Nanomaterials

Editorial

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3 pages, 237 KiB

Open AccessEditorial

Development of Nanocomposite Coatings

by Zulfiqar A. Khan, Mian H. Nazir and Adil Saeed

Nanomaterials 2022, 12(24), 4377; https://doi.org/10.3390/nano12244377 - 08 Dec 2022

Cited by 1 | Viewed by 917

Abstract

This Special Issue in Nanomaterials, “Development of Nanocomposite Coatings”, was set up with the aim to provide authors with an opportunity to showcase their latest developments in this field [...] Full article

(This article belongs to the Special Issue Development of Nanocomposite Coatings)

Research

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15 pages, 4670 KiB

Open AccessArticle

Synthesis of Magnetic Fe₃O₄ Nano Hollow Spheres for Industrial TNT Wastewater Treatment

by Shafi Ur Rehman, Sana Javaid, Muhammad Shahid, Mutawara Mahmood Baig, Badar Rashid, Caroline R. Szczepanski and Sabrina J. Curley

Nanomaterials 2022, 12(5), 881; https://doi.org/10.3390/nano12050881 - 07 Mar 2022

Cited by 6 | Viewed by 2958

Abstract

The aim of the present work was to synthesize magnetite (Fe₃O₄) nano hollow spheres (NHS) via simple, one-pot, template-free, hydrothermal method. The structural, morphological, and surface analysis of Fe₃O₄ NHS were studied by scanning electron microscopy [...] Read more.

The aim of the present work was to synthesize magnetite (Fe₃O₄) nano hollow spheres (NHS) via simple, one-pot, template-free, hydrothermal method. The structural, morphological, and surface analysis of Fe₃O₄ NHS were studied by scanning electron microscopy (SEM), x-ray diffraction technique (XRD), Fourier transform infrared spectroscopy FTIR and burner-Emmett-teller (BET). The as obtained magnetic (Fe₃O₄) NHS were used as an adsorbent for treating industrial trinitrotoluene (TNT) wastewater to reduce its Chemical Oxygen Demand (COD) values. Adsorption capacity (Qe) of the NHS obtained is 70 mg/g, confirming the attractive forces present between adsorbent (Fe₃O₄ NHS) and adsorbate (TNT wastewater). COD value of TNT wastewater was reduced to >92% in 2 h at room temperature. The adsorption capacity of Fe₃O₄ NHS was observed as a function of time, initial concentration, pH, and temperature. The applied Fe₃O₄ NHS was recovered for reuse by simply manipulating its magnetic properties with slight shift in pH of the solution. A modest decrease in Qe (5.0–15.1%) was observed after each cycle. The novel Fe₃O₄ NHS could be an excellent candidate for treating wastewater generated by the intermediate processes during cyclonite, cyclotetramethylene-tetranitramine (HMX), nitroglycerin (NG) production and other various environmental pollutants/species. Full article

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23 pages, 6392 KiB

Open AccessArticle

Microstructure, Mechanical and Tribological Properties of Advanced Layered WN/MeN (Me = Zr, Cr, Mo, Nb) Nanocomposite Coatings

by Kateryna Smyrnova, Martin Sahul, Marián Haršáni, Alexander Pogrebnjak, Volodymyr Ivashchenko, Vyacheslav Beresnev, Vyacheslav Stolbovoy, Ľubomír Čaplovič, Mária Čaplovičová, Ľubomír Vančo, Martin Kusý, Alexey Kassymbaev, Leonid Satrapinskyy and Dominik Flock

Nanomaterials 2022, 12(3), 395; https://doi.org/10.3390/nano12030395 - 26 Jan 2022

Cited by 15 | Viewed by 3191

Abstract

Due to the increased demands for drilling and cutting tools working at extreme machining conditions, protective coatings are extensively utilized to prolong the tool life and eliminate the need for lubricants. The present work reports on the effect of a second MeN (Me [...] Read more.

Due to the increased demands for drilling and cutting tools working at extreme machining conditions, protective coatings are extensively utilized to prolong the tool life and eliminate the need for lubricants. The present work reports on the effect of a second MeN (Me = Zr, Cr, Mo, Nb) layer in WN-based nanocomposite multilayers on microstructure, phase composition, and mechanical and tribological properties. The WN/MoN multilayers have not been studied yet, and cathodic-arc physical vapor deposition (CA-PVD) has been used to fabricate studied coating systems for the first time. Moreover, first-principles calculations were performed to gain more insight into the properties of deposited multilayers. Two types of coating microstructure with different kinds of lattices were observed: (i) face-centered cubic (fcc) on fcc-W₂N (WN/CrN and WN/ZrN) and (ii) a combination of hexagonal and fcc on fcc-W₂N (WN/MoN and WN/NbN). Among the four studied systems, the WN/NbN had superior properties: the lowest specific wear rate (1.7 × 10⁻⁶ mm³/Nm) and high hardness (36 GPa) and plasticity index H/E (0.93). Low surface roughness, high elastic strain to failure, Nb₂O₅ and WO₃ tribofilms forming during sliding, ductile behavior of NbN, and nanocomposite structure contributed to high tribological performance. The results indicated the suitability of WN/NbN as a protective coating operating in challenging conditions. Full article

(This article belongs to the Special Issue Development of Nanocomposite Coatings)

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14 pages, 7956 KiB

Open AccessArticle

Surface Alloying and Improved Property of Nb on TC4 Induced by High Current Pulsed Electron Beam

by Xueze Du, Nana Tian, Conglin Zhang, Peng Lyu, Jie Cai and Qingfeng Guan

Nanomaterials 2021, 11(11), 2906; https://doi.org/10.3390/nano11112906 - 29 Oct 2021

Cited by 4 | Viewed by 1554

Abstract

In this paper, an Nb alloying layer on a TC4 alloy was fabricated by using high-current pulsed electron beam (HCPEB) irradiation to improve surface performance. X-ray diffraction (XRD), optical microscopy (OM), laser surface microscope (LSM), scanning electron microscopy (SEM) and transmission electron microscopy [...] Read more.

In this paper, an Nb alloying layer on a TC4 alloy was fabricated by using high-current pulsed electron beam (HCPEB) irradiation to improve surface performance. X-ray diffraction (XRD), optical microscopy (OM), laser surface microscope (LSM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the phase composition and microstructure of the surface layer. The microhardness, wear tests and corrosion resistance were also examined. The results show that after HCPEB alloying, a Nb-alloyed layer was formed with about 3.6 μm in thickness on the surface of the sample, which was mainly composed of α’-Ti martensite, β-Ti equiaxial crystals, and NbTi₄ particles. After HCPEB irradiation, the surface hardness, wear resistance and corrosion resistance of Nb alloying layer on TC4 alloy were improved compared to the initial samples. Full article

(This article belongs to the Special Issue Development of Nanocomposite Coatings)

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17 pages, 2670 KiB

Open AccessArticle

Influence of Calcium Silicate and Hydrophobic Agent Coatings on Thermal, Water Barrier, Mechanical and Biodegradation Properties of Cellulose

by Saravanan Chandrasekaran, Remi Castaing, Alvaro Cruz-Izquierdo and Janet L. Scott

Nanomaterials 2021, 11(6), 1488; https://doi.org/10.3390/nano11061488 - 04 Jun 2021

Cited by 2 | Viewed by 2635

Abstract

Thin films of cellulose and cellulose–CaSiO₃ composites were prepared using 1-ethyl-3-methylimidazolium acetate (EMIMAc) as the dissolution medium and the composites were regenerated from an anti-solvent. The surface hydrophilicity of the resultant cellulose composites was lowered by coating them with three different hydrophobizing [...] Read more.

Thin films of cellulose and cellulose–CaSiO₃ composites were prepared using 1-ethyl-3-methylimidazolium acetate (EMIMAc) as the dissolution medium and the composites were regenerated from an anti-solvent. The surface hydrophilicity of the resultant cellulose composites was lowered by coating them with three different hydrophobizing agents, specifically, trichloro(octadecyl)silane (TOS), ethyl 2-cyanoacrylate (E2CA) and octadecylphosphonic acid (ODPA), using a simple dip-coating technique. The prepared materials were subjected to flame retardancy, water barrier, thermal, mechanical and biodegradation properties analyses. The addition of CaSiO₃ into the cellulose increased the degradation temperature and flame retardant properties of the cellulose. The water barrier property of cellulose–CaSiO₃ composites under long term water exposure completely depends on the nature of the hydrophobic agents used for the surface modification process. All of the cellulose composites behaved mechanically as a pure elastic material with a glassy state from room temperature to 250 °C, and from 20% to 70% relative humidity (RH). The presence of the CaSiO₃ filler had no effect on the elastic modulus, but it seemed to increase after the TOS surface treatment. Biodegradability of the cellulose was evaluated by enzyme treatments and the influence of CaSiO₃ and hydrophobic agents was also derived. Full article

(This article belongs to the Special Issue Development of Nanocomposite Coatings)

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12 pages, 3338 KiB

Open AccessArticle

Enhanced Mechanical Properties and Microstructure of Accumulative Roll-Bonded Co/Pb Nanocomposite

by Maryam Karbasi, Eskandar Keshavarz Alamdari, Elahe Amirkhani Dehkordi, Zulfiqar A. Khan and Fariborz Tavangarian

Nanomaterials 2021, 11(5), 1190; https://doi.org/10.3390/nano11051190 - 30 Apr 2021

Cited by 7 | Viewed by 1681

Abstract

Lead composites have been used as anodes in the electrowinning process to produce metals such as copper and zinc. Manufacturing stable lead anodes with appropriate mechanical and chemical properties is required to improve the performance of the electrowinning process. In this study, an [...] Read more.

Lead composites have been used as anodes in the electrowinning process to produce metals such as copper and zinc. Manufacturing stable lead anodes with appropriate mechanical and chemical properties is required to improve the performance of the electrowinning process. In this study, an accumulative roll bonding (ARB) method was used to fabricate a Co/Pb nanocomposite. Utilizing the ARB method can help us to achieve a uniform structure with enhanced mechanical properties via severe plastic deformation. The results showed that suitable tensile properties were obtained in Pb–0.5%Co–10pass samples. The tensile strength and strain of these samples were 2.51 times higher and 83.7% lower than that of as-cast pure Pb. They also showed creep resistance and hardness up to 1.8 and 2.5 times more than that of as-cast pure Pb. The ARB technique uniformly distributed Co particles in the Pb matrix. The enhanced strength of Pb samples was observed in the composite including grain sizes of less than 50 nm as a result of hindering the recovery phenomenon. The particle size of the Co distributed in the Pb matrix was 353 ± 259 nm. Compared to conventional methods, the ARB process improved the mechanical properties of Co/Pb composites and can open a new horizon to fabricating this composite in metal industries. Full article

(This article belongs to the Special Issue Development of Nanocomposite Coatings)

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19 pages, 9088 KiB

Open AccessArticle

Effects of Different TiO₂ Nanoparticles Concentrations on the Physical and Antibacterial Activities of Chitosan-Based Coating Film

by Yage Xing, Xuanlin Li, Xunlian Guo, Wenxiu Li, Jianwen Chen, Qian Liu, Qinglian Xu, Qin Wang, Hua Yang, Yuru Shui and Xiufang Bi

Nanomaterials 2020, 10(7), 1365; https://doi.org/10.3390/nano10071365 - 13 Jul 2020

Cited by 56 | Viewed by 3699

Abstract

In this investigation, the effect of different concentrations of titanium dioxide (TiO₂) nanoparticles (NPs) on the structure and antimicrobial activity of chitosan-based coating films was examined. Analysis using scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed that the modified [...] Read more.

In this investigation, the effect of different concentrations of titanium dioxide (TiO₂) nanoparticles (NPs) on the structure and antimicrobial activity of chitosan-based coating films was examined. Analysis using scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed that the modified TiO₂ NPs were successfully dispersed into the chitosan matrix, and that the roughness of the chitosan-TiO₂ nanocomposites were significantly reduced. Moreover, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses indicated that the chitosan interacted with TiO₂ NPs and possessed good compatibility, while a thermogravimetric analysis (TGA) of the thermal properties showed that the chitosan-TiO₂ nanocomposites with 0.05% TiO₂ NPs concentration had the best thermal stability. The chitosan-TiO₂ nanocomposite exhibited an inhibitory effect on the growth of Escherichia coli and Staphylococcus aureus. This antimicrobial activity of the chitosan-TiO₂ nanocomposites had an inhibition zone ranging from 9.86 ± 0.90 to 13.55 ± 0.35 (mm). These results, therefore, indicate that chitosan-based coating films incorporated with TiO₂ NPs might become a potential packaging system for prolonging the shelf-life of fruits and vegetables. Full article

(This article belongs to the Special Issue Development of Nanocomposite Coatings)

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25 pages, 4657 KiB

Open AccessArticle

Magnetic Porous Controlled Fe₃O₄–Chitosan Nanostructure: An Ecofriendly Adsorbent for Efficient Removal of Azo Dyes

by Tiago M. Freire, Lillian M. U. D. Fechine, Danilo C. Queiroz, Rafael M. Freire, Juliano C. Denardin, Nágila M. P. S. Ricardo, Thaina N. B. Rodrigues, Diego R. Gondim, Ivanildo J. S. Junior and Pierre B. A. Fechine

Nanomaterials 2020, 10(6), 1194; https://doi.org/10.3390/nano10061194 - 19 Jun 2020

Cited by 36 | Viewed by 3542

Abstract

In this work, chitosan/magnetite nanoparticles (ChM) were quickly synthesized according to our previous report based on co-precipitation reaction under ultrasound (US) irradiation. Besides ChM was in-depth structurally characterized, showing a crystalline phase corresponding to magnetite and presenting a spheric morphology, a “nanorod”-type morphology [...] Read more.

In this work, chitosan/magnetite nanoparticles (ChM) were quickly synthesized according to our previous report based on co-precipitation reaction under ultrasound (US) irradiation. Besides ChM was in-depth structurally characterized, showing a crystalline phase corresponding to magnetite and presenting a spheric morphology, a “nanorod”-type morphology was also obtained after increasing reaction time for eight minutes. Successfully, both morphologies presented a nanoscale range with an average particle size of approximately 5–30 nm, providing a superparamagnetic behavior with saturation magnetization ranging from 44 to 57 emu·g⁻¹. As ChM nanocomposites have shown great versatility considering their properties, we proposed a comparative study using three different amine-based nanoparticles, non-surface-modified and surface-modified, for removal of azo dyes from aqueous solutions. From nitrogen adsorption–desorption isotherm results, the surface-modified ChMs increased the specific surface area and pore size. Additionally, the adsorption of anionic azo dyes (reactive black 5 (RB5) and methyl orange (MO)) on nanocomposites surface was pH-dependent, where surface-modified samples presented a better response under pH 4 and non-modified one under pH 8. Indeed, adsorption capacity results also showed different adsorption mechanisms, molecular size effect and electrostatic attraction, for unmodified and modified ChMs, respectively. Herein, considering all results and nanocomposite-type structure, ChM nanoparticles seem to be a suitable potential alternative for conventional anionic dyes adsorbents, as well as both primary materials source, chitosan and magnetite, are costless and easily supplied. Full article

(This article belongs to the Special Issue Development of Nanocomposite Coatings)

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Review

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40 pages, 15359 KiB

Open AccessReview

Plasma Electrolytic Oxidation (PEO) Process—Processing, Properties, and Applications

by Soumya Sikdar, Pramod V. Menezes, Raven Maccione, Timo Jacob and Pradeep L. Menezes

Nanomaterials 2021, 11(6), 1375; https://doi.org/10.3390/nano11061375 - 22 May 2021

Cited by 115 | Viewed by 7612

Abstract

Plasma electrolytic oxidation (PEO) is a novel surface treatment process to produce thick, dense metal oxide coatings, especially on light metals, primarily to improve their wear and corrosion resistance. The coating manufactured from the PEO process is relatively superior to normal anodic oxidation. [...] Read more.

Plasma electrolytic oxidation (PEO) is a novel surface treatment process to produce thick, dense metal oxide coatings, especially on light metals, primarily to improve their wear and corrosion resistance. The coating manufactured from the PEO process is relatively superior to normal anodic oxidation. It is widely employed in the fields of mechanical, petrochemical, and biomedical industries, to name a few. Several investigations have been carried out to study the coating performance developed through the PEO process in the past. This review attempts to summarize and explain some of the fundamental aspects of the PEO process, mechanism of coating formation, the processing conditions that impact the process, the main characteristics of the process, the microstructures evolved in the coating, the mechanical and tribological properties of the coating, and the influence of environmental conditions on the coating process. Recently, the PEO process has also been employed to produce nanocomposite coatings by incorporating nanoparticles in the electrolyte. This review also narrates some of the recent developments in the field of nanocomposite coatings with examples and their applications. Additionally, some of the applications of the PEO coatings have been demonstrated. Moreover, the significance of the PEO process, its current trends, and its scope of future work are highlighted. Full article

(This article belongs to the Special Issue Development of Nanocomposite Coatings)

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