Special Issue "Surface Treatment Technology of Metals and Alloys"

A special issue of Metals (ISSN 2075-4701).

Deadline for manuscript submissions: closed (31 March 2019).

Special Issue Editor

Prof. Dr. Krzysztof Rokosz
E-Mail Website
Guest Editor
Department of Mechanical Engineering, Koszalin University of Technology, 75-453 Koszalin, Poland
Interests: Plasma Electrolytic Oxidation (PEO); Micro arc Oxidation (MAO); electropolishing (EP); magnetoelectropolishing (MEP); biomaterials (titanium, tantalum, niobium, and their alloys); surface characterization; XPS, GDOES, SEM, EDS; corrosion studies; 2D & 3D roughness measurements
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Special Issue Information

Dear Colleagues,

In recent decades, metals and new alloys with modified surface properties have experienced steady development. These new materials are designed to be used both in various industry branches, as well as in biomedical applications. The point is that modified mechanical, electrochemical, and antibacterial properties may be improved thanks to different changes introduced to the surface layer of metals and alloys. The new surface technology engineering covers modifications and improvements introduced by laser treatments, chemical and electrochemical polishing, magnetoelectropolishing, passivation, anodic oxidation, electrophoretic deposition, ion implantation, plasma electrolytic oxidation, chemical or physical vapor deposition, as well as by sol-gel processing. Nowadays, designing of materials properties is one of the top science domains, allowing for predicting the behavior of material under extreme environmental conditions. Special attention to surface quality is of importance prior to their production. This Special Issue is aimed to be focused on new achievements and directed to everyone interested in widely understood surface engineering of metals and alloys. The theme is interdisciplinary, thus I invite you to submit original research and review articles, as well as short communications, related to both experimental and theoretical studies.

Prof. Dr. Krzysztof Rokosz
Guest Editor

Manuscript Submission Information

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Keywords

  • surface functionalization and modification
  • electropolishing (EP, MEP)
  • electrophoretic deposition (EPD)
  • ion implantation (IM)
  • plasma electrolytic oxidation (micro arc oxidation)
  • chemical or physical vapor deposition (CVD, PVD)
  • anodic oxidation
  • laser treatment, sol-gel coatings
  • biomaterials
  • self-assembling structures

Published Papers (11 papers)

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Research

Open AccessArticle
Influence of Shot Peening Treatment in Erosion Wear Behavior of High Chromium White Cast Iron
Metals 2019, 9(9), 933; https://doi.org/10.3390/met9090933 - 27 Aug 2019
Abstract
High alloy white cast irons (WCI) play an important role in many industrial fields such as mining, cement industry, or grinding due to their high hardness and wear resistance. In all these processes, white cast iron components must work under erosion and abrasion [...] Read more.
High alloy white cast irons (WCI) play an important role in many industrial fields such as mining, cement industry, or grinding due to their high hardness and wear resistance. In all these processes, white cast iron components must work under erosion and abrasion conditions. Many investigations have been carried out with the aim of improving the mechanical properties of this type of alloys. Wear resistance depends on the mechanical properties, mainly hardness. Thus, the WCI are typically heat treated in order to modify its microstructure, improving its tribological and wear behavior. The aim of this study is to propose a mechanical surface treatment, shot peening, as an alternative to global heat treatments, due to its capacity to induce phase transformation and microstructural modification, at the same time that it improves the mechanical properties of materials. Characterization of different treated samples was performed by means of microstructural characterization, X-ray diffraction analysis, SEM observation, hardness and roughness measurements, and erosion tests. The results show that shot peening treatment is able to transform residual austenite and increase hardness in the top surface layer of the material. Both effects contribute to improve the erosion wear behavior of the WCI. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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Open AccessArticle
Electropolishing of Stainless Steel in Laboratory and Industrial Scale
Metals 2019, 9(8), 854; https://doi.org/10.3390/met9080854 - 05 Aug 2019
Abstract
Transposing the process scale from laboratory to industrial conditions is a difficult issue that applies to many sectors of the industry. As far as electropolishing of stainless steel is concerned, the limitations connected with a significant increase in the area of electropolished surface [...] Read more.
Transposing the process scale from laboratory to industrial conditions is a difficult issue that applies to many sectors of the industry. As far as electropolishing of stainless steel is concerned, the limitations connected with a significant increase in the area of electropolished surface should be considered, along with the possibility of defects that may emerge. This paper compares the results of electropolishing of stainless steel in the laboratory and in industrial conditions. For the analyzed conditions, it was determined that the best results, both in laboratory and industrial conditions, were obtained at temperature of 35 °C and current density of 8 A·dm−2. High temperatures resulted in the emergence of defects on the surface, in particular for industrial samples. The defects were visualized by metallographic images with Nomarski contrast and atomic force microscopy. X-ray photoelectron spectroscopy tests were used to analyze the composition of the passive layer on the electropolished surfaces. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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Open AccessArticle
Calculation of the Mixture Flow in a Low-Pressure Carburizing Process
Metals 2019, 9(4), 439; https://doi.org/10.3390/met9040439 - 15 Apr 2019
Abstract
The right selection of carburizing gas flow rates in the low-pressure carburization process is a key factor in terms of its efficiency. However, a correct calculation of the amount of carburizing gas required for uniform carburization of parts, taking into account the process [...] Read more.
The right selection of carburizing gas flow rates in the low-pressure carburization process is a key factor in terms of its efficiency. However, a correct calculation of the amount of carburizing gas required for uniform carburization of parts, taking into account the process temperature and batch size, is still problematic. For this reason, modern carburizing processes are carried out using an excessive belaying flow of carburizing gases. In this work steel parts (16MnCr5) were carburized in a variable-flow carburizing process (960 °C) individually matched to each segment of saturation. The effect of the variable-flow on the microstructure, surface hardness, and case hardness depth was evaluated and compared to that of a control group. It was proven that the amount of the mixture used in the variable-flow carburizing process can be significantly reduced to 54% of that consumed during the regular constant-flow carburizing without affecting the properties of the hardened layer of the steel parts. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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Open AccessArticle
Investigation of Microstructure, Nanohardness and Corrosion Resistance for Oxi-Nitrocarburized Low Carbon Steel
Metals 2019, 9(2), 190; https://doi.org/10.3390/met9020190 - 06 Feb 2019
Cited by 1
Abstract
A role of oxi-nitrocarburizing technique for low-carbon steel was intensively evaluated as a means of reducing the problem of corrosion in gas nitrocarburizing, which is a vital disadvantage of gas nitrocarburizing. Oxi-nitrocarburizing was carried out by a two-step process: Gas nitrocarburizing at 560 [...] Read more.
A role of oxi-nitrocarburizing technique for low-carbon steel was intensively evaluated as a means of reducing the problem of corrosion in gas nitrocarburizing, which is a vital disadvantage of gas nitrocarburizing. Oxi-nitrocarburizing was carried out by a two-step process: Gas nitrocarburizing at 560 °C and oxidation. In order to characterize two different methods of oxi-nitrocarburizing, oxidation was performed under two different conditions: Air and steam as oxygen sources. To analyze the microstructural, physical, and chemical properties of the thin oxide layer and nitride layer, which are the surface hardened layers formed on low-carbon steel by oxi-nitrocarburizing, several methods, such as electron probe microanalysis (EPMA), electron backscattered diffraction (EBSD), scanning electron microscopy (SEM), nanoindentation tests, and potentiodynamic polarization tests were applied. The results indicated that the EPMA and EBSD methods are powerful techniques for the analysis of microstructure, such as phase analysis and metallic element distribution in the oxide layer of magnetite and compound layer of ε-phase and γ′-phase, for oxi-nitrocarburized low-carbon steel. Additionally, the nanohardness using the nanoindentation test and corrosion resistance using the potentiodynamic polarization test for the oxi-nitrocarburized specimens are useful methods to understand the mechanical and corrosion properties of the surface hardened layer. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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Open AccessArticle
General Regression Model for Predicting Surface Topography after Abrasive Blasting
Metals 2018, 8(11), 938; https://doi.org/10.3390/met8110938 - 13 Nov 2018
Cited by 1
Abstract
Abrasive blasting modifies the surface state of pre-treated materials in terms of surface irregularities. Bearing in mind that the roughness characteristics affect the components functionality, it is essential to study and evaluation the surface state of pre-treated materials. The paper deals with evaluation [...] Read more.
Abrasive blasting modifies the surface state of pre-treated materials in terms of surface irregularities. Bearing in mind that the roughness characteristics affect the components functionality, it is essential to study and evaluation the surface state of pre-treated materials. The paper deals with evaluation of relation between individual parameters of roughness of the blasted surfaces by the correlation analysis. Based on the measured values on the surfaces which were blasted by various types of blasting devices, the correlation matrix was set and the standard of statistic importance of correlation between the monitored parameters was determined from it. The correlation coefficient was also set. There were found regression models using ANOVA (ANalysis Of Variance). Based on the analysis of the results were also proposed sets of roughness parameters, which can be used in the assessment of the blasted surfaces. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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Open AccessArticle
Hydrothermal Surface Treatment of Biodegradable Mg-Materials
Metals 2018, 8(11), 894; https://doi.org/10.3390/met8110894 - 01 Nov 2018
Cited by 1
Abstract
Paper presents study on the hydrothermal treatment for hydroxyapatite layer formation on the different biodegradable Mg-substrates. The evaluation of corrosion resistance in Ringer’s solution and contact angle measurements in glycerol were performed. Alloys and composites substrates obtained by mechanical alloying and powder metallurgy [...] Read more.
Paper presents study on the hydrothermal treatment for hydroxyapatite layer formation on the different biodegradable Mg-substrates. The evaluation of corrosion resistance in Ringer’s solution and contact angle measurements in glycerol were performed. Alloys and composites substrates obtained by mechanical alloying and powder metallurgy route are characterized by submicron range microstructure, which is responsible for further surface processing characteristic. Hydrothermal treatment in Ca-EDTA (ethylenediaminetetraacetic acid calcium disodium salt) led to formation of hydroxyapatite layers, which improves both the corrosion resistance and surface wetting properties compared to microcrystalline magnesium. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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Open AccessArticle
Laser Cladding In-Situ Ti(C,N) Particles Reinforced Ni-Based Composite Coatings Modified with CeO2 Nanoparticles
Metals 2018, 8(8), 601; https://doi.org/10.3390/met8080601 - 02 Aug 2018
Cited by 3
Abstract
To improve the wear resistance of titanium alloy parts used in the engineering applications, in-situ formed Ti(C,N) particles reinforcing Ni-based composite coatings are fabricated on Ti6Al4V alloys by the laser cladding technique using Ni60, C, TiN, and small amounts of CeO2 nanoparticles [...] Read more.
To improve the wear resistance of titanium alloy parts used in the engineering applications, in-situ formed Ti(C,N) particles reinforcing Ni-based composite coatings are fabricated on Ti6Al4V alloys by the laser cladding technique using Ni60, C, TiN, and small amounts of CeO2 nanoparticles mixed powders as the pre-placed materials. Firstly, the formation mechanism of Ti(C,N) particles as a reinforced phase in the coating is investigated. Then, the influences of CeO2 nanoparticles on microstructures and wear resistance of the coatings are analyzed. It is indicated that the large Ti(C,N) particles form around TiN particles, and the small Ti(C,N) particles form through independent nucleation. CeO2 nanoparticles play important roles in increasing the nucleation rate and improving the precipitation of Ti(C,N), hence the microstructures and wear resistance of the coatings are apparently improved after adding CeO2 nanoparticles. It is observed that the 1 wt % content of CeO2 additive in the pre-placed powders is the best choice for the wear resistance of the coatings. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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Open AccessArticle
Evaluation of Surface Characteristics and Hemocompatibility on the Oxygen Plasma-Modified Biomedical Titanium
Metals 2018, 8(7), 513; https://doi.org/10.3390/met8070513 - 03 Jul 2018
Cited by 4
Abstract
Oxygen plasma with different treatment powers and durations was utilized to modify the biomedical pure titanium (Ti) surface in the present study. The superficial, microstructural and biological properties of the plasma-oxidized samples were investigated using the electron microscopy, X-ray photoemission spectroscopy, grazing incidence [...] Read more.
Oxygen plasma with different treatment powers and durations was utilized to modify the biomedical pure titanium (Ti) surface in the present study. The superficial, microstructural and biological properties of the plasma-oxidized samples were investigated using the electron microscopy, X-ray photoemission spectroscopy, grazing incidence X-ray diffractometer, contact angle goniometer and blood clotting time assay. During different treatment powers and durations, the island-like nanostructural rutile-TiO2 layer and dimple-like nanostructural rutile-TiO2 layer were generated on the surfaces of the plasma-oxidized samples, respectively. It was also found that the plasma-oxidized sample with a rough oxide layer resulted in the formation of a higher wettability. Moreover, the blood clotting time assay indicated that the plasma-oxidized samples exhibited the adhesion behaviors of red blood cells. As the Ti surface underwent plasma oxidation at 280 W for 30 min, it not only generates a rough nanostructural rutile-TiO2 layer, but also presents an excellent hemocompatibility. Therefore, these findings demonstrate that oxygen plasma modification is a potential approach to promote the hemocompatibility of biomedical pure Ti surface. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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Open AccessArticle
Effect of C2H2/H2 Gas Mixture Ratio in Direct Low-Temperature Vacuum Carburization
Metals 2018, 8(7), 493; https://doi.org/10.3390/met8070493 - 28 Jun 2018
Abstract
The effect of the acetylene and hydrogen gases mixture ratios in direct low-temperature vacuum carburization was investigated. The gas ratio is an important parameter for producing free radicals in carburization. The free radicals can remove the natural oxide film by strong reaction of [...] Read more.
The effect of the acetylene and hydrogen gases mixture ratios in direct low-temperature vacuum carburization was investigated. The gas ratio is an important parameter for producing free radicals in carburization. The free radicals can remove the natural oxide film by strong reaction of the hydrocarbons, and then thermodynamic activity can be increased. When the gas ratio was below one, carbon-supersaturated expanded austenite layers were formed on the surface of the AISI 316L stainless steel, which had a maximum carbon solubility up to 11.5 at% at 743 K. On the other hand, when the gas ratio was above one, the carbon concentration of the layers was low even if the process time was increased enough to reach the maximum carbon solubility. As a result, the carbon concentration underneath the surface was determined to be highly dependent on the gas mixture ratio of acetylene and hydrogen. In conclusion, it is necessary to restrict the ratio of acetylene and hydrogen gases in the total mixture of gases to form an expanded austenite layer with high carbon concentration in direct low-temperature vacuum carburization. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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Open AccessArticle
Characterization of Porous Phosphate Coatings Enriched with Calcium, Magnesium, Zinc and Copper Created on CP Titanium Grade 2 by Plasma Electrolytic Oxidation
Metals 2018, 8(6), 411; https://doi.org/10.3390/met8060411 - 02 Jun 2018
Cited by 3
Abstract
In the paper, the effect of voltage increase (from 500 VDC up to 650 VDC) on the structure and chemical composition of the porous coating on titanium made by Plasma Electrolytic Oxidation is presented. Phosphates-based coatings enriched with calcium, magnesium, [...] Read more.
In the paper, the effect of voltage increase (from 500 VDC up to 650 VDC) on the structure and chemical composition of the porous coating on titanium made by Plasma Electrolytic Oxidation is presented. Phosphates-based coatings enriched with calcium, magnesium, zinc, and copper in electrolyte based on 1 L of 85% concentrated H3PO4, with additions of Ca(NO3)2·4H2O, and Mg(NO3)2∙6H2O, and Zn(NO3)2∙6H2O, and Cu(NO3)2∙3H2O, are described. The morphology and chemical and phase composition are evaluated using SEM, EDS, XRD, XPS, GDOES, and CLSM. Based on these analyses, it was found that PEO coatings are porous and enriched with calcium, magnesium, zinc and copper. They consist mainly of the amorphous phase, which is more visible for higher voltages; this is correlated with an increase in the total PEO coating thickness (the higher the voltage, the thicker the PEO coating). However, for 650 VDC, an amorphous phase and titanium substrate were also recorded, with a signal from Ti2P2O7 crystalline that was not observed for lower voltages. It was also found that all obtained coatings may be divided into three sub-layers, i.e., porous, semiporous, and transitional. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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Open AccessArticle
Multilayer-Forming Behavior of Cr Nitrides and Carbides for Thermoreactive Deposition
Metals 2018, 8(6), 400; https://doi.org/10.3390/met8060400 - 30 May 2018
Abstract
The effect of a nitride layer on the forming behavior of CrN and (Cr, Fe)7C3 multilayers for thermoreactive deposition (TRD) was investigated. Plasma nitriding followed by TRD (PN-TRD) produced a larger coating thickness than the case of direct TRD with [...] Read more.
The effect of a nitride layer on the forming behavior of CrN and (Cr, Fe)7C3 multilayers for thermoreactive deposition (TRD) was investigated. Plasma nitriding followed by TRD (PN-TRD) produced a larger coating thickness than the case of direct TRD with no plasma nitriding. For PN-TRD, an Fe2-3N layer of 10 μm in thickness was produced on AISI 52100 steels using plasma nitriding, followed by TRD using a mixed powder composed of 30 wt % Cr, 2 wt % NH4Cl, and 68 wt % Al2O3. During TRD at 800 °C, a CrN layer of 2 μm in thickness was formed along with a thin layer of mixed carbide (Cr7C3) and nitride (CrN) on top. As the deposition temperature was increased to 950 °C, a new layer of Cr7C3 was formed underneath the outermost layer composed of mixed Cr7C3 and CrN. At 950 °C, a Cr-rich zone indicated a thickness of ~7 μm. As the deposition time increased to 3 h at 950 °C, a new layer of (Cr, Fe)7C3 was produced at the interface between the CrN formed at 800 °C and the base metal. This layer formed because of the abundant resources of Cr and C provided from the TRD powder and base metal, respectively. The multilayer and interface were concretely filled without the formation of voids as the TRD time increased to 6 h at 950 °C. The TRD process on a pre-nitrided layer was successfully applied to produce multilayers of CrN and Cr7C3. Full article
(This article belongs to the Special Issue Surface Treatment Technology of Metals and Alloys)
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