scholarly journals Electrophoretic Deposition of Chitosan Films Doped with Nd2Ti2O7 Nanoparticles as Protective Coatings against Corrosion in Saline Solutions

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
M. Martinez-Gomez ◽  
A. Quinto-Hernandez ◽  
N. S. Flores-Garcia ◽  
Jan Mayén ◽  
M. Dominguez-Diaz ◽  
...  
Keyword(s):  
Electrophoretic Deposition ◽  
Moisture Absorption ◽  
Protective Coatings ◽  
Effective Area ◽  
Reduction Reaction ◽  
Absorption Capacity ◽  
X Ray Diffraction ◽  
Chitosan Films ◽  
Average Size ◽  
Saline Solutions

In this study, the electrophoretic deposition of chitosan films doped with Nd2Ti2O7 nanoparticles was carried out as corrosion protection systems for exposed materials in aqueous environments rich in chlorides. Completely crystalline Nd2Ti2O7 nanoparticles with an average size of 100-200 nm were obtained. Electrophoretic deposition of chitosan films with Nd2Ti2O7 nanoparticles was possible. With a working voltage of 5 V and 20 minutes of deposition, homogenous chitosan films with a thickness of 4 microns were obtained. According to the FT-IR (Fourier transform infrared spectroscopy), Raman, and XRD (X-ray diffraction) analyses, it was observed that the presence of the nanoparticles modified the properties of the chitosan films, that is, their crystallinity was increased and their moisture absorption capacity was reduced. These modifications caused a better performance against the corrosion of chitosan films deposited on 1018 carbon steel. Its electrochemical evaluation showed that the chitosan films perform as cathodic coatings by affecting the oxygen reduction reaction. This was possible due to the barrier effect of the Nd2Ti2O7 nanoparticles, by blocking the effective area for the diffusion of the aggressive electrolyte species.

Bacterial Cellulose as a Template for the Formation of Polymer/Nanoparticle Nanocomposite

2011 ◽  
Vol 2 (3) ◽  
Author(s):  
Cai Zhijiang ◽  
Hou Chengwei ◽  
Yang Guang ◽  
Kim Jaehwan
Keyword(s):  
Silver Nanoparticles ◽  
Bacterial Cellulose ◽  
Weight Percent ◽  
Preparation Condition ◽  
Reduction Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Agno3 Solution ◽  
Silver Nanocomposites ◽  
Average Size

In this paper, we investigate a novel method using bacterial cellulose (BC) as template by in situ method to prepare BC/silver nanocomposites. We first introduce sonication procedure during immersion and reduction reaction process to make sure that the silver nanoparticles can be formed and distributed homogeneously throughout the whole bacterial cellulose network. The BC/silver nanocomposites were confirmed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). To examine the effect of varying solution concentrations on silver nanoparticles formation, the concentration of AgNO3 solution was increased from 0.01 M to 0.05 M and Ag+-ions were reduced by the same concentration of NaBH4. The effects of time and frequency of sonication on BC/silver nanocomposite preparation were also investigated by varying sonication time from 10 min to 60 min and sonication frequency from 20 kHz to 60 kHz. Compared with an ordinary process, ultrasound seems to be an effective way for ions to penetrate into BC and thus the weight percent of silver nanoparticles can be increased. Combined with TGA result, the weight percent of silver nanoparticles can be improved from 8.9% to 31.7% with simple sonication procedure performed by the same preparation condition. However, the average size of silver nanoparticles is around 15 nm, which is bigger than ordinary process. This may be due to the aggregation of small nanoparticles, especially at high AgNO3 concentration.

In Vitro Assessment of Hydroxyapatite Coating on the Surface of Additive Manufactured Ti6Al4V Scaffolds

2016 ◽  
Vol 879 ◽  
pp. 2444-2449 ◽  
Author(s):  
Ekaterina Chudinova ◽  
Maria Surmeneva ◽  
Andrey Koptioug ◽  
Irina V. Savintseva ◽  
Irina Selezneva ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Human Mesenchymal Stem Cells ◽  
Nanocrystalline Structure ◽  
X Ray Diffraction ◽  
Ha Coating ◽  
Magnetron Sputter Deposition ◽  
In Vitro Assessment ◽  
Average Size

Custom orthopedic and dental implants may be fabricated by additive manufacturing (AM), for example using electron beam melting technology. This study is focused on the modification of the surface of Ti6Al4V alloy coin-like scaffolds fabricated via AM technology (EBM®) by radio frequency (RF) magnetron sputter deposition of hydroxyapatite (HA) coating. The scaffolds with HA coating were characterized by Scanning Electron microscopy, X-ray diffraction. HA coating showed a nanocrystalline structure with the crystallites of an average size of 32±9 nm. The ability of the surface to support adhesion and the proliferation of human mesenchymal stem cells was studied using biological short-term tests in vitro. In according to in vitro assessment, thin HA coating stimulated the attachment and proliferation of cells. Human mesenchymal stem cells cultured on the HA-coated scaffold also formed mineralized nodules.

In-situ stabilization of silver nanoparticles in polymer hydrogels for enhanced catalytic reduction of macro and micro pollutants

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Luqman Ali Shah ◽  
Rida Javed ◽  
Mohammad Siddiq ◽  
Iram BiBi ◽  
Ishrat Jamil ◽  
...  
Keyword(s):  
Catalytic Reduction ◽  
Thermo Gravimetric Analysis ◽  
Activation Parameters ◽  
Reduction Reaction ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
In Situ Stabilization ◽  
Hybrid Hydrogels ◽  
Kinetics Of

AbstractThe in-situ stabilization of Ag nanoparticles is carried out by the use of reducing agent and synthesized three different types of hydrogen (anionic, cationic, and neutral) template. The morphology, constitution and thermal stability of the synthesized pure and Ag-entrapped hybrid hydrogels were efficiently confirmed using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). The prepared hybrid hydrogels were used in the decolorization of methylene blue (MB) and azo dyes congo red (CR), methyl Orange (MO), and reduction of 4-nitrophenol (4-NP) and nitrobenzene (NB) by an electron donor NaBH4. The kinetics of the reduction reaction was also assessed to determine the activation parameters. The hybrid hydrogen catalysts were recovered by filtration and used continuously up to six times with 98% conversion of pollutants without substantial loss in catalytic activity. It was observed that these types of hydrogel systems can be used for the conversion of pollutants from waste water into useful products.

scholarly journals Chitosan as a Protective Matrix for the Squaraine Dye

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1171
Author(s):  
Halina Kaczmarek ◽  
Patryk Rybczyński ◽  
Piotr Maćczak ◽  
Aleksander Smolarkiewicz-Wyczachowski ◽  
Marta Ziegler-Borowska
Keyword(s):  
Solid State ◽  
Uv Radiation ◽  
Dye Degradation ◽  
Protective Coatings ◽  
Protective Action ◽  
High Energy ◽  
Modified Chitosan ◽  
Dye Release ◽  
Squaraine Dye ◽  
Chitosan Films

Chitosan was used as a protective matrix for the photosensitive dye-squaraine (2,4-bis[4-(dimethylamino)phenyl]cyclobutane-1,3-diol). The physicochemical properties of the obtained systems, both in solution and in a solid-state, were investigated. However, it was found that diluted chitosan solutions with a few percent additions of dye show an intense fluorescence, which is suppressed in the solid-state. This is related to the morphology of the heterogeneous modified chitosan films. The important advantage of using a biopolymer matrix is the prevention of dye degradation under the influence of high energy ultraviolet (UV) radiation while the dye presence improves the chitosan heat resistance. It is caused by mutual interactions between macromolecules and dye. Owing to the protective action of chitosan, the dye release in liquid medium is limited. Chitosan solutions with a few percent additions of squaraine can be used in biomedical imaging thanks to the ability to emit light, while chitosan films can be protective coatings resistant to high temperatures and UV radiation.

Evaluation of Si Coating on Ferritic Steels by CVD-FBR Technology in Steam Oxidation

2009 ◽  
Vol 289-292 ◽  
pp. 413-420 ◽  
Author(s):  
F.J. Bolívar ◽  
L. Sánchez ◽  
M.P. Hierro ◽  
F.J. Pérez
Keyword(s):  
Power Plants ◽  
Protective Coatings ◽  
Steam Oxidation ◽  
Steam Turbines ◽  
X Ray Diffraction ◽  
Steam Power ◽  
Factors Affecting ◽  
Steam Power Plants ◽  
Temperature And Pressure ◽  
Major Factors

The development of new power generation plants firing fossil fuel is aiming at achieving higher thermal efficiencies of the energy conversion process. The major factors affecting the efficiency of the conventional steam power plants are the temperature and, to a lesser extent, the pressure of the steam entering the turbine. The increased operating temperature and pressure require new materials that have major oxidation resistance. Due to this problem, in the last years numerous studies have been conducted in order to develop new coatings to enhance the resistance of steels with chromium contents between 9 and 12% wt against steam oxidation in order to allow operation of steam turbines at 650 0C. In this study, Si protective coatings were deposited by CVD-FBR on ferritic steel P-91. These type of coatings have shown to be protective at 650 0C under steam for at least 3000 hours of laboratory steam exposure under atmospheric pressure. Morphology and composition of coatings were characterized by different techniques, such as scanning electron microscopy (SEM), electron probe microanalysis, and X-ray diffraction (XRD). The results show a substantial increase of steam oxidation protection afforded by Si coating by CVD-FBR process.

Preparation and Characterisation of TiO2 Thick Films Fabricated by Electrophoretic Deposition

2007 ◽  
Vol 561-565 ◽  
pp. 2163-2166 ◽  
Author(s):  
H.Z. Abdullah ◽  
Charles C. Sorrell
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Growth ◽  
Electrophoretic Deposition ◽  
Defect Formation ◽  
Titanium Foil ◽  
X Ray Diffraction ◽  
Voltage Range ◽  
X Ray ◽  
Scanning Electron

Rutile nano-powders were suspended in a solution of acetylacetone and iodine. The suspensions were electrophoretically deposited on titanium foil at a voltage range of 5-30 V over times of 5-120 s. The dried tapes then were sintered at 800°C for 2 h in flowing argon. Both the green and fired tapes were examined by field emission scanning electron microscopy, optical microscopy, X-ray diffraction, and Raman microspectroscopy. The thickness of the films depended on the voltage and the time of deposition. The sintered microstructures depended significantly on the thickness of the film, which was a function the proximity to the Ti/TiO2 interface. The interface is critical to the microstructure because it acts as the source of defect formation, which enhances sintering, grain growth, and grain facetting.

Design of Alumina/Alumina Laminate Composites with Crystalline-Orientated Layers Produced by Electrophoretic Deposition under a High Magnetic Field

2006 ◽  
Vol 314 ◽  
pp. 25-32
Author(s):  
Tetsuo Uchikoshi ◽  
Tohru Suzuki ◽  
Hideo Okuyama ◽  
Yoshio Sakka
Keyword(s):  
Magnetic Field ◽  
Electrophoretic Deposition ◽  
Orientation Angle ◽  
Layer By Layer ◽  
Alumina Ceramics ◽  
X Ray Diffraction ◽  
Laminate Composites ◽  
Laminar Composites ◽  
The Magnetic Field ◽  
Oriented Layers

Highly crystalline-textured alumina ceramics were fabricated by electrophoretic deposition (EPD) in a strong magnetic field of 12 T. Preferred orientation of the bulk was controlled by changing the direction of the applied electric field E relative to the magnetic field B during the EPD. Average orientation angle of the prepared monoliths as a function of the angle between the vectors E and B, ϕ B-E was estimated from the X-ray diffraction analysis. Alumina/alumina laminar composites with crystalline- oriented layers were also fabricated by alternately changing the ϕ B-E layer by layer during EPD in a magnetic field of 12 T.

The effect of silver concentration and calcination temperature on structural and optical properties of ZnO:Ag nanoparticles

2015 ◽  
Vol 29 (01) ◽  
pp. 1450254 ◽  
Author(s):  
M. Shayani Rad ◽  
A. Kompany ◽  
A. Khorsand Zak ◽  
M. E. Abrishami
Keyword(s):  
Calcination Temperature ◽  
Sol Gel ◽  
Visible Emission ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Zno Nps ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Average Size

Pure and silver added zinc oxide nanoparticles ( ZnO -NPs and ZnO : Ag -NPs) were synthesized through a modified sol–gel method. The prepared samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. In the XRD patterns, silver diffracted peaks were also observed for the samples synthesized at different calcination temperatures of 500°C, 700°C, 900°C except 1100°C, in addition to ZnO . TEM images indicated that the average size of ZnO : Ag -NPs increases with the amount of Ag concentration. The PL spectra of the samples revealed that the increase of Ag concentration results in the increase of the visible emission intensity, whereas by increasing the calcination temperature the intensity of visible emission of the samples decreases.

Preparation of Silica-Supported Nickel Molybdenum Phosphides by Temperature-Programmed Reduction Technique

2007 ◽  
Vol 124-126 ◽  
pp. 1765-1768 ◽  
Author(s):  
So Yeon Lee ◽  
Yong Kul Lee ◽  
S.Ted Oyama ◽  
Seok Hee Lee ◽  
Hee Chul Woo
Keyword(s):  
Single Phase ◽  
Reduction Rate ◽  
Reduction Reaction ◽  
Molar Ratio ◽  
Infrared Spectrometry ◽  
Molybdenum Oxides ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
Ammonium Hydrogen ◽  
Temperature Programmed

Silica supported nickel molybdenum phosphides (NiMoP/SiO2) were successfully prepared by temperature-programmed reduction (TPR) reaction of phosphorous-impregnated nickel molybdenum oxides (NiMoO4) precursors with hydrogen at relatively low temperatures (530 – 590 oC) and characterized by Fourier transform-Infrared spectrometry (FT-IR), X-ray diffraction (XRD), Electron probe microanalysis (EPMA) and Temperature-programmed reduction reaction (TPR). The process of solid transformation and properties of materials prepared from ammonium hydrogen phosphate (AMP)-impregnated samples were compared with those of phosphide made from phosphoric acid (PAC)-impregnated samples. Results show that the formation of a single NiMoP phase on silica significantly depends on reduction rates, phosphorous sources and phosphorous loadings. A single phase of NiMoP on SiO2 was particularly promoted at a below 5 oC/min of reduction rate and the starting molar ratio of Ni/Mo/P=1/1/1. A single phase of crystalline NiMoP on silica was produced from AMP-impregnated samples, while other phases of MoP, Ni2P, or NiMoP2 were appeared from PAC-impregnated samples with loading. The new phase of NiMoP2 was occurred with increasing phosphorous loading (above Ni/Mo/P=1/1/2.5) as a result of facilitated contact on the surface between the Ni-Mo bimetallic component and the phosphorous reagent

scholarly journals Effects of CeO2 and Sb2O3 on the Nonlinear Photochemical Process in Ultrashort Laser Gaussian—Bessel Beams Irradiated Photo—Thermo—Refractive Glass

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 615
Author(s):  
Xu Wang ◽  
Guodong Zhang ◽  
Guangying Li ◽  
Rui Lou ◽  
Zhe Sun ◽  
...  
Keyword(s):  
Microfluidic Chips ◽  
X Ray Diffraction ◽  
Bessel Beams ◽  
Optical Elements ◽  
Photochemical Process ◽  
Co Doping ◽  
Fs Laser ◽  
Average Size ◽  
Electron Transfer Processes ◽  
Ultrashort Laser

Microfluidic chips and optical elements can be fabricated based on the nonlinear photosensitivity in photo–thermo–refractive (PTR) glass by controlling the growth of nanocrystals in the femtosecond (fs) laser–irradiated region. Here, we focus on CeO2 and Sb2O3 that play important roles in UV irradiation, experimentally investigate the effects of the dopants on the nonlinear photochemical process in PTR glass triggered by fs Gaussian–Bessel beams. The results show that the generation of Ag0 atoms and the Ag nanoparticles can be improved by CeO2 and Sb2O3 co–doping. Besides, each multivalent ion in PTR glass possibly participates in the electron transfer processes and contributes to the generation of Ag0 atoms. Finally, X–ray diffraction analysis reveals the precipitation of NaF nanocrystals with an average size of 10 to 12 nm after laser irradiation and thermal treatment, which is unrelated to the dopants.

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