scholarly journals Sol-gel derived coatings for the conservation of steel

2015 ◽  
Vol 9 (2) ◽  
pp. 81-89 ◽  
Author(s):  
Erika Kiele ◽  
Jurate Senvaitiene ◽  
Asta Grigucevicienė ◽  
Rimantas Ramanauskas ◽  
Rimantas Raudonis ◽  
...  

In this paper, sol-gel processing route has been applied and investigated for the conservation of steel. Nanosilica coatings on steel surface have been prepared using tetraethylorthosilicate (TEOS) as a starting material. The methyl-modified silica sols were obtained by mixing of 3mas.% SiO2 sol solution with hexamethyldisilozane (HMDS). The surface of steel was coated by dip-coating technique. In order to compare the characteristics of coatings, the steel substrates were also coated with commercial polymers Paraloid B67, Cosmolloid H80 and Antik Patina. The surface morphology changes of the uncoated and coated specimens before and after photochemical ageing were investigated by scanning electron microscopy and atomic force microscopy. The structure of the prepared coatings was also investigated by FTIR spectroscopy. The hydrophobicity of surfaces was evaluated by contact angle measurements. Potentiodynamic measurements were obtained in order to compare corrosion parameters of the coatings.

1970 ◽  
Vol 17 (2) ◽  
pp. 191-196
Author(s):  
Artūras ŽALGA ◽  
Brigita ABAKEVIČIENĖ ◽  
Aleksej ŽARKOV ◽  
Aldona BEGANSKIENĖ ◽  
Aivaras KAREIVA ◽  
...  

The synthesis of nanostructured films of 20 mol% Y2O3 stabilized ZrO2 on corundum (Al2O3) substrates was performed from different sols using dip-coating technique. All obtained samples were repeatedly annealed at 800 °C temperature after each dipping procedure and fully characterized by X-ray diffraction (XRD) analysis. XRD data exhibited that at 800 °C temperature nano-sized Y0.2Zr0.8O2 thin films with cubic (Fm-3m) crystal structure have been formed. The morphological features of obtained coatings were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface tension and hydrophility of the synthesized films were determined by contact angle measurements (CAM).http://dx.doi.org/10.5755/j01.ms.17.2.491


2019 ◽  
Vol 25 (4) ◽  
pp. 365-368
Author(s):  
Pranas USINSKAS ◽  
Živilė STANKEVIČIŪTĖ ◽  
Gediminas NIAURA ◽  
Justinas ČEPONKUS ◽  
Aivaras KAREIVA

In this study we demonstrate, that sol–gel route is suitable to quicker obtain calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp) coatings on crystalline Si substrate by modified dip-coating technique. The substrate was dip-coated by precursor and dried for 10 minutes at 200 °C with following cooling using the heating block for 110 min and annealing at 650 °C. Ethylendiamintetraacetic acid and 1,2-ethandiol, and triethanolamine and polyvinyl alcohol were used as complexing agents and as gel network forming agents, respectively. The obtained coatings were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), FTIR spectroscopy and contact angle measurements (CAM).


2014 ◽  
Vol 91 ◽  
pp. 13-18 ◽  
Author(s):  
A. Prichodko ◽  
V. Jonauske ◽  
M. Cepenko ◽  
A. Beganskiene ◽  
A. Kareiva

Calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp), tricalcium phosphate (Ca3(PO4)2, TCP) and calcium oxide (CaO) are the main components of inorganic part of human bones. Such synthetic nanocomposites could be very important implantable materials and using as substitute material for human hard tissues (bones and teeth). In this study, an aqueous sol-gel chemistry route has been developed to prepare nanostructured CHAp thin films on stainless steel substrate. For the preparation of thin films dip-coating and spin-coating techniques were used. The final samples were obtained by calcination of coatings for different time at 1000 °C. For the characterization of surface properties, the X-ray powder diffraction (XRD) analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM) and the contact angle measurements were recorded.


2015 ◽  
Vol 1109 ◽  
pp. 148-152
Author(s):  
A.K.M. Muaz ◽  
U. Hashim ◽  
Sharipah Nadzirah ◽  
M. Wesam Al-Mufti ◽  
Fatimah Ibrahim ◽  
...  

In the present research, nanocrystalline TiO2thin films have been prepared via a sol-gel method using Ti {OCH(CH3)2}4act as a precursor. The morphological effect of sets of as-deposited and annealed samples (100, 300, 500 and 700°C for 1 hour) and thickness variation on the structural properties were investigated by Atomic Force Microscopy (AFM) measurements. The observation showed that the size of grain increases with film thickness, indicating that the size of the particles in the films can be effectively controlled by changing the temperature of thermal treatment. AFM topology images of the as-deposited and annealed TiO2films at 100 and 300°C indicates the films are rather smooth, compact, bulky, not uniform and column-like structure. TiO2thin films annealed at 500 and 700°C showed homogenous morphology surface with regular size of spherical particles.


1990 ◽  
Vol 180 ◽  
Author(s):  
D.S. Kenzer ◽  
M.R. Teepe ◽  
G.A. Moore ◽  
G. Kordas

ABSTRACTYttrium methoxyethoxide, barium methoxyethoxide and various copper(II) alkoxide groups were used as precursors for the formation of YBa2Cu3O7-δ stable sols in a 2- methoxyethanol / methyl ethyl ketone / toluene / diisopropyl ketone solvent system. Sol fractal dimensions were varied with the sol concentration and with the addition of pyridine. Strong correlation was found between the wettability and the fractal dimensions of the various precursors as determined by contact angle measurements. YBa2Cu3O7-δ thin films were deposited on sapphire substrates using a dip-coating technique. The films were fired at 850°C under flowing oxygen or an ozone/oxygen mixture. Although the ozonetreatments helped in the formation of single YBa2Cu3O7-δ phase, they contributed to extensive cracking in the films. The different copper(II) alkoxide precursors had little effect on final film microstructure.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1554
Author(s):  
Justinas Januskevicius ◽  
Zivile Stankeviciute ◽  
Dalis Baltrunas ◽  
Kęstutis Mažeika ◽  
Aldona Beganskiene ◽  
...  

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.


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 243
Author(s):  
Diana Horkavcová ◽  
Quentin Doubet ◽  
Gisèle Laure Lecomte-Nana ◽  
Eva Jablonská ◽  
Aleš Helebrant

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.


2013 ◽  
Vol 741 ◽  
pp. 67-72 ◽  
Author(s):  
Gheorghe I. Gheorghe ◽  
Liliana Laura Badita

Total hip prosthesis (THP) is the most success of the 20th century in orthopaedic biomedical engineering. However due to difficult conditions within the human body its durability is generally limited to 15-16 years. THP is a bio-tribosystem, on which many mechanical, thermal, chemical and biological factors act. This paper presents the results of an analysis regarding the topography and tribological parameters of femoral heads structures before and after TiN coating. We report on the synthesis of TiN thin films on steel substrates by pulsed laser deposition (PLD) method for improving the mechanical characteristics of the structures. Adhesion resistance of the coating on the sub-layer was evaluated by scratching tests accompanied by Optical Microscopy (OM), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). As a principal result, this work points out that TiN protective coatings deposited by PLD technique with the maximum number of pulses can represent an alternative technology to ensure adhesion and scratch resistance of TiN coatings on femoral heads.


2007 ◽  
Vol 336-338 ◽  
pp. 593-596
Author(s):  
Chun Yang ◽  
Jun Ying Zhang ◽  
Hai Bing Feng ◽  
Wei Chang Hao ◽  
Tian Min Wang

Y2O3:Eu3+ thin film was synthesized by sol-gel method with inorganic salt raw materials, and the crystal structure and luminescent properties were investigated. By adding organic additive to the sol, a homogeneous film with high luminescent intensity could be obtained by dip-coating technique on the surface of alumina sheet and quartz glass. Structures of the films were studied by XRD and SEM. The excitation spectra of the films showed a wide excitation peak from 200nm to 260nm, and the emission spectra had a strongest emission peak at 611nm which revealed a close relationship with the calcining temperature.


Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 434 ◽  
Author(s):  
Ángel de Jesús Morales-Ramírez ◽  
Margarita García-Hernández ◽  
Dulce Yolotzin Medina-Velázquez ◽  
María del Rosario Ruiz-Guerrero ◽  
Fernando Juárez-López ◽  
...  

The effect of the polyvinylpyrrolidone (PVP, MW = 130,000) molar content, PVP/Lu = 1, 2.5, 4 and 5; on the photoluminescent and structural properties of sol-gel derived Lu2O3:Eu3+, Bi3+ has been analyzed. Thin hybrid films were deposited by means of the dip-coating technique on silica quartz substrates. Films deposited at 700 °C presented a cubic structure, with non-preferential orientation, even with the presence of PVP. The photoluminescence (PL) spectrum and Comission Internationale de l’Éclairage (CIE) chromaticity diagram of films revealed a reddish Eu3+ emission at 612 nm (5D0 →7F2) with an excitation at 320 nm of the Bi ions (6s2→6s6p), showing a highly-effective energy transfer process form Bi3+ to Eu3+ luminescent centers. On the other hand, the color temperature of the samples is strongly dependent on the PVP content, as a consequence of the observed difference on the branching ratios of 5D0 →7FJ transitions of europium ions. Lifetime studies present two different behaviors for the thin films: A non-exponential nature for the lower PVP contents, and a simple exponential nature for the highest PVP one, showing that the PVP tends to promote a better dissolution of segregates and, therefore, increases the lifetime of the Eu3+ emission.


Sign in / Sign up

Export Citation Format

Share Document