The aim of this study was to determine the suitability of arc sprayed zinc and aluminum coatings as materials for protective coatings of different heating systems. The most aggressive chemical agents occurring in heating water are...
moreThe aim of this study was to determine the suitability of arc sprayed zinc and aluminum coatings as materials for protective coatings of different heating systems. The most aggressive chemical agents occurring in heating water are chloride and sulfate anions. Both ions are responsible for the corrosion of metals due to their high electronegativity and standard electrochemical potential. Water in heating systems should not contain more than 150 mg/L anions, including no more than 50 mg/L of chlorides and 100 mg/L of sulfates. To determine the corrosion resistance of three types of zinc and aluminum coatings, open circuit potential and linear polarization resistance (LPR) tests were conducted in eight alkaline solutions with different sulfate and chloride contents. The SEM/EDS structural properties of sprayed coatings at specific arc process parameters were investigated. Zinc coatings exhibit the most stable corrosion potentials in varying environments but have higher corrosion curren...
Purpose: An analytical model is provided in order to reveal the mechanism of the intermetallic multi-layer formation on a substrate. Thus, formations of the Al3Ni2 – Al3Ni intermetallic multi-layer on the Ni – substrate and Fe3Zn10 –...
morePurpose: An analytical model is provided in order to reveal the mechanism of the intermetallic multi-layer formation on a substrate. Thus, formations of the Al3Ni2 – Al3Ni intermetallic multi-layer on the Ni – substrate and Fe3Zn10 – FeZn10 – FeZn13 intermetallic multi-layer on the Fe (armco) multi-layer are considered.Design/methodology/approach: The intermetallic multi-layers are the products of the undercooled peritectic reactions as this results from the model. Back-diffusion and partitioning as the phenomena accompanying the peritectic reactions are employed to describe the sub-layers growth.Research limitations/implications: The model could be modified to describe the multi-layers formation under the metastable conditions.Practical implications: The modeled descriptions of the mechanism of multi-layer formation seems to be a good tool to control the technologies like: diffusion soldering / brazing or hot dip galvanizing into zinc bath.Originality/value: This is quite new model...
The paper presents results of a research on simulation of magnetic tip-surface interaction as a function of the lift height in the magnetic force microscopy. As expected, magnetic signal monotonically decays with increasing lift height,...
moreThe paper presents results of a research on simulation of magnetic tip-surface interaction as a function of the lift height in the magnetic force microscopy. As expected, magnetic signal monotonically decays with increasing lift height, but the question arises, whether or not optimal lift height eventually exists. To estimate such a lift height simple procedure is proposed in the paper based on the minimization of the fractal dimension of the averaged profile of the MFM signal. In this case, the fractal dimension serves as a measure of distortion of a pure tip-surface magnetic coupling by various side effects, e.g. thermal noise and contribution of topographic features. Obtained simulation results apparently agree with experimental data.
The medium and high temperature tribological behavior of different iron aluminide thermal spray coatings was investigated. Several powders synthesized through different routes (ball milling, self-decomposition, and self-propagating...
moreThe medium and high temperature tribological behavior of different iron aluminide thermal spray coatings was investigated. Several powders synthesized through different routes (ball milling, self-decomposition, and self-propagating high-temperature sintering (SHS)) were evaluated. High heterogeneity of conventional High Velocity Oxygen Fuel (HVOF) coatings plays a vital role in their sliding performance, but as long as their integrity is preserved under high temperature oxidizing conditions, the wear rates are found to be acceptable, as it occurs in the case of ball milled Fe-40Al (at.%) powder. The friction phenomenon and wear mechanisms were analyzed in detail through the wear track morphology, contact surface, and friction coefficients. The occurrence of brittle phases in the sprayed coatings, which are also present when tested at high temperatures, appeared to be crucial in accelerating the coating failure.
A thermodynamic justification for the joint formation is developed on the basis of the diffusion brazing of the Ni/Al/Ni system. The phenomena of dissolution and solidification were included into the description. The first solid/solid...
moreA thermodynamic justification for the joint formation is developed on the basis of the diffusion brazing of the Ni/Al/Ni system. The phenomena of dissolution and solidification were included into the description. The first solid/solid transformation is also discussed. Mainly, a description for the isothermal brazing occurrence in the meta-stable conditions is developed. It involves the application of the criterion of higher temperature of the solid / liquid (s/l) interface. The dissolution of the filler metal in the substrate is described by the N0 – solute concentration within the dissolution zone (liquid film) distinguished at the substrate surface. The selection of the N0− parameter by the dissolution is justified by the Thermocalc calculation of the Ni-Al phase diagram for meta-stable equilibrium. According to the model assumptions, the solidification is accompanied by partitioning or by undercooled peritectic reaction resulting in formation of the intermetallic phase. The avera...
ABSTRACT A modified Sachs method was applied to determine the residual surface stress in Fe-Al type intermetallic coatings deposited on a surface of carbon 1045 steel substrate by a gas detonation spray technique. The detailed theoretical...
moreABSTRACT A modified Sachs method was applied to determine the residual surface stress in Fe-Al type intermetallic coatings deposited on a surface of carbon 1045 steel substrate by a gas detonation spray technique. The detailed theoretical model with a description of device is presented. Compressive stresses in the entire thickness of created coatings is discussed. The influence of chemical composition of powders (applied for coating deposition) on residual stress related to the structural and phase composition, as well as the degree of chemical heterogeneity of the multilayer composite coating system is analyzed. The maximum amplitude of stress on the surface of coatings is within the range of −900 to −1100 MPa for samples without boron additive and between −500 and −600 MPa for samples with boron only. The composition of the powder blend of the FeAl-intermetallic coatings deposited on the surface of the substrate affects significantly the distribution of residual stresses. The structural inhomogeneity and no repeatability of physical and chemical properties of particular structural elements are the reasons for the development of residual stresses system generation within the coating.
ABSTRACT Intermetallic Fe–Al type coatings about 100 μm thick were deposited on a plain carbon steel substrate by D-gun spraying technique. The 40–75 μm size fraction of the feedstock powder was obtained by self-propagating...
moreABSTRACT Intermetallic Fe–Al type coatings about 100 μm thick were deposited on a plain carbon steel substrate by D-gun spraying technique. The 40–75 μm size fraction of the feedstock powder was obtained by self-propagating high-temperature synthesis and sieved prior to D-gun spraying. This powder contained a mixture of Fe–Al type intermetallic phases conventionally appointed FexAly. The Fe–Al coatings were analysed by transmission electron microscopy, selected area electron diffraction, and semi-quantitative energy-dispersive X-ray analysis in micro-areas. Particular attention was paid to the substructure of the individual grains in the coating zone abutting the steel substrate. The Fe–Al coatings have a multi-layer composite structure. The results explain the formation mechanism of the coating microstructure. The powder particles, which were heterogeneous in chemical composition and structure, were heated, highly softened or even partially melted and oxidised while flying from the gun barrel to the substrate. After impacting the substrate or previously deposited material and being shot peened by the following powder particles, they were rapidly cooled and plastically deformed, creating overlapping splats. In the zone adjacent to the substrate, alternating FeAl and Fe2Al5 intermetallic phases formed columnar crystals. The columnar crystal areas were separated by elongated amorphous oxide layers. Areas of mixed equiaxed subgrains of FeAl and Fe3Al phases, fine grains of Fe-rich Fe(Al) solid solution, and micro- and nano-pores were also present.
The morphology of Fe-Al type intermetallic coatings produced by detonation spraying on a 045 steel substrate was described based on the microstructure analysis using transmission electron microscopy (TEM), and selected area electron...
moreThe morphology of Fe-Al type intermetallic coatings produced by detonation spraying on a 045 steel substrate was described based on the microstructure analysis using transmission electron microscopy (TEM), and selected area electron diffraction (SAED) techniques as well as an analysis of chemical composition in microareas (EDS). The TEM was useful in establishing the coating structure in the vicinity of the interface between the substrate and the coating up to the depth of 10 m. Starting from the boundary with the substrate, an amorphous phase (A), then columnar crystals (CC) followed by crystalline grains of Fe3Al were observed. Farther on, the amorphous phase again and grains of the FeAl2 phase were localized. The Fe2Al5 and Fe3Al phases lay close to the coating surface. The phase transformations were completed with calorimetric analysis, which showed heat effects typical for magnetic transformations and ordering. The results indicated to the mechanism of coating formation which c...
The aim of this paper is to present generalized research results and analyses of the quality of coatings produced with self decomposing Fe-Al intermetallic powders deposited on 1045 steel in the gas detonation spraying (GDS). A number of...
moreThe aim of this paper is to present generalized research results and analyses of the quality of coatings produced with self decomposing Fe-Al intermetallic powders deposited on 1045 steel in the gas detonation spraying (GDS). A number of GDS experiments has been carried out with significantly changed operational spraying parameters (the volume of the fuel gas, carrier gas, distance and the frequency of spraying) which define the process energy level directly influencing the quality of the coating. On the basis of the initial results the choice of the process parameters has been made to obtain the most advantageous set of geometrical and physical-mechanical properties of the coating material and substrate. The quality of the coatings was considered by taking into account the grain morphology, chemical content, phase inhomogeneity, cohesive porosity, as well as adhesive porosity in the substrate coating joint. The coating roughness was also considered. It was found that all GDS coatin...
© 2020. The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (CC BY-NC 4.0,
https://creativecommons.org/licenses/by-nc/4.0/deed.en which permits the use, redistribution of the material in any medium or format, transforming and building upon the material, provided that the article is properly cited, the use is noncommercial, and no modifications or adaptations are made. Arch. Metall. Mater. 66 (2021), 1, 181-186
ABSTRACT The paper presents research results of the application of HVOF process for deposition of Fe-Al intermetallic coatings on 1045 steel in the presence of NiAl and NiCr interlayers. The application properties have been investigated...
moreABSTRACT The paper presents research results of the application of HVOF process for deposition of Fe-Al intermetallic coatings on 1045 steel in the presence of NiAl and NiCr interlayers. The application properties have been investigated and the specific multilayer structure of the HVOF coating was analysed (i.e. the grain morphology, inhomogeneity of chemical composition and inhomogeneity of the phase structure. Moreover the cohesive porosity in the coating volume, as well as the adhesive porosity in the substrate/ interlayer/coating boundaries were analysed. Finally the hardness degree of the system was researched. It was found that all the HVOF sprayed coatings researched are built with flat lamellar splats resulting from the powder particles which are HVOF process transformed in their plasticity and geometry. A significant result of the HVOF spraying are intensive changes in the geometry of subsequently deposited grains and high adhesivity and cohesion of the layers. It confirms the high plasticity of the HVOF formed Fe-Al intermetallic coating. Moreover the physical-chemical properties of the interfaces, combined with unique, very dense, lamellar and pore free intermetallic protective coating obtained from Fe-Al powders resulted in new, more advantageous features of the whole HVOF structure which is characterized by the possibility to vary its complexity and properties which, in turn, enabled independent control of its functional properties and considerably reduced negative gradients of stress and temperature influencing the substrate and increasing thus adhesion strength.
The microstructure analysis of Fe-Al intermetallic coating deposited by detonation-gaseous spraying (DGS) on the 045 carbon steel substrate was presented in the paper. The microstructure was investigated using scanning (SEM) and...
moreThe microstructure analysis of Fe-Al intermetallic coating deposited by detonation-gaseous spraying (DGS) on the 045 carbon steel substrate was presented in the paper. The microstructure was investigated using scanning (SEM) and transmission (TEM) electron microscopy, as well as selected area electron diffraction (SAED) techniques. The chemical concentration in microareas was revealed using the energy dispersive X-ray (EDS) spectroscopy technique. The TEM technique was applied to the analysis across the coating as well as close to the coating/substrate interface. The vicinity of the substrate was composed of an amorphous phase and columnar crystals as a result of rapid solidification of the partially melted FeAl powder. The Fe3Al phase was identified inside the coating, while at its surface Fe2Al5, Fe3Al and FeCrAl phases were found. Their occurrence and also the FeAl2O4 phase and aluminium oxide were confirmed by the X-ray diffraction method.
In this paper, mechanical properties of the as-received and aluminide layer coated MAR 247 nickel based superalloy were examined through creep and fatigue tests. The aluminide layer of 20 µm was obtained through the chemical vapor...
moreIn this paper, mechanical properties of the as-received and aluminide layer coated MAR 247 nickel based superalloy were examined through creep and fatigue tests. The aluminide layer of 20 µm was obtained through the chemical vapor deposition (CVD) process in the hydrogen protective atmosphere for 8 h at the temperature of 1040 °C and internal pressure of 150 mbar. A microstructure of the layer was characterized using the scanning electron microscopy (SEM) and X-ray Energy Dispersive Spectroscopy (EDS). It was found that aluminide coating improve the high temperature fatigue performance of MAR247 nickel based superalloy at 900 °C significantly. The coated MAR 247 nickel based superalloy was characterized by the stress amplitude response ranging from 350 MPa to 520 MPa, which is twice as large as that for the uncoated alloy.
The detonation gas spraying method is used to study solidification of the Fe-40Al particles after the D-gun spraying and settled on the water surface. The solidification is divided into two stages. First, the particle solid shell forms...
moreThe detonation gas spraying method is used to study solidification of the Fe-40Al particles after the D-gun spraying and settled on the water surface. The solidification is divided into two stages. First, the particle solid shell forms during the particle contact with the surrounding air / gas. Usually, the remaining liquid particle core is dispersed into many droplets of different diameter. A single Fe-Al particle is described as a body subjected to a rotation and finally to a centrifugal force leading to segregation of iron and aluminum. The mentioned liquid droplets are treated as some spheres rotated freely / chaotically inside the solid shell of the particle and also are subjected to the centrifugal force. The centrifugal force, and first of all, the impact of the particles onto the water surface promote a tendency for making punctures in the particles shell. The droplets try to desert / abandon the mother-particles through these punctures. Some experimental evidences for this ...
Dear colleagues: Dr Nuria Cinca and I will serve as Guest Editors for a special issue of the Coatings journal, based on “Aluminide-based Intermetallic Matrix composite coatings”. This special issue focuses on original research articles...
moreDear colleagues:
Dr Nuria Cinca and I will serve as Guest Editors for a special issue of the Coatings journal, based on “Aluminide-based Intermetallic Matrix composite coatings”. This special issue focuses on original research articles and review papers on all aspects related to the development, characterization and application of transition metal aluminide matrix cermet coatings. Specific details of the different topics covered by this can be found at:
https://www.mdpi.com/journal/coatings/special_issues/Aluminide_Intermetallic_Coating If this is a topic of your interest and you want to participate in this special issue, you have enough time to submit your article before May 2021.
We look forward to hearing from you and hope that the journal can welcome you as a contributing author to this special issue.
Best regards,
Cezary Senderowski
Guest Editor