Advanced Materials Research Vol. 1087

Abstract: Nanocrystalline hydroxyapatite (HA) powder was synthesized by a simple heating process involving simple chemical reaction. The characterization of the produced powder showed that the powder is nanosize with particle in the range of 30-70 mm in diameter and almost evenly spherical in shape. The powder also has a high surface area of 43.16 m2/g. Field Emission Scanning Electron Microscopy (FESEM) observation showed the crystallite and particle size become bigger with an increment of calcination temperature, indicating increasing of crystallinity.. FESEM observation showed the particle size become bigger with an increment of calcinations temperature. It is in agreement with the crystallite size analysis, obtained by Scherer’s formula and particle size analysis, measured by nanoSizer. X-ray Diffraction (XRD) and Fourier Transform Infra Red Spectroscopy (FTIR) analyses exhibited the same result, where HA phase was clearly observed at at various temperatures up to 600 ̊C. However, at temperature more than 600 ̊C, Tri calcium phosphate (TCP) phase appeared suppressing the HA phase, producing biphasic calcium phosphate.

Abstract: ALD is a precision growth technique that can deposit either amorphous or polycrystalline thin films on a variety of substrates. The difference in substrate can cause a variation in the ALD process, even it is carried out using the same reactants and deposition conditions [1]. TiO₂ thin films were grown using TTIP (Titanium isopropoxide) ALD on silicon wafers, glass slides, and stainless steel plates in order to study the effect of substrates on the growth of TiO₂ with 3,000 deposition cycles, at 300°C.The thin films were analyzed using Xray Diffraction (XRD), Raman Spectroscopy, Atomic Force Microscope (AFM) and Spectroscopic Ellipsometer. From XRD analysis were indicates the main peak for anatase (101) (2θ= 25.3) was observed from the XRD patterns for TiO₂ on all substrates. The results show that crystalline TiO₂ thin films can easily grow on a crystal substrate rather than on an amorphous substrate.

Abstract: Hydroxyapatite, (HAp), Ca₁₀(PO4)₆(OH)₂, is recognised as biomaterial that widely used for orthopedics due to its similar to the inorganic component of human bone and enamel .The elements of HAp are primarily calcium and phosphorous, with a stoichiometric calcium to phosphorous ratio of 1.67 capable of promoting bone growth. Enormous amounts of by-product wastes from fishery factory lead to generating an undesirable environmental impact. Thus, this study was conducted to obtain biological natural HAp extracted from tilapia fish bones from fishery factory. Therefore, fish bone can be as cheap resource to produce HAp and crucial contributions in medical application. The fish bones of tilapia were boiled at 100°C to remove adhere meat and other impurities. Later, were milled for 1 h to form fine powder. The powder was calcined at temperature of 800° C and 1000° C for 3h respectively. The XRD result revealed the presence derived HAp and coherent with Joint Committee on Powder Diffraction Powder Standard data and the Thermo Gravimetric Analysis was carried out to show the thermal stability of the HAp powder. SEM results shown hexagonal particle sHApe obtained from HAp powder. The findings present a promising future regarded on producing high added value product such as hydroxyapatite (Ca/P ratio 1.757) from fishery wastes beneficial to medical application.

Abstract: The cerium-substituted yttrium-iron garnet (Ce-YIG) in Ce_xY_3–xFe₅O₁₂ is considered as a promising material for applications in high frequency wireless communication technology. In this work, we reported the structural properties of Ce-YIG. This material was produced via conventional solid state reaction (CSSR) with various molar ratio of cerium (x = 0.0, 0.1, 0.5, 1.0, and 1.5, respectively). A heat treatment was at a temperature of 1420 °C for 6 h after pre-fired at 1100 °C for 6 h. Multiple phases were presented in Ce-YIG ceramics. It was found, at x=1.5, the substitution of Ce into YIG has reached the solid solution limit. It was seen that, the peaks were shifted to the lower angle and proportional to the amount of Ce added. Thus, it can be concluded that, the substitution of Ce into YIG was successfully at x=0.1,0.5, and 1.0 respectively before reaching the solid solution limit at x=1.5.

Abstract: This study investigated the effect of Ni addition on intermetallic formation in the Sn-8Zn-3Bi solder under liquid state aging. The intermetallic compounds were formed by reacting the solder alloy with copper substrate. Different reflow time was used at temperature 220°C. Morphology of the phases formed was observed using scanning electron microscope (SEM) and in order to determine elemental compositions of the phases, energy dispersive x-ray (EDX) was used. The formation of the reaction layer led by Cu₅Zn₈ intermetallic and then followed by Cu₆Sn₅ and Cu₃Sn when reflow time increases. Keywords: lead free solder, intermetallic, Cu₅Zn₈, Cu₆Sn₅, liquid state aging.

Abstract: The properties of Pb(Zr_0.52Ti_0.48)O₃ (PZT) ceramics have been studied. PZT ceramic powders were successfully prepared by high planetary ball mill method under different milling time and then were sintered at different sintering temperature. The raw materials of PbO, ZrO₂ and TiO₂, powders were ball milled at 40 and 60 hours using high planetary mill. The mixing powders then were compacted and sintered at 950°C and 1200°C. Formations of the perovskite phase along with some secondary phase were seen after 40 and 60 hours of milling while single phase formation of PZT was seen after sintered at both sintering temperatures. The grain size of the samples becomes larger with the increasing temperature. In dielectric properties analysis, the dielectric constants were reduced due to increasing sintering temperature. Meanwhile, the loss tangents increased with sintering temperature.

Abstract: Lead Zirconate Titanate (PZT) ceramics are of great technological interest because of their excellent piezoelectric and ferroelectric properties. In this research, an effort will be made to enhance the PZT properties by doping with other elements. The objective of this research is to enhance the dielectric, hence increase the efficiency and performance of piezofan. Properties that piezoelectric fan should have are high mechanical piezoelectric coupling factor, high dielectric constant, easily polarized and high piezoelectric charge constant. Soft and isovalent dopant was a very suitable candidate to fulfill this requirement. The samples will be prepared via high planetary mill and use optimum compaction pressure due to these processes can skip calcinations process, which can reduce a lot of cost. This process also can avoid PbO loss during firing process. The proposed elements are isovalent dopant which is Sr²⁺ and donor dopant which is La³⁺ to subtitude Pb²⁺ at the A-site of PZT. Dopant is beneficial to the enhancement of physical properties of PZT – based ceramics. It also effectively improved the dielectric properties of PZT ceramics due to the effect of average grain size.

Abstract: Cathode-carbonate is a prospective material for low-temperature solid oxide fuel cells (LT-SOFCs). The influence of carbonate on the properties of cathode LT-SOFCs was studied. Different amounts of binary carbonate (Li₂CO₃:Na₂CO₃) were prepared at molar ratios of 67:33 and 62:38. The cathode composite powders were calcined at 750 °C for 2 h before uniaxial press. X-ray diffraction results confirmed that the carbonate in cathode composite existed as amorphous phase. Therefore, carbonate has a good compatibility with cathode composite powders. High-energy ball milling maintained the composite cathode powders at the nanoscale. The developed cathode composite also gave acceptable porosity values between 26% and 27%. The findings show that that the amount of binary (Li/Na) carbonate in cathode composite influences its properties, indicating potential for LT-SOFCs applications.

Abstract: Titanium dioxide (TiO₂) nanoarchitecture has been widely used in the environmental and energy related applications. Herein, a simple and facile synthesis method will be introduced for high-conversion preparation of TiO₂ nanotubes using hydrothermal method from nanoscale TiO₂ particles. The quantity of TiO₂ nanoparticles being used towards the formation of nanotubes was investigated using FESEM, TEM and EDX. In the present study, TiO₂ nanoparticles were treated chemically with NaOH aqueous solution and subsequently with HCl aqueous solution under optimum experimental condition. It was found that the TiO₂ nanotubes with outer diameter of 10 nm were successfully formed. In this case, the amount of residual Na⁺ ions during the hydrothermal synthesis stage can be controlled by HCl treatment, which resulted in the formation of one-dimensional TiO₂ nanotubes.

Abstract: Titania (TiO₂) nanotubes were successfully synthesized via a facile hydrothermal method. The influence of starting material (TiO₂ nanoparticles) content on the conversion of tubular structure during hydrothermal treatment was investigated. Based on the result obtained, it was found minimum 1 g of TiO₂ nanoparticles was required for completing the transformation of nanotubular structure. The photocatalytic activity of TiO₂ nanotubes was evaluated by degradation of organic methyl orange (MO) dye. Interestingly, one-dimensional TiO₂ nanotubes exhibited high photocatalytic oxidation rate (78% degradation) under UV irradiation for 5 hours. The reason was attributed to the high active surface area to generate more hydroxyl radicals (∙OH) for triggering photocatalytic oxidation reactions on the inner and outer surface of TiO₂ nanotubular structure.