Arc-Sprayed Iron-Based Coatings for Erosion-Corrosion Protection of Boiler Tubes at Elevated Temperatures

Pokhmurskii, V. I.; Студент, М. М.; Gvozdeckii, Volodymyr; Stypnutskyy, Taras; Student, О. Z.; Wielage, B.; Pokhmurska, H.

doi:10.1007/s11666-013-9921-z

Cited by 36 publications

(14 citation statements)

References 14 publications

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“…High-alloyed Fe-based coatings containing a sufficient level of another major alloying element such as Cr or Ni would be a cheaper and a more environmentally friendly alternative to Co-based coatings of specific interest in high demanding applications [5,[10][11][12][13]. Adding minor alloying elements of C or B to high-alloyed Fe-based alloys has been shown to improve both the corrosion and wear resistance of the coatings [14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study of Corrosion Resistance for HVAF-Sprayed Fe- and Co-Based Coatings

2016

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There is an increasing demand to replace Co-based coatings with cheap and environmentally friendly Fe-based coatings in corrosive environments. The main objective of this work was to evaluate whether Fe-based coatings could present a better corrosion performance than Co-based coatings. Therefore, two types of Fe-based and one type of Co-based coatings with chemical compositions (in wt %) of Fe-28Cr-16Ni-1.85C (FeNiCrC), Fe-17Cr-12Ni (FeNiCr), and Co-28Cr-1C (CoCrC) were produced by High Velocity Air Fuel (HVAF) spraying. The corrosion behavior of the coatings was studied comparatively by electrochemical tests in 3.5 wt % NaCl solution at 25˝C. The polarization test results showed that the FeCrNiC coating protected the underlying substrate better than the CoCrC coating, while the FeCrNi coating failed to hinder the penetration of corrosive ions. Electrochemical impedance spectroscopy (EIS) measurements revealed that the solution penetrated into the coating through defects, however the corrosion process slowed down due to clogging of the interconnected defects by corrosion products. Increasing the in-flight average particle temperature from 1400˝C to 1500˝C led to a denser coating with fewer defects which seemed to improve the corrosion resistance of the FeCrNiC coating. The high-alloyed Fe-based coatings had the best corrosion protection performance and can thus be recommended as a potential alternative to Co-based coatings.

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Section: Introductionmentioning

confidence: 99%

A Comparative Study of Corrosion Resistance for HVAF-Sprayed Fe- and Co-Based Coatings

2016

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“…The microstructure was investigated on a Zeiss EVO-XVP-40 electron microscope equipped with an INCA Energy-350 X-ray spectral microanalyzer (Oxford Instruments). The coefficient of microheterogeneity of the coatings was found as follows [4]:…”

Section: Methodsmentioning

confidence: 99%

“…The powder wires are used to get coatings with high mechanical characteristics and, first of all, high hardness (up to 1300 HV) [2]. The procedure of electric-arc metallization can be used for the restoration of various worn-out articles, improvement of the properties or protection of the metallic and nonmetallic surfaces against the abrasive or corrosion wear [3,4]. However, at present, there exists a need in coatings of combined action (wear-and corrosion-resistant simultaneously).…”

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confidence: 99%

Optimization of the Chromium Content of Powder Wires of the Fe–Cr–C and Fe–Cr–B Systems According to the Corrosion Resistance of Electric-Arc Coatings

et al. 2016

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UDC 621.797; 621.793.7We study electric-arc coatings of the Fe-Cr-C and Fe-Cr-B systems. It is shown that chromium content of 12 wt.% is insufficient to guarantee higher corrosion resistance of the coatings in neutral aqueous solutions (as compared with steels) caused by the formation of chromium-based oxides, carbides, and borides. Therefore, the indicated chromium content of the compounds should be taken into account and compensated in finding the chemical composition of powder wires. Its unjustified increase is not reasonable because powder wires are characterized by filling coefficients restricting the possibility of their filling with alloying elements. Therefore, the content of each alloying element in the charge of powder wires should be well justified and determined. For this purpose, we propose to use the relations taking into account the nonlinear distribution of chromium in the lamellas of the coatings caused by their high microheterogeneity and the depletion of their solid solution of the indicated element as a result of the formation of oxides, carbides, and borides on its base.At present, the electric-arc metallization is extensively used in machine building, power-generating industry, mining industry, and other branches of national economy as the cost-effective, most productive, and simple method of gas-thermal spraying [1]. As electrode materials, it is possible to use both solid and powder wires. The powder wires are used to get coatings with high mechanical characteristics and, first of all, high hardness (up to 1300 HV) [2]. The procedure of electric-arc metallization can be used for the restoration of various worn-out articles, improvement of the properties or protection of the metallic and nonmetallic surfaces against the abrasive or corrosion wear [3,4]. However, at present, there exists a need in coatings of combined action (wear-and corrosion-resistant simultaneously). Various parts of the critical aggregates made of structural materials (the rods of hydraulic cylinders of the mining equipment and freight transport, parts of the sheet-output mechanisms of the printing equipment, rods of the stop valves, etc.) and protected by wear-resistant electrolytic chromium operate under the conditions of abrasive wear and boundary friction. The procedure of electrolytic chrome plating is ecologically dangerous and, therefore, the leading researchers throughout the world give much attention to the possibility of its replacement by gas-thermal spraying [5,6]. This is economically efficient because the amount of the required electric energy decreases, the time of application of the coating becomes much by (8-10 times) smaller, the necessity of utilizing toxic wastes disappears, and the material for the coating can be chosen depending on requirements imposed on the coatings.

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“…Technologically, the method of arc spray metallization (ASM) is considered as the simplest and cheapest to obtain coatings, in comparison with the known gas-thermal methods [1][2][3]. Recently, it has been started to the use the electrode materials in the form of special cored wires (CW) for their creation.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Increasing the Air Flow Pressure on the Properties of Coatings During the Arc Spraying of Cored Wires

Студент

Volodymyr

Student

et al. 2019

Strojnícky Časopis - Journal of Mechanical Engineering

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The melting conditions of the electrode wires and the structure of coatings, obtained by the electric arc spraying method depending on the pressure of the spraying air flow, are analysed in the current paper. The effect of air pressure on the spraying angle of the flow of melted metal droplets is demonstrated. It is established that due to the decrease in this spraying angle, the temperature of the droplets increases. In addition, high-speed airflow is more easily captured by smaller molten metal droplets and during the contact with the substrate surface their deformations were more strongly. Due to such phenomenon, the porosity of the coatings was reduced and the number of lamellae, welded to each other, increased. With the increasing pressure of the air flow, the thicknesses of the lamellae were decreased, however, the amount of the oxide phase in the coatings has increased. As a result, the hardness, wear resistance and cohesive strength of the coatings, obtained at a higher pressure of the air flow, have increased, and the level of residual stresses of the first kind in them decreased.

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Arc-Sprayed Iron-Based Coatings for Erosion-Corrosion Protection of Boiler Tubes at Elevated Temperatures

Cited by 36 publications

References 14 publications

A Comparative Study of Corrosion Resistance for HVAF-Sprayed Fe- and Co-Based Coatings

A Comparative Study of Corrosion Resistance for HVAF-Sprayed Fe- and Co-Based Coatings

Optimization of the Chromium Content of Powder Wires of the Fe–Cr–C and Fe–Cr–B Systems According to the Corrosion Resistance of Electric-Arc Coatings

The Effect of Increasing the Air Flow Pressure on the Properties of Coatings During the Arc Spraying of Cored Wires

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