Papers by Keyword: Nanopowder

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Authors: K. Oleg, D. Edgar, S. Vitaly, P. Yury
Authors: Frida Ulfah Ermawati, Suasmoro Suasmoro, Suminar Pratapa
Abstract: A study of liquid mixing route to synthesize high purity Mg0.8Zn0.2TiO3 nanopowder, a candidate dielectric ceramics, has been successfully performed. Formation of the phases on the dried powder was studied using TG/DTA, XRD and FT-IR data. Rietveld analysis on the collected XRD patterns confirmed the formation of solid solution in the system. Such solid solution can be obtained from the powder calcined at 500 °C, but calcination at 550 °C gave rise to the most optimum molar purity up to 98.5% without intermediate phases. The role of Zn ions on the formation of solid solution was also discussed. Homogeneity of particle size distribution and nano-crystallinity of the system was verified from the particle size analyzer data, TEM image and the Rietveld analysis output.
Authors: Tien Li Chen, Ho Chang, Wei Hao Wong
Abstract: This study adds nanopowder, such as ZnO and TiO2, in different concentrations to water-based woodenware coating, and explores the properties of the coating on the woodenwares. After the coating has been applied to the testing materials, the thickness and lightness are measured. These values are compared to the properties of the water-based woodenware coating with nanopowder of specific concentration, such as hardness, lightness and adhesion. According to the results of the experiments, adding TiO2 nanopowder to the AE-418 water-soluble polyurethane coating helps to increase the hardness of the coating. The amount added is positively related to the hardness of the coating; the result is the opposite with the WP-1715 water-soluble acrylic resin coating. After adding powder such as TiO2 or ZnO to the AE-418 water-soluble polyurethane coating, the lightness of the coating becomes lower. However, powder with higher concentration leads to higher lightness. In addition, the adhesion of the coating is stronger when nanopowder of higher concentration is added.
Authors: Mi Young Park, Ho Ha, Won Baek Kim, Je Shin Park, Chang Youl Suh, Saet Byul Woo
Abstract: Non-evaporable getters (NEGs) are characterized by two major properties i.e. the activation and gas sorption rate for specific gases. Most of the commercial getters are alloys composed of micron-size powders. There have been speculations on the advantage of using nanosize powders as getter material for the obvious increase in volume to surface area ratio and for effective reaction with gases on size reduced particles. In this study, titanium powders of about 80 nm were prepared by electrical wire explosion method and their gettering properties were measured in accordance to ASTM standard. The activation of nano-size titanium powders was completed at about 450oC and the sorption rate was over 4 times higher than those of the micron-size titanium powders.
Authors: Rainer Gadow, Andreas Killinger, Andreas Rempp, Andrei Manzat
Abstract: Protective and functional coatings featuring outstanding tribological performance are of general interest for all kinds of industrial applications i.e for high performance automotive and mechanical applications. Thermal spray coating technologies play a key role in fabricating hard layers based on ceramic, metal - ceramic and further multiphase materials. Additional functionality can be achieved by combining these coatings with polymer based top coats with low friction coefficient or anti adhesive behaviour. Combined coatings feature also designed thermophysical and electrophysical properties. Several case studies will be discussed, ranging from automotive applications to paper and printing industry. Thermally sprayed coatings were applied using APS, HVOF and the newly developed HVSFS processes (High Velocity Suspension Spraying) with a special focus on nanoceramic feedstocks. In some applications polymer top coats with dispersed solid phases are applied to enhance functional properties. Special aspects in manufacturing engineering are addressed with particular importance not only of the influence of spray process parameters on coating properties but also of spray torch kinematic and robot trajectories on hardness, residual stress distributions, dimensional tolerances and porosity distributions will be discussed.
Authors: Ioana Cosmoiu, Dragoş Alexandru Apostol, Dan Mihai Constantinescu, Catalin R. Picu, Marin Sandu
Abstract: Epoxy-based nanocomposites with multi-wall carbon nanotubes (MWNT) and nanopowders were fabricated and subjected to monotonic uniaxial testing. Three procedures used to fabricate these nanocomposites are presented, as the dispersion of the MWNTs and nanopowders in the epoxy matrix is a significant challenge. Optical microscopy is used to observe the degree of mixing of the nanofillers in the resin. The inclusion of MWNT and nanopowders don't affect significantly the static properties, but lead to a slight increase of the strength and stiffness of the nanocomposite relative to the neat epoxy.
Authors: Nikita Martyushev
Abstract: This paper reports on the use of nanopowders in the coating composition forms in casting blanks from lead bronzes for the petrochemical industry. Influence of composition of used protective separating coating of casting mold on the microstructure castings was investigated. For experimental investigations following coating were selected [1]: the mixture of zirconium dioxide nanopowder with industrial oil and the same composition as it’s, but on the basis of aluminum oxide nanopowder. As the test material multicomponent and lead bronzes were selected. The cooling curves castings using coatings of different compositions by means the developed device thermograph were constructed using techniques developed by the authors. The study results showed that the greatest reduction in the cooling rate at the time of crystallization bronze corresponds to coating casting mold based on powder of zirconium dioxide (45 °C/c). The cooling rate is reduced only to 65 °C/c when coating based on aluminum oxide. Decrease the cooling rate of castings using these coatings can change the shape and size of lead inclusions and align the casting structure in section. Form inclusions lead is becoming more spherical and their interfacial surface is leveled. The greatest changes occur in the surface layers of castings. Is shown that the multicomponent bronzes decreased speed the cooling due to the use plasters leads not only to changes in the morphology of inclusions but also to lead the change in the phase composition. Decrease of cooling rate leads to increasing the amount of eutectoid and growth of hardness casting.
Authors: Anita Müller, François Ténégal, Xavier Armand, Frank Berger, Romuald Dez, Nathalie Herlin-Boime, Joachim Bill
Authors: Thanawat Klaytae, Sarawut Thountom
Abstract: A sol-gel combustion method has been effectively used to prepare SrTiO3 nanopowders. The effect of chitosan solution content addition in sol-gel combustion method on microstructure and morphology of SrTiO3 powders was investigated by XRD and SEM. It was demonstrated that the addition of chitosan solution is beneficial to the homogenously distributed in powder products. The particle sizes of powders were found that they were a large amount of agglomerated with the structure feature of nearly spherical in shape and consisted of nano-sized crystallites, which indicated by SEM.
Authors: M.Z. Borhan, R. Ahmad, Mohamad Rusop, Saifollah Abdullah
Abstract: Arsenic (As), Cadmium (Cd) and Lead (Pb) are the heavy metal and categorized as high toxicity compound. This element can be found in the animal and plant from bio accumulation mechanism. This bio accumulation will lead to the toxicity when its concentration surpasses regulated value. Centella asiatica is a plant belonging to the Umbelliferae family, hydrocotyle order, which has been used for curing of venous ulcers and venous hypertension for its activity on connective tissue metabolism and endothelial integrity. This plant also widely used in formulation of drugs and cosmetic. In order to produce high quality herbal product, the characterization and standardization of heavy metal content using modern technique must be carried out. Centella asiatica nanopowders were produced at different grinding condition and analyzed for As content using ICP-OES (Optima 7300 DV, Perkin Elmer). The confirmations of size were carried out using nanoZeta Sizer S (Malvern Instrument) and Field Emission Scanning Electron Microscope. The results obtained show that As, Cd and Pb presence in all type of grinding below the acceptable daily intake by the world health organization (WHO).
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