Thermal Analysis and Selected Properties of CuNi2Si Alloy Used for Railway Traction

This paper investigates the effect of high-temperature aging (600 °C and 650 °C) on the microstructure and functional properties of copper CuNi2Si alloy. The paper also presents the results of elastomeric tests performed by means of the Gleeble 3800 heat and plastic treatment simulator, as well as DTA (Differential Thermal Analysis) analysis carried out for the investigated alloy aged for 1, 2, 4 and 7 h. Corrosion resistance tests were performed by means of the potentiodynamic method with Atlas Sollich Atlas 0531 potentiostat/galvanostat in a 3% sodium chloride solution. Based on the tribological tests, it was confirmed that the CuNi2Si alloy was solution heat treated from the temperature of 1000 °C and gradually aged at the temperature of 600 °C and 650 °C for 1–7 h, characterized by a stable wear resistance. The alloy aged at the temperature of 600 °C was characterized by a lower mass loss compared to the one aged at 650 °C. Based on the DTA analysis, it was found that for the alloy aged for 2, 4 and 7 h, at the temperatures of 401 °C, 411 °C and 412 °C, respectively, the decomposition of a supersaturated solid solution took place by spinodal transformation accompanied by a sequence of phase transitions DO22 [(Cu, Ni)3Si],→ δ-Ni2Si → (Cu, Ni)3Si. The results of these investigations have proved that the CuNi2Si alloy can be widely used for electric traction. The use of alloys that replace elements made entirely of copper and, in this way influencing its lower demand, is in line with the global policy of economical management of natural resources.

Evaluation of the Inhibitive Effect of Ibuprofen Drug on the Acidic Corrosion of Aluminium 6063 Alloy

This research examined the corrosion inhibition potency of inhibitive Ibuprofen drug (IID)on aluminium 6063. The effect of the inhibitive drug was tested in 0.5 M of H2SO4 solutionusing potentiodynamic method. The concentration of IID was mixed to the acidic mediumin 0, 5, 10, 15 and 20 ml respectively. The polarization experiment shows IID adsorbed onaluminium specimens. Increase in IID concentration decreases corrosion rate of aluminiumspecimens. Maximum inhibitive efficiency of 80.58 % and further studies on the inhibitoryeffect of the drug inhibitor revealed that Freundlich isotherm displayed a regressioncoefficient value of 0.7893 while Langmuir isotherm exhibits a regression coefficient valueof 0.8864. These values of regression establish the reliability of IID as inhibitor, whichshows that IID can be used as inhibitor corrosion of aluminium in aggressive environmentsuch as marine and petrochemical industries where protection of aluminium is a necessity.

Analysis of Corrosion Breakdown Rate in Low Carbon Steel with Aluminum Coating

This study aims to analyze the corrosion penetration rate of low carbon steel with aluminium coating. The method used is the potentiodynamic method to determine the value of the corrosion rate. The corrosion medium used was HCl. The aluminium used is aluminium frame waste powder. The coating process is by dipping low carbon steel pipes into aluminium frame waste that had been liquefied in the Hot Dip Galvanizing (HDG) method of 700oC and immersion time of 45 seconds. The results of this study show that low carbon steel which has been coated with aluminum frame waste powder has a high corrosion rate which is proven to have a corrosion rate of 18,1808 mm/year. So that the corrosion rate is at an unacceptable level.

In-Situ Spectroelectrochemical Study of Conductive Polyaniline Forms for Sensor Applications

Our contribution focuses on a correlative study of polyaniline (PANI) electropolymerisation and UV/VIS spectroscopy. PANI was prepared via electro-oxidation using a potentiodynamic method on commercial gold screen-printed electrodes (Au-SPE). By using an in-situ spectroelectrochemical method, the development of the polymer was observed from monomer, monomer oxidation to final polymer formation and its transformations between the oxidation forms. The results confirm the spontaneous doping of the polymer during the polymerisation, the instability of leucoemeraldine form in air and its two-stage oxidation to emeraldine form. The final conductive PANI deposited on Au-SPE will be used as sensor element for the detection of toxic organic compounds.

Investigation of color and anticorrosive properties of pigments in the Fe-Al-Mg-O-H system by the simplex lattice method

Purpose The purpose of this paper is to study the patterns of formation of anti-corrosion properties, the development of compositions for pigments by using the method of co-precipitation and subsequent heat treatment. Design/methodology/approach To obtain co-precipitated hydroxides, aqueous solutions of salts were used. The conditions of synthesis varied according to the following parameters: the nature of the starting salts of metals; and the ratio of metal cations. The anticorrosive activity of the pigments was evaluated by the potentiodynamic method, by comparing the anodic and cathodic polarization curves, and calculated potentials and corrosion currents on the basis of regions of Tafel on curves. Polarization curves were obtained by using Potentiostat/Galvanostat/ZRA Gamry, which connected to the PC, and by using the program Gamry Framework. The measurement results were processed by using the method of simplex-lattice planning. X-ray diffractograms of pigments were recorded on a DRON – 2.0 diffractometer (monochromatic copper radiation with a nickel filter). Findings The paper deals with the results of research the dependence of colour characteristics and anticorrosion properties of synthesized compositions on their nature and composition. The presence of aluminium cations leads to the formation of solid solutions of ferrum and aluminium oxyhydroxides. Originality/value The main technological properties of pigments are determined by the anionic and cationic composition. Colour characteristics are determined by the cation-chromophore. The anti-corrosive properties of non-calcined pigments are determined to a greater extent by the presence of the formed hydroxyl ions and the composition of the compounds. The greatest protective effect is observed when using double compounds of metals, the dissociation constants of which differ significantly. The protective effect is mainly determined by the slowdown of the anode process. Anions containing aluminium atoms accelerate the corrosion processes.

The influence of the bath stirring on the structure and properties of Ni/diamond composite coatings produced electrochemically

The paper presents the results of investigations of inluence of the bath’s stirring on structure and properties of Ni/diamond compo¬site coatings. The coatings were produced by electrochemical method in a Watts bath with the addition of 5 g/dm3 of nanodia¬mond powder. Carbon steel was used as the substrate. Tests of the produced coatings included the analysis of their chemical composi¬tion, measurements of surface roughness, tests of microhardness by the Vickers method and identifications of corrosion resistance by the potentiodynamic method. The produced coatings are characterized by a tight structure, a uniform thickness and a good adhesion to the steel substrate. It has been shown that bath stirring largely determines the distribution of the dispersion phase and its content in the composite coatings, which intensively affects the properties of the coatings.

Peculiarities in structure formation and corrosion of cast quasicrystalline Al63Cu25Fe12 and Al63Co24Cu13 alloys in sodium chloride aqueous solution

In this work the structure and corrosion behavior of quasicrystalline cast Al63Cu25Fe12 and Al63Co24Cu13 alloys in 5-% sodium chloride solution (рН 6.9–7.1) were investigated. The alloys were cooled at 5 К/s. The structure of the samples was studied by methods of quantitative metallography, X-ray analysis, and scanning electron microscopy. Corrosion properties were determined by the potentiodynamic method. The made investigations confirm the formation of stable quasicrystalline icosahedral (y) and decagonal (D) phases in the structure of Al63Cu25Fe12 and Al63Co24Cu13 alloys correspondingly. In 5-% sodium chloride solution, the investigated alloys corrode under electrochemical mechanisms with oxygen depolarization. Compared with Al63Cu25Fe12 alloy, Al63Co24Cu13 alloy has a less negative value of free corrosion potential (–0.43 V and–0.66 V, respectively), and its electrochemical passivity region extends due to the inhibition of anodic processes. A corrosion current density, calculated from (E,lgi)-curve, for Al63Co24Cu13 alloy amounts to 0.18 mА/сm2 and for Al63Cu25Fe12 alloy – to 0.20 mА/сm2. The lower corrosion resistance of Al63Cu25Fe12 alloy may be explained by the presence of iron-containing phases in its structure. Based on obtained results, the Al63Co24Cu13 alloy was recommended as a coating material for rocket-and-space equipment working in a marine climate.

Prospects for the Use of Pigments Obtained from Iron-Containing Sludge in the Composition of Construction and Paint compositions

Promising areas of application of pigments obtained on the basis of industrial wastes and containing a number of impurities are considered. The quality of the pigment obtained by the alternative technology from iron-containing sludge was evaluated in comparison with the red iron oxide pigments of the KA TU 2322-166-05011907-98 (Russia) and YIPIN S130 (China) grades. Quality indicators are stated and analyzed relative to the requirements of TU 2322-166-05011907-98. Primer GF-021 was analyzed for compliance with GOST 25129-82 and for the presence of anticorrosion properties by the potentiodynamic method and in the salt spray chamber. Pigments in the composition of fine-grained concrete were investigated for their coloring ability and effect on strength characteristics at the age of 1, 3, 7, 28 days. Deviations and competitive advantages of the pigment obtained by alternative technology are determined with respect to the standard both in the composition of the primer GF-021 and in the composition of painted fine-grained concrete.

Structure and corrosion in NaCl solution of quasicrystalline Al–Cu–Fe cast alloys and thin films

For the first time, quasicrystalline Al60Cu28Fe12 films with 260 nm thickness cooled at 1012–1014 K/s were produced by the modernized method of three-electrode ion-plasma sputtering. Films were deposited on NaCl substrate. The structure of as-sputtered films was investigated in comparison with that of as-cast specimens by methods of quantitative metallography, X-ray analysis, and scanning electron microscopy. Corrosion behavior in 5% NaCl aqueous solution was studied by potentiodynamic method and model tests. In the structure of the as-cast Al–Cu–Fe alloy, the quasicrystalline icosahedral i-phase was established to co-exist with λ -Al13Fe4 , τ-AlCu(Fe), η-AlCu, and θ-Al2Cu crystalline phases and occupy ~56 % of the alloy volume. The Al–Cu–Fe film contains dispersive quasicrystalline i-phase (~3 nm in size) that is stable up to 723 К. Corrosion of the as-sputtered Al–Cu–Fe film runs at the lower rate as compared with that of the as-cast alloy of the same composition. Model corrosion tests for 1, 2, 3, 4, 8 days with 5% NaCl solution at 293 K indicate that the investigated Al–Cu–Fe film remains virtually untouched by corrosion. No marks of pittings typical for as-cast Al–Cu–Fe alloys are observed on the film surface affected by saline solution.

Influence of Heat Treatment on Corrosion Properties of Non-Alloy Steel in Acidic Environment

The article presents the influence of heat treatment on corrosion properties of non-alloy steel. This steel is used in machine elements. Heat treatment has a major impact on corrosion resistance of steel materials. Laboratory methods for measuring the corrosion rate consist of Electrochemical Impedance Spectroscopy and polarization curves. Instead of these types, there are also industrial methods of velocity corrosion measurements like researches in natural conditions and coupons corrosimetry. These days the most popular techniques of corrosion measurements are electrochemical measurements. In order to conduct impact assessments influent of heat treatment to corrosion properties there is need to proceed few steps like prepare samples, carry out heat treatment, hardness measurements, metallographical examination, prepare samples for corrosion and proceed corrosion researches by potentiodynamic method. An important element during researches is corrosion allowance, which has an impact influent on corrosion properties. This is the most popular and efficient method of corrosion protection. These days for corrosion protection are use paints or zinc coatings, cathode protection or stainless.