Advanced Materials Research Vol. 1087

Abstract: Zeolite particles were synthesized through in-situ extraction of silica from rice husk ash without seeding method in the absence of organic template by a static hydrothermal condition at various duration for 8, 12, and 24h. The effect amorphous silica content on hydrothermal duration of synthesis products was evaluated with X-ray diffraction (XRD), and field emission microscopy (FESEM). The present of zeolite Y without seeding method via XRD analysis show a mixture of zeolite A, Y and P. The transformation of amorphous rice husk particle was increased gradually with the increased of hydrothermal reaction. The FESEM images showed agglomerated cubic-shaped morphology of the powders with increase in crystallization reaction. .

Abstract: TiO₂ nanotubes arrays were prepared by anodization of Ti in EG containing H₃PO₄ and NH₄F electrolyte. The samples were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy (EDX) and photoluminescence spectra (PL). The as-anodized TiO₂ nanotubes were annealed in inert (argon), reducing (nitrogen), or oxidizing (oxygen) atmosphere at 400 °C for 4 hr. XRD analysis revealed that the TiO₂ nanotubes were anatase after annealing. In this study, the TiO₂ nanotubes annealed in argon exhibited the highest degradation rate of methyl orange (MO) solution under ultraviolet irradiation among the samples. The degradation rate was approximately 98% after 5h, which may be ascribed to the large amount of oxygen vacancies and defects (phosphorus) within the Ar - TiO₂ sample that simultaneously increased the degradation rate of MO.

Abstract: Recycled glass from domestic waste also known as soda lime silica glass due to its main mineral composition is sodium oxide, calcium oxide and silica. The recycled glass was subjected to XRF in order to identify its chemical composition. Porous ceramic was made up of recycled glass powder added with ball clay and feldspar using ratio 90:5:5. Paper fiber was added as much as 5 wt% to act as foaming agent in the ceramic. Reaction of the ceramic body after sintering at three different temperatures in half an hour soaking time was studied using XRD spectroscopy.

Abstract: Elongated iron oxide nanopores (FNPs) were fabricated by anodisation of iron in fluoride-ethylene glycol (EG) added to it 1 ml, 1 M KOH electrolyte at three different voltages: 30 V, 40 V and 50 V. It was observed regardless of the voltage applied; the nanopores seem to be separated from one to another at the bottom part of the anodic film forming rather discreet nanotubular structure at this region. X-ray diffraction (XRD) was used to evaluate the phases present within the anodic layer. γ-FeOOH, Fe (OH)₂, and FeF₅.H₂O were detected in all samples. However, when the anodisation voltage was increased, peaks from the FeF₅.H₂O are more intense indicating either more F^- insertion in the anodic layer or crystallization of this phase at higher voltage. After annealing, XRD detected only hematite; α-Fe₂O₃ and magnetite; Fe₃O₄ indicative of phase formation or transformation had occurred during the annealing process. The annealed samples displayed an ability to adsorb Cr (VI) with almost 30 % reduction of the Cr (VI) concentration after 5 hours of exposure to the nanoporous anodic film.

Abstract: Barium zirconate titanate, BaZr_xTi_1-xO₃, (BZT) with x compositions have been widely studied as a potential candidate for antenna application. In this study, BZT film was prepared using the electrophoretic deposition (EPD) method. The EPD method was used to produce BZT composite into film for miniaturization purposes and dielectric properties improvement. The EPD process was performed with varying pH, voltages, deposition time and amount of Zr. The results showed that optimum deposition time was obtained at pH 4, 90V and 1 minute deposition time. Increasing Zr content decreased the dielectric constant of the BZT composite, and increased the loss tangent of the samples. The result is in agreement with microstructure observation that Zr addition in BZT decreased the grain size that suppressed the dielectric properties. This makes BZT is a suitable candidate for antenna application.

Abstract: This paper presents the synthesis of silica (SiO₂) from rice husk at different firing temperatures. Due to the environmental awareness and to reduce air pollution, agricultural wastes specifically rice husk is used to produce SiO₂. Silica was prepared by washing with clean water without any chemical treatment. The rice husk was fired at 700, 800, 900, 1000, 1100 and 1200°C. In order to determine the effect of firing rice husk at different temperature, X-ray Diffraction (XRD) analyses were conducted. Crystalline silica were obtained at 1100°C and 1200°C firing temperature. At 900°C and 1000°C firing temperature, silica was observed to be in a transitional phase of amorphous into crystalline or it called as semi crystalline. However, at 700°C and 800°C silica remains to be in amorphous phases.

Abstract: The present report aims to fabricate biphasic calcium phosphate (BCP) biocomposite in order to study the effects of sintering temperature on the sintered BCP biocomposite characteristics (phase’s formation, porosity and hardness properties). These effects were quantified using design of experiment (DOE) to develop mathematical models. BCP biocomposite pellets (60 wt% HA) were fabricated using mixing, pressing and sintered at two different temperatures (1100°C and 1250°C). The experiment was run by following the run order suggested by DOE software (Minitab 16) through randomization stage. Results show that sintering temperature will affect the formation of α-tricalcium phosphate (α-TCP) and the porosity of the samples. The formation of α-TCP phases will reduce the hardness value of BCP biocomposite.

Abstract: In this work, the effect of the milling speed on the properties of biodegradable Mg-1Mn alloy prepared by mechanical alloying was investigated. The magnesium-based alloy was prepared in solid state route using a high energy planetary mill. A mixture of pure magnesium and manganese powder was mechanically alloyed for 5 hours in argon atmosphere. Milling process was performed at various rotational speeds in order to investigate milling speed effect (i.e., 100, 200, 300 and 400 rpm) on phase formation and bulk properties. The as-milled powder was uniaxially compacted by cold pressing under 400 MPa at room temperature and sintered in argon atmosphere at 500 °C for an hour. X-ray diffraction analysis indicated that a single α-Mg phase was formed in magnesium matrix after sintering process. An increase in milling speed up to 300 rpm resulted in an increase in density and hardness of the binary alloy. The changes of bulk properties of the Mg-Mn alloys were correlated to the formation of solid solution phase and a reduction of porosity which led to an increasing in densification.

Abstract: The study was focused on the performance of rutile addition in the glaze for antibacterial application. Rutile powder in micro size (<5µm) (at different composition 5 wt%, 7 wt%, 9 wt%, 10 wt% and 15 wt%) were added in the glaze. Glazing was performed by dipping method for 10 seconds. Glazed tile was then sintered at 1200°C for 1 hour. Characterizations used to observe the properties of produced tiles were physical observation, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Optimum sample was undergone an antibacterial test towards E.coli.

Abstract: In this study, modification of aluminium silicon eutectic alloy by grain modifier, strontium was investigated on conventional and slope cast A356 alloy. A356 alloy with addition of 0 to 0.97 wt.% Sr was prepared by conventional and slope casting in melting furnace. The molten metal of A356 alloy was casted into steel mould. Microstructure was observed using SEM. Phase analysis was done using XRD. Microhardness was conducted using Vicker microhardness. Microstructure of conventional cast displayed dendritic structure whereas slope cast displayed globular structure. Addition of Sr refined eutectic structure in both conventional and slope cast alloy. Phase analysis revealed the presence of Al2Sr phase in conventional cast Al-6Si-0.97Sr. Microhardness of the conventional cast alloy decreased with increasing of Sr up to 0.97 wt.%.