APATITIC NANOPOWDERS AND COATINGS: A COMPREHENSIVE REVIEW

2021 ◽  
Author(s):  
RAVINDER PAL SINGH ◽  
UMA BATRA
Keyword(s):  
Sol Gel ◽  
Dip Coating ◽  
Clinical Applications ◽  
Hard Tissue ◽  
Preparation Methods ◽  
Comprehensive Review ◽  
Metallic Substrates ◽  
Surface Modification Techniques ◽  
Dental Applications ◽  
Insight Into

The use of artificial biomaterials has been acclaiming potential therapeutic scope in diverse clinical applications. This review started with the description of the basics of biomaterials, and desirable properties, which are the prerequisites to understand biomaterials. The orthopedic biomaterials, their classification and the importance of calcium phosphate (CaP) materials for hard-tissue applications were utterly discussed. Furthermore, among the various CaP biominerals, the importance of hydroxyapatite (HAP) and its synthesis techniques was comprehensively reviewed. The sol–gel route for the synthesis of HAP nanoparticles and deposition of coatings were systematically studied. Among the metallic substrates, Ti6Al4V alloy remained the focus of this study. Moreover, several film pre-preparation methods were also given due importance. The importance of other surface modification techniques, especially in the context of Ti6Al4V substrates, was also discussed. Among several coating techniques to deposit CaP coatings, special attention was paid to the spin and dip coating techniques. In addition to monolithic HAP coatings, reinforced and antimicrobial HAP coatings were also reviewed from broad perspectives. Therefore, this review provides an in-depth insight into the preparation and properties of apatitic nanoparticles and their coatings for orthopedic and dental applications.

scholarly journals Preparation and Recent Developments of Ti/SnO2-Sb Electrodes

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Fangcheng Cao ◽  
Jingyi Tan ◽  
Shengping Zhang ◽  
Hongqing Wang ◽  
Caizhen Yao ◽  
...  
Keyword(s):  
Specific Conductivity ◽  
Sol Gel ◽  
Research Work ◽  
Chemical Vapor ◽  
Dip Coating ◽  
Industrial Applications ◽  
Chemical Vapor Deposition Method ◽  
Preparation Methods ◽  
As Doping ◽  
Recent Developments

Ti/SnO2-Sb electrode, which is one of the dimensionally stable anode (DSA) electrodes, offers high specific conductivity, excellent electrocatalytic performance, and great chemical stability. For these reasons, Ti/SnO2-Sb electrode has been extensively studied in the fields of wastewater treatment. This review covers essential research work about the advanced oxidation technology and related DSA electrodes. It gives an overview of preparation methods of SnO2 electrodes, including sol-gel method, dip-coating method, electrodeposition method, chemical vapor deposition method, thermal decomposition method, magnetron sputtering method, and hydrothermal method. To extend service life and improve electrocatalytic efficiency, the review provides comprehensive details about the modification technologies of Ti/SnO2-Sb electrode, such as doping modification, composite modification, and structural modification. In addition, the review discusses common problems in industrial applications of Ti/SnO2-Sb electrode and highlights the promising outlook of Ti/SnO2-Sb electrode.

scholarly journals Deposition of Hybrid Photocatalytic Layers for Air Purification Using Commercial TiO2 Powders

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6584
Author(s):  
Ewoud Cosaert ◽  
Cédric Wolfs ◽  
Stéphanie D. Lambert ◽  
Geraldine J. Heynderickx ◽  
Dirk Poelman
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Thin Layers ◽  
Matrix Analysis ◽  
Preparation Methods ◽  
Metallic Substrates ◽  
Alternative Approach ◽  
Volatile Organic ◽  
Different Types ◽  
Long Time

Photocatalytic nanomaterials, using only light as the source of excitation, have been developed for the breakdown of volatile organic compounds (VOCs) in air for a long time. It is a tough challenge to immobilize these powder photocatalysts and prevent their entrainment with the gas stream. Conventional methods for making stable films typically require expensive deposition equipment and only allow the deposition of very thin layers with limited photocatalytic performance. The present work presents an alternative approach, using the combination of commercially available photocatalytic nanopowders and a polymer or inorganic sol–gel-based matrix. Analysis of the photocatalytic degradation of ethanol was studied for these layers on metallic substrates, proving a difference in photocatalytic activity for different types of stable layers. The sol–gel-based TiO2 layers showed an improved photocatalytic activity of the nanomaterials compared with the polymer TiO2 layers. In addition, the used preparation methods require only a limited amount of photocatalyst, little equipment, and allow easy upscaling.

In-Situ Study of NiO Growth on Textured Nickel Tape Using Environmental Scanning Electron Microscope (ESEM) and Hot Stage

2001 ◽  
Vol 7 (S2) ◽  
pp. 1276-1277
Author(s):  
Y. Akin ◽  
R.E. Goddard ◽  
W. Sigmund ◽  
Y.S. Hascicek
Keyword(s):  
Buffer Layer ◽  
Lattice Mismatch ◽  
Sol Gel ◽  
Surface Oxidation ◽  
Dip Coating ◽  
Buffer Layers ◽  
Superconducting Film ◽  
Environmental Scanning ◽  
Cold Rolling And Annealing

Deposition of highly textured ReBa2Cu3O7−δ (RBCO) films on metallic substrates requires a buffer layer to prevent chemical reactions, reduce lattice mismatch between metallic substrate and superconducting film layer, and to prevent diffusion of metal atoms into the superconductor film. Nickel tapes are bi-axially textured by cold rolling and annealing at appropriate temperature (RABiTS) for epitaxial growth of YBa2Cu3O7−δ (YBCO) films. As buffer layers, several oxide thin films and then YBCO were coated on bi-axially textured nickel tapes by dip coating sol-gel process. Biaxially oriented NiO on the cube-textured nickel tape by a process named Surface-Oxidation- Epitaxy (SEO) has been introduced as an alternative buffer layer. in this work we have studied in situ growth of nickel oxide by ESEM and hot stage.Representative cold rolled nickel tape (99.999%) was annealed in an electric furnace under 4% hydrogen-96% argon gas mixture at 1050°C to get bi-axially textured nickel tape.

Porous Gel Coatings Obtained by Phase Separation in ORMOSIL System

2000 ◽  
Vol 628 ◽  
Author(s):  
Kazuki Nakanishi ◽  
Souichi Kumon ◽  
Kazuyuki Hirao ◽  
Hiroshi Jinnai
Keyword(s):  
Phase Separation ◽  
Reaction Time ◽  
Volume Fraction ◽  
Sol Gel ◽  
Reaction Times ◽  
Dip Coating ◽  
Coating Solution ◽  
Coating Method ◽  
Gel Phase ◽  
Dip Coating Method

ABSTRACTMacroporous silicate thick films were prepared by a sol-gel dip-coating method accompanied by the phase separation using methyl-trimethoxysilane (MTMS), nitric acid and dimethylformamide (DMF) as starting components. The morphology of the film varied to a large extent depending on the time elapsed after the hydrolysis until the dipping of the coating solution. On a glass substrate, the films prepared by early dipping had inhomogeneous submicrometer-sized pores on the surface of the film. At increased reaction times, relatively narrow sized isolated macropores were observed and their size gradually decreased with the increase of reaction time. On a polyester substrate, in contrast, micrometer-sized isolated spherical gel domains were homogeneously deposited by earlier dippings. With an increase of reaction time, the volume fraction of the gel phase increased, then the morphology of the coating transformed into co-continuous gel domains and macropores, and finally inverted into the continuous gel domains with isolated macropores. The overall morphological variation with the reaction time was explained in terms of the phase separation and the structure freezing by the forced gelation, both of which were induced by the evaporation of methanol during the dipping operation.

scholarly journals Aqueous Sol-Gel Synthesis of Different Iron Ferrites: From 3D to 2D

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1554
Author(s):  
Justinas Januskevicius ◽  
Zivile Stankeviciute ◽  
Dalis Baltrunas ◽  
Kęstutis Mažeika ◽  
Aldona Beganskiene ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Substrate Surface ◽  
Sol Gel ◽  
Synthesis Method ◽  
Xrd Analysis ◽  
Dip Coating ◽  
Yttrium Iron ◽  
Iron Garnet ◽  
Dip Coating Technique ◽  
Sol Gel Synthesis

In this study, an aqueous sol-gel synthesis method and subsequent dip-coating technique were applied for the preparation of yttrium iron garnet (YIG), yttrium iron perovskite (YIP), and terbium iron perovskite (TIP) bulk and thin films. The monophasic highly crystalline different iron ferrite powders have been synthesized using this simple aqueous sol-gel process displaying the suitability of the method. In the next step, the same sol-gel solution was used for the fabrication of coatings on monocrystalline silicon (100) using a dip-coating procedure. This resulted, likely due to substrate surface influence, in all coatings having mixed phases of both garnet and perovskite. Thermogravimetric (TG) analysis of the precursor gels was carried out. All the samples were investigated by X-ray powder diffraction (XRD) analysis. The coatings were also investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Mössbauer spectroscopy. Magnetic measurements were also carried out.

The Application of the Blockchain Technology in Voting Systems

2021 ◽  
Vol 54 (3) ◽  
pp. 1-28
Author(s):  
Jun Huang ◽  
Debiao He ◽  
Mohammad S. Obaidat ◽  
Pandi Vijayakumar ◽  
Min Luo ◽  
...  
Keyword(s):  
Research Agenda ◽  
Future Research ◽  
Voting Systems ◽  
Comprehensive Review ◽  
Formal Expression ◽  
Future Research Agenda ◽  
Blockchain Technology ◽  
Peer Network ◽  
Peer To Peer Network ◽  
Insight Into

Voting is a formal expression of opinion or choice, either positive or negative, made by an individual or a group of individuals. However, conventional voting systems tend to be centralized, which are known to suffer from security and efficiency limitations. Hence, there has been a trend of moving to decentralized voting systems, such as those based on blockchain. The latter is a decentralized digital ledger in a peer-to-peer network, where a copy of the append-only ledger of digitally signed and encrypted transactions is maintained by each participant. Therefore, in this article, we perform a comprehensive review of blockchain-based voting systems and classify them based on a number of features (e.g., the types of blockchain used, the consensus approaches used, and the scale of participants). By systematically analyzing and comparing the different blockchain-based voting systems, we also identify a number of limitations and research opportunities. Hopefully, this survey will provide an in-depth insight into the potential utility of blockchain in voting systems and device future research agenda.

scholarly journals Development of Adhesive, Bioactive and Antibacterial Titania Sol-Gel Coating on Titanium Substrate by Dip-Coating Technique

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 243
Author(s):  
Diana Horkavcová ◽  
Quentin Doubet ◽  
Gisèle Laure Lecomte-Nana ◽  
Eva Jablonská ◽  
Aleš Helebrant
Keyword(s):  
Simulated Body Fluid ◽  
Body Fluid ◽  
Sol Gel ◽  
Titanium Substrate ◽  
Dip Coating ◽  
Coating Technique ◽  
Metal Implants ◽  
Excellent Adhesion ◽  
Titania Sol ◽  
Dip Coating Technique

The sol-gel method provides a wide variety of applications in the medical field. One of these applications is the formation of coatings on the metal implants. The coatings containing specific additive can enhance or improve the existing surface properties of the substrate. In this work, titania sol-gel coatings were doped with two forms of silver (AgNO3, Ag3PO4) and synthetic hydroxyapatite and applied on the titanium samples by dip-coating technique. After drying and slow firing, all coatings were characterized with scanning electron microscopy. Thin coatings were successfully prepared with excellent adhesion to the substrate (measured by ASTM D 3359-2), despite cracks. Coatings containing silver and hydroxyapatite demonstrated a 100% antibacterial effect against Escherichia coli after 24 h. The bioactivity of the coatings containing hydroxyapatite tested in modified simulated body fluid under static-dynamic conditions was confirmed by bone-like hydroxyapatite precipitation. To better understand the interaction of the coatings with simulated body fluid (SBF), changes of Ca2+ and (PO4)3− ions concentrations and pH values were studied.

Photocatalytic Degradation of Methylene Blue by NiO Thin Films under Solar Light Irradiation

2019 ◽  
Vol 56 ◽  
pp. 152-157 ◽  
Author(s):  
Abdelouahab Noua ◽  
Hichem Farh ◽  
Rebai Guemini ◽  
Oussama Zaoui ◽  
Tarek Diab Ounis ◽  
...  
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Sol Gel ◽  
Visible Region ◽  
Optical Transmittance ◽  
Dip Coating ◽  
Light Irradiation ◽  
Solar Light ◽  
Solar Light Irradiation

Nickel oxide (NiO) thin films were successfully deposited by sol-gel dip-coating method on glass substrates. The structural, morphological and optical properties in addition to the photocatalytic activity of the prepared films were investigated. The results show that the films have a polycrystalline NiO cubic structure with dense NiO grains and average optical transmittance in the visible region. The photocatalytic properties of the films were studied through the degradation of methylene blue and 89% of degradation was achieved for 4.5h of solar light irradiation exposure which indicates the capability of NiO photocatalytic activity.

The effect of the withdrawal speed on properties of nickel oxide thin films

2019 ◽  
Vol 234 (10) ◽  
pp. 647-655
Author(s):  
Zohra Nazir Kayani ◽  
Atiqa Aslam ◽  
Rabia Ishaque ◽  
Syeda Nosheen Zahra ◽  
Hifza Hanif ◽  
...  
Keyword(s):  
Thin Films ◽  
Nickel Oxide ◽  
Band Gap ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Dip Coating ◽  
Oxide Thin Films ◽  
Withdrawal Speed ◽  
Sem Micrograph ◽  
Nickel Oxide Thin Films

Abstract Nickel oxide thin films have been prepared by sol-gel dip-coating technique on glass substrate. It is shown that nickel oxide thin films have poly crystalline nature. Nickel oxide thin films exhibit high transmission (39–85%) in the wavelength range of 400–900 nm, strong absorption between 300 and 400 nm wavelengths and decrease of band gap values are in the range 3.69–3.27 eV with increase of withdrawal speed. High band gap at low withdrawal speed is because of the small average crystallite size, which decreases with increase in withdrawal speed. The SEM micrograph shows cubic crystallites and surface of thin films become dense, smooth and homogeneous with an increase in withdrawal speed. Assessment of nickel oxide deposition conditions provides gateway for effective and cheap solar cells.

Characterization of ordered mesoporous films on silicon (001) surface using X-ray and electron diffraction

2005 ◽  
Vol 38 (1) ◽  
pp. 211-216 ◽  
Author(s):  
Pang-Hung Liu ◽  
Kuei-Jung Chao ◽  
Xing-Jian Guo ◽  
Kuo-Ying Huang ◽  
Yen-Ru Lee ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Sol Gel ◽  
Dip Coating ◽  
Silica Film ◽  
Continuous Film ◽  
X Ray ◽  
Transmission Electron ◽  
Ordered Mesoporous ◽  
Direction Dependence

A continuous silica film with well aligned mesochannels parallel to the Si(001) surface was found to be formed through sol–gel dip-coating of a silica precursor with nonionic ethylene oxide surfactant. Two two-dimensional mesoporous structures in centered and non-centered rectangular symmetries and with the short axes of elongated ellipsoidal pores normal to the surface were observed by X-ray and electron diffraction. Detailed transmission electron microscopy investigations were employed to view the direction dependence of the channel or pore packing in the continuous film.

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