مجله علوم و مهندسی خوردگی
سال یازدهم شماره 4 (پیاپی 42، زمستان 1400)

In this research, nanocomposite coatings based on zinc oxide and homopolymers of aniline, anisidine, toluidine and aminophenol were prepared by electrophoresis on the surface of 304 stainless steel and their corrosion resistance was studied while characterizing the coatings. Polymerization took place in an acidic medium using ammonium persulfate as the oxidizing agent. The nanocomposites were characterized using FTIR, XRD and SEM techniques. The corrosion behavior of the coating in 3.5 wt% sodium chloride solution was evaluated by dynamic dynamic methods at ambient temperature. The results showed that the conductive nanocomposite as a coating reduces the rate and intensity of corrosion flow. The anti-corrosion effect of each polymer depends on the extraction group on the benzene ring and with increasing the lethality of each extraction group, the anti-corrosion effect of the polymer decreases.

The grate plates are one of the pertaining components of the grate machine in the iron ore pellet industry, which is made up of heat-resistant stainless steel. The work life of these grate plates affects the production rate and quality of the pellets. The purpose of this study was to investigate the cause of this steel sensitization and the effect of elements on its lifetime. To do this, the lattice plates used in Zarand steel pellet factory were used to build these steel plates which are 1.4837 DIN steel. Samples were examined by electron microscopy, X-ray diffraction test and polarization test. The results indicated that there is no depletion chromium in this steel, but the steel carbide's crack cause the sensitivity of steel to intergranular corrosion.

Anti-corrosion coatings based on the epoxy resin belnding with different extenders including talc, silicon dioxide and barium sulfate were prepared and applied on the carbon steel surface. The corrosion behavior of these coating systems versus the immersion time in 1M sulfuric acid was investigated by using electrochemical impedance spectroscopy (EIS) method. The anti-corrosion behavior of the coatings was simulated using EIS data and the approperiate equivalent circuit models. Variation of the coating and double layer parameters showed that the protective strenght of the epoxy coating blending with different extenders against corrosion is as the following sequence: Talc > Silicon dioxide > without extender > Barium sulfate

Only a limited amount of water on the earth is suitable for domestic, industrial, or agricultural applications. Accordingly, seawater must be treated and turned into freshwater to meet the need of the growing population. The desalination process is conducted in industrial plants. One of the most significant causes of failures in desalination plants is the phenomenon of corrosion which occurs in different forms, particularly in the form of localized corrosion. Two main reasons for such corrosion failures are the high sodium chloride concentration in seawater and the incorrect design of different components. Unanticipated corrosion may contribute to unexpected stops, resulting in lower productivity and more importantly, loss of life. Thus, corrosion control technology will reduce emergency stops and increase efficiency. It is achievable to prevent future failures in this industry by analyzing previous failures, their origins, and prevention methods. Therefore, these subjects have been discussed in this paper, and some case studies have been reviewed.

The study of superfluid levels due to the importance of these levels in many applications has been considered. In this study, nickel-copper alloy coatings were created using a two-step electrochemical deposition method-the surface energy reduction and microstructure and corrosion resistance were investigated. Surface morphology was investigated using scanning electron microscopy and XRD for field publishing and fuzzy structure. Corrosion resistance was investigated using potentiodynamic polarization method as well as electrochemical impedance spectroscopy. The results of this study showed that by increasing the concentration of Modidium crystal in the coating bath, the nanostructured coating was obtained and at a concentration of 200 grams per liter, a hieratic hierarchy coating was obtained. XRD data showed that only the nickel phase was created and a solid solution was created by the entry of copper atoms into the structure. Corrosion behavior studies showed that with the formation of coating, the corrosion density decreased from 6.2 to 0.12 mA/cm2 , and corrosion potential from-273 to -171 also decreased. The reason for this was the capture of trapped air in the coating, thereby preventing the entry of corrosive ions into the substrate as well as the Laplace pressure.

In this study, the effect of input heat of SMAW process on the microstructure and corrosion behavior of welded metal API 5L X65 steel joints coated with INCOLOY 825 superalloy was investigated. Welding with input heat of 1.03, 0.99 and 0.94 kJ / mm was performed using E7018 filler metal by SMAW process. FESEM scanning light and electron microscopy was used to study the microstructure. Evaluation of corrosion behavior of weld metal was performed using TOEFL polarization test in 3.5% NaCl solution. The microstructural results showed that the needle ferrite in the weld metal microstructure decreased with increasing inlet heat. While the values of Wiedmann Statten ferrites are multifaceted and grain boundaries. It was found that increasing the inlet heat had a negative effect and reduced the corrosion resistance of the weld metal.