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16 pages, 6762 KiB

Open AccessFeature PaperArticle

Surface Characteristics of Vacuum-Plasma-Sprayed Reinforced Stainless Steel Coatings with TiC Particles

by Iasmina-Mădălina Anghel (Petculescu), Diana Uțu, Ion Mitelea, Albert Titus Constantin and Ion-Dragoș Uțu

Coatings 2024, 14(3), 289; https://doi.org/10.3390/coatings14030289 - 27 Feb 2024

Viewed by 743

Abstract

Fe-based coatings reinforced with TiC particles exhibit outstanding properties and are widely recognized as highly promising coatings or components with superior performance. In the present study, composite materials using a powder mixture of AISI 316 stainless steel and TiC particles were deposited by [...] Read more.

Fe-based coatings reinforced with TiC particles exhibit outstanding properties and are widely recognized as highly promising coatings or components with superior performance. In the present study, composite materials using a powder mixture of AISI 316 stainless steel and TiC particles were deposited by vacuum plasma spraying onto a S235 low alloyed steel substrate. The coating and the base material were characterized in terms of microstructure and surface properties. The metallographic analysis of the deposited coating revealed the uniform distribution of the TiC into the stainless steel matrix. The results show that the presence of tungsten carbide particles improved the hardness and tribological properties of the composite coating compared with the S235 base material. The wear resistance of the coating was approximately seven times higher than that of the low alloyed steel substrate. The electrochemical corrosion resistance of the coating in chloride media was much higher than that of the base material. Full article

(This article belongs to the Special Issue Recent Advances in Thin Films Deposited by Vacuum Methods)

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17 pages, 34598 KiB

Open AccessArticle

Surface and Electrical Characterization of Non-Stoichiometric Semiconducting Thin-Film Coatings Based on Ti-Co Mixed Oxides Obtained by Gas Impulse Magnetron Sputtering

by Patrycja Pokora, Damian Wojcieszak, Jarosław Domaradzki and Paulina Kapuścik

Coatings 2024, 14(1), 59; https://doi.org/10.3390/coatings14010059 - 30 Dec 2023

Viewed by 815

Abstract

This article presents a detailed investigation of non-stoichiometric (Ti,Co)O_x thin films prepared using the Gas Impulse Magnetron Sputtering (GIMS) technique. The films were prepared with various Co contents (3 at.%, 19 at.%, 44 at.%, and 60 at.%) and characterized for their material [...] Read more.

This article presents a detailed investigation of non-stoichiometric (Ti,Co)O_x thin films prepared using the Gas Impulse Magnetron Sputtering (GIMS) technique. The films were prepared with various Co contents (3 at.%, 19 at.%, 44 at.%, and 60 at.%) and characterized for their material composition, microstructure, and electrical properties. The films exhibited an ohmic behavior with linear current-voltage (I-V) characteristics, and their resistivity values ranged from approximately 10⁻³ to 10⁴ Ω·cm. The highest resistivity was observed in the film with 3 at.% Co content. Thermoelectric measurements revealed that all of the prepared films displayed n-type semiconducting properties, with the Seebeck coefficient (S) tending close to zero. The resistivity of the films decreased as the temperature increased, affirming their semiconducting nature. The activation energy (E_a) values, determined using the Arrhenius formula, ranged from 0.0058 eV to 0.267 eV, with the highest E_a observed for films containing 3 at.% Co. Additionally, the films’ surface topography and microstructure were examined through Atomic Force Microscopy (AFM) and optical profiler techniques. The results showed that the films had smooth, crack-free surfaces with remarkable homogeneity. The surface diversification decreased with the increase in cobalt in the (Ti,Co)O_x films. Full article

(This article belongs to the Special Issue Recent Advances in Thin Films Deposited by Vacuum Methods)

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11 pages, 2583 KiB

Open AccessArticle

Flexural Strength and Vickers Microhardness of Graphene-Doped SnO₂ Thin-Film-Coated Polymethylmethacrylate after Thermocycling

by Canan Akay, Gülce Çakmak, Mustafa Borga Donmez, Samir Abou-Ayash, Emre Mumcu, Suat Pat and Burak Yilmaz

Coatings 2023, 13(6), 1106; https://doi.org/10.3390/coatings13061106 - 16 Jun 2023

Viewed by 1235

Abstract

Removable dental prostheses are commonly fabricated using polymethylmethacrylate, a material that does not have favorable mechanical properties and needs reinforcement with particles such as graphene. The aim of this study was to evaluate the flexural strength (FS) and Vickers microhardness of a heat-polymerized [...] Read more.

Removable dental prostheses are commonly fabricated using polymethylmethacrylate, a material that does not have favorable mechanical properties and needs reinforcement with particles such as graphene. The aim of this study was to evaluate the flexural strength (FS) and Vickers microhardness of a heat-polymerized polymethylmethacrylate coated with graphene-doped stannic oxide (SnO₂) thin films using a thermionic vacuum arc method after thermocycling. Forty bar-shaped specimens (65 × 10 × 3 mm) were fabricated using a heat-polymerized denture base resin and divided into four groups according to the graphene-doped SnO₂ thin film surface coating performed: No-coat (uncoated), Coat-15 s (coating duration of 15 s), Coat-20 s (coating duration of 20 s), and Coat-30 s (coating duration of 30 s) (n = 10). The thermionic vacuum arc method was used to coat both surfaces of the specimens of each test group with varying durations, and surface coating was verified using Fourier Transform Infrared Spectroscopy. Specimens were subjected to 10,000 cycles of thermocycling. Atomic force microscopy was used to evaluate the surfaces of all specimens before and after thermocycling. Microhardness values were measured five times and averaged. Then, each specimen was subjected to a three-point bending test, and FS values were calculated. Data were analyzed using one-way analysis of variance and Bonferroni tests (α = 0.05). Differences among test groups were nonsignificant when FS data were considered (p = 0.605). However, significant differences were observed among test groups when Vickers microhardness data were considered (p < 0.001). Coat-30 s had the highest hardness (p ≤ 0.003), while the difference among remaining groups were nonsignificant (p ≥ 0.166). Graphene-doped SnO₂ thin film surface coatings did not significantly affect the FS of tested heat-polymerized denture base resin but increased the Vickers microhardness when the coating duration was 30 s. Full article

(This article belongs to the Special Issue Recent Advances in Thin Films Deposited by Vacuum Methods)

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12 pages, 2428 KiB

Open AccessArticle

The Influence of Magnetron Sputtering Process Temperature on ZnO Thin-Film Properties

by Paulina Kaim, Krzysztof Lukaszkowicz, Marek Szindler, Magdalena M. Szindler, Marcin Basiaga and Barbara Hajduk

Coatings 2021, 11(12), 1507; https://doi.org/10.3390/coatings11121507 - 07 Dec 2021

Cited by 8 | Viewed by 2284

Abstract

The important research direction in surface engineering and photovoltaics is the development of new materials that can replace the previously used expensive films. A prospective compound is zinc oxide (ZnO), characterized by optical and electrical properties similar to ITO and a lower production [...] Read more.

The important research direction in surface engineering and photovoltaics is the development of new materials that can replace the previously used expensive films. A prospective compound is zinc oxide (ZnO), characterized by optical and electrical properties similar to ITO and a lower production cost. One of the key factors influencing the properties of the ZnO thin films is the technique and parameters of their production. The comprehensive investigation results of the influence of ZnO thin-films deposition process temperature on their structure, optical properties, and adhesion are presented in the paper. ZnO films were deposited by the magnetron sputtering method. The structural characteristics of the tested films were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffractometry (XRD) and Raman spectroscopy, while the optical properties of the films were studied by the UV/VIS spectroscopy. Thickness and adhesion measurements of the obtained films were performed using the spectroscopic ellipsometry technique and the scratch test, respectively. The obtained research results showed the influence of the deposition process temperature on the morphology, crystallite size and adhesion of the thin films to the substrate. The effect of process temperature on optical properties, the value of the optical bandgap and crystal structures were analyzed and described. The results of this work have a meaning for the development of surface engineering and may serve as a clue in future studies in the field of modern photovoltaic structures. Full article

(This article belongs to the Special Issue Recent Advances in Thin Films Deposited by Vacuum Methods)

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13 pages, 7197 KiB

Open AccessArticle

Application of ALD Thin Films on the Surface of the Surgical Scalpel Blade

by Magdalena Szindler, Marek Szindler, Marcin Basiaga, Wojciech Łoński and Paulina Kaim

Coatings 2021, 11(9), 1096; https://doi.org/10.3390/coatings11091096 - 11 Sep 2021

Cited by 8 | Viewed by 3115

Abstract

The article describes biomaterials and surgical instruments, in particular surgical cutting tools. In addition, the functions of coatings and the layer vapor deposition methods are described. In the experimental component of the study, zinc oxide thin film was deposited on the surgical knife [...] Read more.

The article describes biomaterials and surgical instruments, in particular surgical cutting tools. In addition, the functions of coatings and the layer vapor deposition methods are described. In the experimental component of the study, zinc oxide thin film was deposited on the surgical knife blades by the atomic layer deposition (ALD) method with a varying number of cycles. The structures of the deposited thin films were investigated using a Raman spectrometer and the surface topography of the samples was examined using atomic force microscopy and scanning electron microscopy. The adhesion of the thin films was tested using the micro-scratch method. The corrosion resistance was also tested. Surgical instruments coated with non-allergenic metal oxide coatings, containing metal structures that reduce the growth of bacteria, could significantly decrease the risk of undesirable reactions of the body during and after surgery. Full article

(This article belongs to the Special Issue Recent Advances in Thin Films Deposited by Vacuum Methods)

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18 pages, 5535 KiB

Open AccessArticle

Analysis of Different Complex Multilayer PACVD Coatings on Nanostructured WC-Co Cemented Carbide

by Danko Ćorić, Mateja Šnajdar Musa, Matija Sakoman and Željko Alar

Coatings 2021, 11(7), 823; https://doi.org/10.3390/coatings11070823 - 08 Jul 2021

Cited by 6 | Viewed by 2136

Abstract

The development of cemented carbides nowadays is aimed at the application and sintering of ultrafine and nano-sized powders for the production of a variety of components where excellent mechanical properties and high wear resistance are required for use in high temperature and corrosive [...] Read more.

The development of cemented carbides nowadays is aimed at the application and sintering of ultrafine and nano-sized powders for the production of a variety of components where excellent mechanical properties and high wear resistance are required for use in high temperature and corrosive environment conditions. The most efficient way of increasing the tribological properties along with achieving high corrosion resistance is coating. Using surface processes (modification and/or coating), it is possible to form a surface layer/base material system with properties that can meet modern expectations with acceptable production costs. Three coating systems were developed on WC cemented carbides substrate with the addition of 10 wt.% Co using the plasma-assisted chemical vapor deposition (PACVD) method: single-layer TiN coating, harder multilayer gradient TiCN coating composed of TiN and TiCN layers, and the hardest multilayer TiBN coating composed of TiN and TiB₂. Physical and mechanical properties of coated and uncoated samples were investigated by means of quantitative depth profile (QDP) analysis, nanoindentation, surface layer characterization (XRD analysis), and coating adhesion evaluation using the scratch test. The results confirm the possibility of obtaining nanostructured cemented carbides of homogeneous structure without structural defects such as eta phase or unbound carbon providing increase in hardness and fracture toughness. The lowest adhesion was detected for the single-layer TiN coating, while coatings with a complex architecture (TiCN, TiBN) showed improved adhesion. Full article

(This article belongs to the Special Issue Recent Advances in Thin Films Deposited by Vacuum Methods)

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14 pages, 6979 KiB

Open AccessArticle

Structure and Corrosion Behavior of TiO₂ Thin Films Deposited by ALD on a Biomedical Magnesium Alloy

by Aneta Kania, Magdalena M. Szindler and Marek Szindler

Coatings 2021, 11(1), 70; https://doi.org/10.3390/coatings11010070 - 08 Jan 2021

Cited by 22 | Viewed by 3309

Abstract

Magnesium alloys have been investigated as temporary biomaterials for orthopedic applications. Despite their high osseointegration and mechanical (bone-like) properties, Mg alloys quickly degrade in simulated physiological media. Surface coatings can be deposited onto Mg alloys to slow the corrosion rate of these biomaterials [...] Read more.

Magnesium alloys have been investigated as temporary biomaterials for orthopedic applications. Despite their high osseointegration and mechanical (bone-like) properties, Mg alloys quickly degrade in simulated physiological media. Surface coatings can be deposited onto Mg alloys to slow the corrosion rate of these biomaterials in chloride-rich environments. TiO₂ films show high potential for improving the corrosion resistance of magnesium alloys. This article presents the structural observations and corrosion behavior of TiO₂ thin films deposited onto a MgCa2Zn1Gd3 alloy using atomic layer deposition (ALD). Surface morphologies were observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM), and Raman analysis of the deposited TiO₂ films was also carried out. The corrosion behavior of the uncoated alloy and the alloy coated with TiO₂ was measured in Ringer’s solution at 37 °C using electrochemical and immersion tests. The microscopic observations of the TiO₂ thin films with a thickness of about 52.5 and 70 nm showed that the surface morphology was homogeneous without visible defects on the TiO₂ surface. The electrochemical and immersion test results showed that the thin films decreased the corrosion rate of the studied Mg-based alloy, and the corrosion resistance was higher in the thicker TiO₂ film. Full article

(This article belongs to the Special Issue Recent Advances in Thin Films Deposited by Vacuum Methods)

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Review

Jump to: Research

16 pages, 1747 KiB

Open AccessReview

Perspectives in Prevention of Biofilm for Medical Applications

by Julia Lisoń, Anna Taratuta, Zbigniew Paszenda, Magdalena Szindler and Marcin Basiaga

Coatings 2022, 12(2), 197; https://doi.org/10.3390/coatings12020197 - 02 Feb 2022

Cited by 12 | Viewed by 2600

Abstract

The opportunity of decreasing the development of biofilm on the implant surface is one of the biggest research problems. It is connected with the existing prevention of microorganism hyperplasia. The application of numerous modifications is concerned with surface treatments leading to minimizing bacterial [...] Read more.

The opportunity of decreasing the development of biofilm on the implant surface is one of the biggest research problems. It is connected with the existing prevention of microorganism hyperplasia. The application of numerous modifications is concerned with surface treatments leading to minimizing bacterial colonization. In the case of non-use antibacterial therapy, this leads to tissue infection. It can lead to a decreased opportunity to fight infection using antibiotherapy. One way is to decrease the increasing biofilm application which requires a method of modification. These techniques ensure properties like homogeneity or repeatability. The structure and chemical composition are changed with methods like CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), sol–gel, or ALD (Atomic Layer Deposition). Antibacterial properties of metals are connected with their impact on proteins and the nuclear proliferation of fibroblasts, causing improvement in biocompatibility and also growth corrosion resistance, and the decline of biofilm adhesion. The prevention of biofilm with medicines and antibiotics is a crowded-out treatment. Traditional methods of preventing biofilm are based on compounds that kill or inhibit the growth of the microbes but at the same time lead to frequent development of resistance to antibiotics. This review summarizes the current knowledge of reducing and preventing the creation of biofilm. Full article

(This article belongs to the Special Issue Recent Advances in Thin Films Deposited by Vacuum Methods)

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