 30 nm. It was observed that prolonged suspension in the electrolyte results in an enhanced formation of an Al 2 O 3 /MoS 2 nanocomposite. Using the results, it was hypothesized that the mechanism of the formation of the Al 2 O 3 /MoS 2 nanocomposite coating on the aluminum 1050 substrate is based on electrical energy discharge.

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