Research

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10 pages, 50529 KiB

Open AccessArticle

Development of Microstructured Carbon Coatings by Substrate-Catalytic CVD

by Mattia Pierpaoli, Mirosław Sawczak and Anna Dettlaff

Coatings 2021, 11(11), 1403; https://doi.org/10.3390/coatings11111403 - 18 Nov 2021

Cited by 1 | Viewed by 1779

Carbon nanostructured films were synthesized by chemical vapor deposition (CVD) on H18 stainless steel (AISI 440C) sheets with an H₂/CH₄/N₂ gas mixture at various substrate temperatures. During the synthesis, the iron and chromium oxide layer was formed between [...] Read more.

Carbon nanostructured films were synthesized by chemical vapor deposition (CVD) on H18 stainless steel (AISI 440C) sheets with an H₂/CH₄/N₂ gas mixture at various substrate temperatures. During the synthesis, the iron and chromium oxide layer was formed between the steel and carbonaceous layer. The carbon films exhibited wall-like and spherical morphologies and structures, as characterized by scanning electron microscopy and Raman spectroscopy. It was found that the synthesis temperature affects the microsphere density and, therefore, also in the electrochemical behavior. The electrochemical behavior of nanostructured carbon coatings strongly depends on the CVD deposition conditions. The best corrosion resistance (R_p = 11.8 MΩ·cm², I_corr = 4.4 nA·cm⁻²) exhibits a nanostructured carbon sample with a moderate amount of sp²-C-rich carbon microspheres CμSs synthesized at 700 °C. The corrosion resistance of the nanostructured carbon coating is better than raw stainless steel. Full article

(This article belongs to the Special Issue Metal Oxide Films and Their Applications)

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16 pages, 6118 KiB

Open AccessArticle

Influence of Voltage Sags on the Continuity of the Operation and Lifespan of Single-Phase Industrial Robots

by Grzegorz Putynkowski, Krzysztof Woźny, Elzbieta Szychta and Leszek Szychta

Coatings 2021, 11(10), 1229; https://doi.org/10.3390/coatings11101229 - 09 Oct 2021

Cited by 4 | Viewed by 1899

Abstract

Due to the increase in the number of automated processes that employ industrial robots (especially in industrial and laboratory environments, including vacuum systems), and the resulting increase in the number of unresolved service requests, the purpose of the authors’ research was to confirm [...] Read more.

Due to the increase in the number of automated processes that employ industrial robots (especially in industrial and laboratory environments, including vacuum systems), and the resulting increase in the number of unresolved service requests, the purpose of the authors’ research was to confirm the occurrence of disturbances in the form of voltage sags that are not recorded by automation systems and which lead to the destruction of robots or their equipment in areas defined by the characteristics of ITIC/SEMI F47 and CBEMA as being free from such disturbances. The article also describes the environmental classification of robots by their process functionalities/features, and recommends equipment that is able to compensate for these disturbances. Such a classification approach can be an excellent tool for building an exploitation culture and assist the conscious selection of electrical equipment in robotised systems susceptible to disturbances (e.g., robots in load-lock in vacuum environment). Full article

(This article belongs to the Special Issue Metal Oxide Films and Their Applications)

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13 pages, 4773 KiB

Open AccessArticle

Corrosion Behavior of Amorphous Sol–Gel TiO₂–ZrO₂ Nano Thickness Film on Stainless Steel

by Lidija Ćurković, Helena Otmačić Ćurković, Irena Žmak, Mihone Kerolli Mustafa and Ivana Gabelica

Coatings 2021, 11(8), 988; https://doi.org/10.3390/coatings11080988 - 19 Aug 2021

Cited by 7 | Viewed by 2819

Abstract

In this work, a single-layer TiO₂–ZrO₂ thin film is deposited on the AISI 316L austenitic stainless steel by the sol–gel process and the dip coating method to improve its corrosion resistance properties. For the sol preparation, titanium isopropoxide and zirconium [...] Read more.

In this work, a single-layer TiO₂–ZrO₂ thin film is deposited on the AISI 316L austenitic stainless steel by the sol–gel process and the dip coating method to improve its corrosion resistance properties. For the sol preparation, titanium isopropoxide and zirconium butoxide are used as the precursors, yttrium acetate hydrate is used for the ZrO₂ stabilization, i-propanol as the solvent, nitric acid as the catalyst, acetylacetone as the chelating agent, and the distilled water for the hydrolysis. The deposited films are annealed at 400 °C or 600 °C. Morphology and phase composition of the sol–gel TiO₂–ZrO₂ films and powders are analyzed by scanning electron microscopy (SEM) equipped with EDX detector and X-ray diffraction (XRD), respectively. The thickness of the sol–gel TiO₂–ZrO₂ films deposited on the stainless steel is determined by glow discharge optical emission spectrometry (GD-OES). The corrosion behavior of the stainless steel, coated by amorphous films, is evaluated in 3 wt% NaCl and 0.5 mol dm⁻³ HCl by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. It is found that the sol–gel TiO₂–ZrO₂ films with the amorphous structure, deposited by the sol–gel process, and calcined at 400 °C significantly enhance the corrosion properties of AISI 316L in both chloride media. Full article

(This article belongs to the Special Issue Metal Oxide Films and Their Applications)

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14 pages, 5293 KiB

Open AccessArticle

Influence of GLAD Sputtering Configuration on the Crystal Structure, Morphology, and Gas-Sensing Properties of the WO₃ Films

by Arkadiusz Zarzycki, Katarzyna Dyndał, Maciej Sitarz, Jie Xu, Feng Gao, Konstanty Marszałek and Artur Rydosz

Coatings 2020, 10(11), 1030; https://doi.org/10.3390/coatings10111030 - 26 Oct 2020

Cited by 7 | Viewed by 2582

Abstract

In this paper, we describe a deposition method and investigation of the physical properties of WO₃ films. We investigated tungsten oxide due to its potential application as a gas sensor. Thin films of the WO₃ were deposited on glass, silicon, and [...] Read more.

In this paper, we describe a deposition method and investigation of the physical properties of WO₃ films. We investigated tungsten oxide due to its potential application as a gas sensor. Thin films of the WO₃ were deposited on glass, silicon, and alumina substrates by magnetron GLAD sputtering. The crystallinity of films was determined by X-ray diffraction (XRD) and the thickness by X-Ray Reflectivity (XRR) and spectroscopic ellipsometry (SE). Surface morphology, which is important for gas sensitivity, was measured by atomic force microscopy (AFM). We studied the gas-sensing characteristics under exposure to acetone in the 0.1–1.25 ppm range which covers the levels of exhaled breath acetone. We show that WO₃ sensors have different sensitivity for different sputter angle. Furthermore, we demonstrate the influence of temperature during gas content measurement. Full article

(This article belongs to the Special Issue Metal Oxide Films and Their Applications)

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13 pages, 6206 KiB

Open AccessArticle

Multilayer Structure of Reduced Graphene Oxide and Copper Oxide as a Gas Sensor

by Tadeusz Pisarkiewicz, Wojciech Maziarz, Artur Małolepszy, Leszek Stobiński, Dagmara Michoń and Artur Rydosz

Coatings 2020, 10(11), 1015; https://doi.org/10.3390/coatings10111015 - 22 Oct 2020

Cited by 14 | Viewed by 2478

Abstract

Reduced graphene oxide and copper oxide multilayer structures were fabricated in a planar configuration by deposition on both ceramic and Si/SiO₂ substrates with interdigitated Au electrodes by the spray method. SEM (scanning electron microscopy), TEM (transmission electron microscopy), XRD (X-ray diffraction), and [...] Read more.

Reduced graphene oxide and copper oxide multilayer structures were fabricated in a planar configuration by deposition on both ceramic and Si/SiO₂ substrates with interdigitated Au electrodes by the spray method. SEM (scanning electron microscopy), TEM (transmission electron microscopy), XRD (X-ray diffraction), and elemental analysis investigations indicated that graphene oxide (GO) was obtained in a form of interconnected flakes consisting of 6–7 graphene layers for GO with the total thickness of ca. 6 nm and 2–3 layers for rGO with the total thickness of 1 nm. The lateral size of one flake reached up to 10 micrometers. Copper oxide was obtained by the wet chemical method. The number of sequential layers of the sensing structure was optimized to obtain good sensitivity and acceptable response/recovery times in response to the oxidizing nitrogen dioxide atmosphere. Both semiconductor partners revealed p-type conductivity. Formation of isotype heterojunctions between both semiconductor partners was taken into account and their influence on electrical transport explained. Optimized sensor structures revealed relative sensitivities reaching several tens of percent and acceptable response and recovery times in NO₂ concentration ranged from a few to 20 ppm. Possibility of manufacturing sensors working at room temperature was shown, but at the cost of prolonged response/recovery times. Full article

(This article belongs to the Special Issue Metal Oxide Films and Their Applications)

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13 pages, 2273 KiB

Open AccessArticle

GLAD Magnetron Sputtered Ultra-Thin Copper Oxide Films for Gas-Sensing Application

by Artur Rydosz, Katarzyna Dyndał, Wojciech Andrysiewicz, Dominik Grochala and Konstanty Marszałek

Coatings 2020, 10(4), 378; https://doi.org/10.3390/coatings10040378 - 11 Apr 2020

Cited by 22 | Viewed by 3713

Abstract

Copper oxide (CuO) ultra-thin films were obtained using magnetron sputtering technology with glancing angle deposition technique (GLAD) in a reactive mode by sputtering copper target in pure argon. The substrate tilt angle varied from 45 to 85° and 0°, and the sample rotation [...] Read more.

Copper oxide (CuO) ultra-thin films were obtained using magnetron sputtering technology with glancing angle deposition technique (GLAD) in a reactive mode by sputtering copper target in pure argon. The substrate tilt angle varied from 45 to 85° and 0°, and the sample rotation at a speed of 20 rpm was stabilized by the GLAD manipulator. After deposition, the films were annealed at 400 °C/4 h in air. The CuO ultra-thin film structure, morphology, and optical properties were assessed by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), X-ray reflectivity (XRR), and optical spectroscopy. The thickness of the films was measured post-process using a profilometer. The obtained copper oxide structures were also investigated as gas-sensitive materials after exposure to acetone in the sub-ppm range. After deposition, gas-sensing measurements were performed at 300, 350, and 400 °C and 50% relative humidity (RH) level. We found that the sensitivity of the device is related to the thickness of CuO thin films, whereas the best results are obtained with an 8 nm thick sample. Full article

(This article belongs to the Special Issue Metal Oxide Films and Their Applications)

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12 pages, 3217 KiB

Open AccessFeature PaperArticle

Synthesis of Nanoporous TiO₂ with the Use of Diluted Hydrogen Peroxide Solution and Its Application in Gas Sensing

by Orhan Sisman, Nicola Poli, Dario Zappa and Elisabetta Comini

Coatings 2019, 9(10), 681; https://doi.org/10.3390/coatings9100681 - 19 Oct 2019

Cited by 21 | Viewed by 3243

Abstract

The chemical routes of metal oxidation in presence of hydrogen peroxide solutions are tailor-made for the synthesis of biocompatible metal oxide surfaces with clean intermediate and end products, such as oxides, hydroxides, hydrogen and water. The hydrolysis of titanium in hydrogen peroxide solutions [...] Read more.

The chemical routes of metal oxidation in presence of hydrogen peroxide solutions are tailor-made for the synthesis of biocompatible metal oxide surfaces with clean intermediate and end products, such as oxides, hydroxides, hydrogen and water. The hydrolysis of titanium in hydrogen peroxide solutions is particularly interesting for medical applications, forming micro- and nanoscale titania surfaces. In this paper, the content of the hydrolysis solution is revised, allowing the fabrication of gas sensor devices based on nanoporous titania. Nanopore and microcrack formations were discussed in detail by monitoring the structural changes on the thin film surface with field-emission scanning electron microscopy (FE-SEM). A stable rutile crystalline phase was detected by glancing incidence X-ray diffraction (GI-XRD) measurement after repetitive hydrothermal processes. Electrical conductance measurements were carried out at high temperatures (400–600 °C) under humid airflow (40% RH@20 °C) with the injection of various concentrations of a wide set of test compounds (C₂H₃N, CO, H₂, NO₂, C₂H₆O), to observe the sensing capabilities of the material. Furthermore, the humidity effects on the sensing properties toward H₂, CO, and C₂H₆O have been discussed. Full article

(This article belongs to the Special Issue Metal Oxide Films and Their Applications)

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Review

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22 pages, 19922 KiB

Open AccessFeature PaperReview

Semiconducting Metal Oxides: SrTiO₃, BaTiO₃ and BaSrTiO₃ in Gas-Sensing Applications: A Review

by Bartłomiej Szafraniak, Łukasz Fuśnik, Jie Xu, Feng Gao, Andrzej Brudnik and Artur Rydosz

Coatings 2021, 11(2), 185; https://doi.org/10.3390/coatings11020185 - 04 Feb 2021

Cited by 46 | Viewed by 6920

Abstract

In this work, a broad overview in the field of strontium titanate (ST, SrTiO₃)-, barium titanate (BT, BaTiO₃)- and barium strontium titanate (BST, BaSrTiO₃)-based gas sensors is presented and discussed. The above-mentioned materials are characterized by a [...] Read more.

In this work, a broad overview in the field of strontium titanate (ST, SrTiO₃)-, barium titanate (BT, BaTiO₃)- and barium strontium titanate (BST, BaSrTiO₃)-based gas sensors is presented and discussed. The above-mentioned materials are characterized by a perovskite structure with long-term stability and therefore are very promising materials for commercial gas-sensing applications. Within the last 20 years, the number of papers where ST, BT and BST materials were tested as gas-sensitive materials has ten times increased and therefore an actual review about them in this field has been expected by readers, who are researchers involved in gas-sensing applications and novel materials investigations, as well as industry research and development center members, who are constantly searching for gas-sensing materials exhibiting high 3S parameters (sensitivity, selectivity and stability) that can be adapted for commercial realizations. Finally, the NO₂-sensing characteristics of the BST-based gas sensors deposited by the authors with the utilization of magnetron sputtering technology are presented. Full article

(This article belongs to the Special Issue Metal Oxide Films and Their Applications)

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28 pages, 7499 KiB

Open AccessReview

Preparation and Characterization of Nb_xO_y Thin Films: A Review

by Nwanna Charles Emeka, Patrick Ehi Imoisili and Tien-Chien Jen

Coatings 2020, 10(12), 1246; https://doi.org/10.3390/coatings10121246 - 17 Dec 2020

Cited by 26 | Viewed by 5790

Abstract

Niobium oxides (NbO, NbO₂, Nb₂O₅), being a versatile material has achieved tremendous popularity to be used in a number of applications because of its outstanding electrical, mechanical, chemical, and magnetic properties. Nb_xO_y films possess [...] Read more.

Niobium oxides (NbO, NbO₂, Nb₂O₅), being a versatile material has achieved tremendous popularity to be used in a number of applications because of its outstanding electrical, mechanical, chemical, and magnetic properties. Nb_xO_y films possess a direct band gap within the ranges of 3.2–4.0 eV, with these films having utility in different applications which include; optical systems, stainless steel, ceramics, solar cells, electrochromic devices, capacitor dielectrics, catalysts, sensors, and architectural requirements. With the purpose of fulfilling the requirements of a vast variety of the named applications, thin films having comprehensive properties span described by film composition, morphology, structural properties, and thickness are needed. The theory, alongside the research status of the different fabrication techniques of Nb_xO_y thin films are reported in this work. The impact of fabrication procedures on the thin film characteristics which include; film thickness, surface quality, optical properties, interface properties, film growth, and crystal phase is explored with emphases on the distinct deposition process applied, are also described and discussed. Full article

(This article belongs to the Special Issue Metal Oxide Films and Their Applications)

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