Corrosion Resistance Of Cast Iron Research Articles

Effect of a surface treatment consisting of electron beam remelting and gas nitriding on the corrosion resistance of cast iron

AbstractCommercially available gray‐solidified cast iron exhibits reduced load‐carrying capacity under locally concentrated pressure with simultaneous sliding stress. Electron beam remelting dissolves the graphite near the surface, and the surface layer solidifies according to the metastable system. During subsequent gas nitriding, a dense compound layer forms on this white‐solidified, hard surface layer. The phase composition of the compound layer depends not only on the gas nitriding conditions, but also on the chemical composition of the cast iron. The effect of the individual processes of remelting and gas nitriding and their combination on the corrosion behavior of one ferritic and one pearlitic cast iron with different copper contents is investigated using potentiodynamic polarization measurements in 5% sodium chloride solution at room temperature. The remelted and nitrided surface layers exhibit the highest corrosion resistance. The proportion of iron carbonitrides γ' and ε contained in the compound layer influences the corrosion behavior.

On a possibility of replacing grey cast iron for manufacturing cast elements of electrolyzer gas collecting bell

The main process leading to the destruction of the cast elements of gas-collection bell of electrolyzer, made of grey cast iron, is the oxidation of iron by oxygen, SO2 gas and sulfur vapors to form magnetite, hematite and pyrrhotin. The simultaneous formation of iron oxides and sulfides does not prevent further corrosion, since scale is formed with a loose structure that does not have protective properties. Reducing the length of the interfacial boundaries inside the material of the cast enables to reduce the rate of corrosion destruction, which can be achieved by modifying the cast iron to change the shape of graphite inclusions, i.e. obtaining high-strength cast iron with a spherical shape of graphite inclusions. However, the obtaining spherical graphite in cast iron using magnesium modification does not exclude the access of aggressive gases to the surface of the products and the possibility of their diffusion along the grain boundaries. It was shown that alloying can be an alternative, which leads not only to the exclusion of lamellar secretions of graphite in the structure of cast iron, but also to the formation of surface oxide layers based on the alloying element preventing the corrosion. Alloying with chromium gives cast iron high abrasive resistance due to the presence of a carbide component in the structure, as well as corrosion resistance due to the alloying of the metal base, heat resistance due to increasing the electrochemical potential of the metal base and creating a strong neutral oxide film on the surface of the castings, heat resistance, etc. An experimental comparative analysis of the corrosion resistance of cast iron used for manufacturing of gas collecting bell of electrolyzers showed that chromic cast iron ЧХ3 has a higher corrosion resistance than high-strength cast iron with spherical graphite ВЧ50 and much higher than grey cast iron with lamellar graphite. However, chromic cast iron ЧХ3 has low casting properties, is very sensitive to the cooling rate and has a large heterogeneity in structure, which makes it difficult to use it for the manufacture of gas collecting bell of electrolyzers.

Evaluation of Corrosion Behavior of Different Grades of Cast Iron Insodium Chloride Solutions

In this work, the corrosion behavior of different grades of cast iron in 3.5% and 5% of NaClsolution was evaluated. The samples used in this work are; Grey cast iron (GI), ductile cast iron(DI), austempered ductile cast iron (ADI), intercritically austempered cast iron (IADI) and Ni-Resist cast iron. The study was carried out using the Open- Circuit technique (OPC),Potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS)measurements and complemented by Scanning electron microscopy (SEM) and Energydispersive X-ray analysis (EDAX). The results obtained showed that the austempering heattreatment and nickel addition improves the corrosion resistance of cast iron. The order ofcorrosion resistance in NaCl solution is as follows: Ni-Resist > ADI > IADI > DI > GI.

Corrosion resistance study of grey cast iron implanted with C, N, Cr and Cu ions

This article deals with the corrosion resistance of gray cast iron implanted with C, N, Cr and Cu ions in sodium chloride solution and sulfuric acid solution. The potentiodynamic research was conducted in atmosphere, simulating corrosion conditions: in 3% sodium chloride solution and in 0,1 N sulfuric acid solution. Potentiodynamic curves were obtained and surfaces of samples were observed. The research proves that the implantation of ions with N and Cr leads to an increase in the corrosion resistance of cast iron in sodium chloride solution, and the implantation of ions with N and Cu leads to increased corrosion resistance in sulfuric acid solution.

Preparation and Characterization of Thiosemicarbazones Corrosion Inhibition Effect and the Antimicrobial and Anticancer Effect on their Metal Complexes

Benzofurane and naphthofuranethiosemicarbazone ligands 2a (L1 )and 2b(L2) and their Cu(II), Co(II), Ni(II), and Pd(II) complexes have been synthesized and characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, IR, NMR, and electronic spectral studies. IR spectra show that the ligands is coordinated to the metal ions in a didentate manner with N,S doner sites. In the presence of tow thiosemicarbazones ligands 2a(L1) and 2b(L2), the corrosion resistance of cast iron in 10.M H2SO4 increases in the order, 2b(L2) >2a(L1). The effect of studied ligands inhibits the corrosion of cast iron extent depending on the structure and high donation of π-electron present inhibitor. Co(II) and Pd (II) complexes possess higher antimicrobial activity than free ligands and other complexes. The [L1Pd Cl2]H2O complexe shows higher IC50 value of 4.6 µg/ml toward human breast cancer cell lines (MCF-7). For other complexes, they are in the range of 2.7– 4.3 µg/ml toward the former cells which is related to their metal complexing ability in enzymes.

Effect of Organic Polymer Plating on Corrosion Resistance of Cast Iron

Effect of Organic Polymer Plating on Corrosion Resistance of Cast Iron

Microstructure and Corrosion Performance of Carbonitriding Layers on Cast Iron by Plasma Electrolytic Carbonitriding

The surface carbonitriding of cast iron is investigated in an aqueous solution of acetamide and glycerin. Microstructure, chemical and phase composition and corrosion performance of the carbonitriding layers are investigated by scanning electron microscopy, energy dispersive spectroscopy and x-ray diffraction, as well as potentiodynamic polarization testing. X-ray diffraction results show that the carbonitriding coatings are composed of martensite, austenite(γ-Fe), Fe2C, Fe3C, Fe5C2, FeN and ∊-Fe2−3N. After the plasma electrolytic carbonitriding treatment the corrosion resistance of cast iron is clearly improved compared to the substrate, and the coatings produced at 350 V for 30s give the best corrosion resistance.

Corrosion Behaviour of Borided and Nitrided Steels in Aqueous Media

Case hardening may result in a considerable extension of the life of machine parts subjected to the simultaneous action of wear and aqueous corrosion, provided that the resistance of the hardened surfaces against corrosion attack is at least equal or superior to that of the base material. The present work is devoted to the effect of boriding and nitriding on the corrosion resistance of cast iron, mild steel and some stainless steels under different environmental conditions.The results from electrochemical and conventional corrosion tests show that corrosion rates of nonalloyed iron-based materials, depending on the nature of the corrosive environment, are either decreased or not significantly influenced by boriding or nitriding. However, both nitriding and boriding may lead to a loss of corrosion resistance of stainless steels.

鋳鉄の耐アルカリ性に就て

The authers have carried out the corrosion test of cast iron in the molten bath of sodium hydroxide. Influence of several alloying elements on the corrosion resistance of cast iron was studied. Silicon is the most important element; because the corrosion resistance of cast iron is markedly decreased with the increasing amount of silicon. Nickel, copper and aluminium increase the corrosion resistance. For the use of these elements, however, care must be taken to keep the silicon content of the cast iron lower; otherwise the corrosion resistance may be worse. Chromium and sulpher have the tendency to increase the corrosion resistance Carbon and manganese have no influence, phosphorus has rather a favorable influence on the corrosion resistance.