scholarly journals Comprehensive study of the effect of hot-dipping process parameters on Sn-Sb coating properties for α-brass substrate

Author(s):  
Ali Barak ◽  
Morteza Tamizifar

This study's main purpose is to achieve an optimal hot-dip coating condition of Sn-Sb for an α-brass alloy. Therefore, the hot-dipping parameters, including pre-flux lubricants, immersion temperature, time, and withdrawal speed were investigated. ZnCl2 and SnCl2 were used as pre-flux bath additives. The temperature of the immersion bath was selected to be in the range of 250-300 °C. Also, the exposing time and withdrawal speed of the specimens during the hot-dipping process were in the range of 10-60 sec and 254-1524 mm/min, respectively. Visual inspection of the coating revealed that by using SnCl2 as a pre-flux additive, high-quality smooth coating is achieved. According to the AFM result, the initial roughness value of the substrate was 450 nm. The coating's roughness value with SnCl2 and SnCl2+ZnCl2 pre-fluxes were in the range of 300-500 and 700-900 nm, respectively. Therefore, ZnCl2 pre-flux is associated with a rougher surface. Corrosion test analysis revealed that both coating condition with different pre-fluxes leads to increasing corrosion resistance however better improvement in corrosion behavior is accomplished by smooth coating surface. The quantitative analysis of the polarization curve revealed that the corrosion rate of the smooth coating is decreased 7-12.5 times in comparison with the substrate. According to the SEM analysis, the predominant phases which were appeared at the interface of the coating and substrate were Cu3Sn and Cu6Sn5. SEM analysis revealed that the Cu3Sn intermetallic compound was this first phase, which was promoted near to the substrate vicinity during the hot-dipping process.

2017 ◽  
Vol 68 (5) ◽  
pp. 1077-1080
Author(s):  
Krisztina Martha ◽  
Alexandru Ogodescu ◽  
Cristina Ioana Bica ◽  
Cristina Molnar Varlam

Almost all orthodontic wires suffer from corrosion as they are intra-orally engaged. This chemical structure alteration appears on the surface of these wires, surface topography can be easily visualised with scanning electron microscope method. The aim of our study was to assess the intraoral corrosion of the retrieved orthodontic Ni-Ti archwires. Archwire retrieval procedure yielded approximately 30 retrieved wires, placed intra-orally for 1-5 months. SEM analysis was performed and surface changes were interpreted. Our SEM results showed, that surface corrosion and pitting can be seen on the surface of retrieved Ni-Ti wires, the depth of corrosion depends on the time wires have been engaged in the oral cavity. With regards of metal liberation consequently surface corrosion, practitioners should be avare of these chemical changes which can affect the resistence of the orthodontic appliance and patient health.


2019 ◽  
Vol 234 (10) ◽  
pp. 647-655
Author(s):  
Zohra Nazir Kayani ◽  
Atiqa Aslam ◽  
Rabia Ishaque ◽  
Syeda Nosheen Zahra ◽  
Hifza Hanif ◽  
...  

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.


2020 ◽  
Vol 978 ◽  
pp. 384-389
Author(s):  
Sritama Roy ◽  
Saswati Soumya Dash ◽  
Prasanna Kumar Sahu ◽  
Smita Mishra ◽  
Jyoti Prakash Kar

Zinc Oxide (ZnO) thin films were produced by the sol gel dip coating process on the p-type silicon substrate with various withdrawal speeds changing from 1 to 4 cm/min, respectively. The films were annealed at a temperature of 500 °C for an hour in air ambient. The thin film thickness was found to be raised with the rise in withdrawal speed. The uniform distribution of the grains was appeared for all the films. The evolution of c-axis oriented (002) peak was revealed from X-ray diffraction (XRD) studies. The microstructural and optical properties of ZnO films were investigated by Raman, FTIR and photoluminescence spectroscopy (PL). The resistive switching properties of ZnO based memristors were studied by performing the current-voltage (I-V) measurements, where the thin films coated with lower withdrawal speed, have shown better switching property with rapid rise and fall of current during SET and RESET process, respectively.


Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5701
Author(s):  
Joanna Olczyk ◽  
Jadwiga Sójka-Ledakowicz ◽  
Anetta Walawska ◽  
Anna Antecka ◽  
Katarzyna Siwińska-Ciesielczyk ◽  
...  

One of the directions of development in the textiles industry is the search for new technologies for producing modern multifunctional products. New solutions are sought to obtain materials that will protect humans against the harmful effects of the environment, including such factors as the activity of microorganisms and UV radiation. Products made of natural cellulose fibers are often used. In the case of this type of material, it is very important to perform appropriate pretreatment before subsequent technological processes. This treatment has the aim of removing impurities from the surface of the fibers, which results in the improvement of sorption properties and adhesion, leading directly to the better penetration of dyes and chemical modifiers into the structure of the materials. In this work, linen fabrics were subjected to a new, innovative treatment being a combination of bio-pretreatment using laccase from Cerrena unicolor and modification with CuO-SiO2 hybrid oxide microparticles by a dip-coating method. To compare the effect of alkaline or enzymatic pretreatment on the microstructure of the linen woven fabrics, SEM analysis was performed. The new textile products obtained after this combined process exhibit very good antimicrobial activity against Candida albicans, significant antibacterial activity against the Gram-negative Escherichia coli and the Gram-positive Staphylococcus aureus, as well as very good UV protection properties (ultraviolet protection factor (UPF) > 40). These innovative materials can be used especially for clothing or outdoor textiles for which resistance to microorganisms is required, as well as to protect people who are exposed to long-term, harmful effects of UV radiation.


Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3738 ◽  
Author(s):  
A. Smalenskaite ◽  
M. M. Kaba ◽  
I. Grigoraviciute-Puroniene ◽  
L. Mikoliunaite ◽  
A. Zarkov ◽  
...  

In this study, new synthetic approaches for the preparation of thin films of Mg-Al layered double hydroxides (LDHs) have been developed. The LDHs were fabricated by reconstruction of mixed-metal oxides (MMOs) in deionized water. The MMOs were obtained by calcination of the precursor gels. Thin films of sol–gel-derived Mg-Al LDHs were deposited on silicon and stainless-steel substrates using the dip-coating technique by a single dipping process, and the deposited film was dried before the new layer was added. Each layer in the preparation of the Mg-Al LDH multilayers was separately annealed at 70 °C or 300 °C in air. Fabricated Mg-Al LDH coatings were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and atomic force microscopy (AFM). It was discovered that the diffraction lines of Mg3Al LDH thin films are sharper and more intensive in the sample obtained on the silicon substrate, confirming a higher crystallinity of synthesized Mg3Al LDH. However, in both cases the single-phase crystalline Mg-Al LDHs have formed. To enhance the sol–gel processing, the viscosity of the precursor gel was increased by adding polyvinyl alcohol (PVA) solution. The LDH coatings could be used to protect different substrates from corrosion, as catalyst supports, and as drug-delivery systems in medicine.


2018 ◽  
Vol 7 (4.30) ◽  
pp. 538 ◽  
Author(s):  
Maytham Qabel Hamzah ◽  
Salim Oudah Mezan ◽  
Alaa Nihad Tuama ◽  
Abdullah Hasan Jabbar ◽  
Mohd Arif Agam

Synthetic polymer/TiO2 composite such as Polystyrene/TiO2 has become recent highly research materials due to its potential and significant application in various fields. we can tune the polymer and nanoparticles by different techniques such as change the materials concentration, Exposure of materials to laser radiation, Exposure of materials to laser radiation, especially in tuning the polystyrene/TiO2 composite energy band gap. In this review, several methods of preparation are briefly explored such as pan-milling, precipitation, melt compounding, dip-coating, solution cast, and sol-gel method. Some recent advancement that focuses on the two basic elements: polymer and TiO2 are also included especially discussing on photocatalytic degradation that introduces photon as manipulate parameter to tune the polymer/TiO2 composite energy band gap. Scanning electron microscope (SEM) analysis of various polymer/TiO2 (type n concentration) and Polystyrene/TiO2 (concentration and nanoparticles sizes) are the focus of the discussion before exposure to laser radiation as photodegradation source.   


2013 ◽  
Vol 683 ◽  
pp. 38-41
Author(s):  
Liu Xue Zhang ◽  
Hong Wu Xu ◽  
Xiu Lian Wang ◽  
Liang Zhao

The reactive polymer fiber with high adsorption capacity and good mechanical properties, RPF-AA, was prepared by the processes of pre-treatment, modification of the commercial PAN fiber. In order to improve the repeating circles of the semiconductor titania photocatalyst and broaden its applications, fine titania particles immobilized in RPF-AA fibers (TiO2/RPF-AA) were prepared successfully at room temperature by a dip-coating method. Tetrabutyl orthotitanate (TBOT) was hydrolyzed in presence of hydrolysis control agent tetrabutylammonium hydroxide (TBA)OH and the TiO2 fine particles were crystallized under microwave (MW) irradiation. The X-ray diffraction (XRD) analyses indicated that the fine particles obtained with MW irradiation have much higher crystallinity with a single phase anatase compared with the non-MW-treated solution. The continuous layers of titania were found on RPF-AA fibers by the scanning electron microscopy (SEM) analysis. The fibers with anatase coatings showed high photocatalytic property and better repetition on the photodegradation of MB. The coated fibers were scattered on the water surface and the catalytic reaction proceeded. After completion the decomposition process, the coated fibers were easily recovered using a filter.


2014 ◽  
Vol 597 ◽  
pp. 165-169
Author(s):  
Jie Hong Lei ◽  
Ri Dong Zhang

The porous sol-gel silica thin films were prepared on silicon substrate by the dip coating process. The surface roughness and microstructure of the film was measured by optical microscopy and AFM .Coating thickness and refractive index were measured by ellipsometry method. Influence of withdrawal speed and concentration of colloid was investigated for the thickness of silica. The relation of the thickness and withdrawal speed was fitted by the linear and power functions, and the results were analyzed and compared. It was found that the films with the same thickness prepared by different concentrations of colloid have different refractive indexes. The experimental results indicated that the thickness and refractive index of the film can be controlled by changing the withdrawal speed and colloid concentration.


Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2273
Author(s):  
Farah Eryssa Khalid ◽  
Siti Aqlima Ahmad ◽  
Nur Nadhirah Zakaria ◽  
Noor Azmi Shaharuddin ◽  
Suriana Sabri ◽  
...  

Imperata cylindrica, often known as cogon grass, is a low-cost and useful sorbent for absorbing oil and optimising processes. The effects of temperature, time, packing density and oil concentration on oil absorption efficiency were investigated and optimised utilising one-factor-at-a-time (OFAT) and response surface methodology (RSM) approaches. Temperature and oil concentration are two important variables in the oil absorption process. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis were used to characterise cogon grass. After treatment and oil absorption, the FTIR method indicated new formation and deformation of functional groups, while SEM revealed changes in the surface and texture of cogon grass, including a roughened and jagged surface. Validation of the RSM model yielded 93.54% efficiency with 22.45 mL oil absorbed at 128 °C temperature and 36 (v/v)% oil concentration while keeping packing density and time constant at 30 min and 0.20 g/cm3, respectively. This study may provide an insight into the usefulness of a statistical approach to maximise the oil absorption of cogon grass as an oil sorbent.


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