Advanced Materials Research Vol. 620

Abstract: In this work, 20 % Pr doped bismuth sodium titanate (PBNT) powders were synthesized using the soft combustion technique. Three combustion agents; polyethylene glycol 200, citric acid and glycine with 0.2, 2.0 and 5.0 mol were used to aid combustion process. A single phase PBNT was obtained with the addition of 5 mol % citric acid. For most compounds, secondary phases presence such as Bi₄Ti₃O₁₂ and Bi₂Ti₂O₇. In general, crystallite size increased with increasing sintering temperature that was due to diffusion of ions at high temperature. Dielectric properties increased with increasing densities. The optimum properties were obtained for PBNT synthesized using 5 mol % citric acid sintered at 1100°C for 3 hours which gave the highest dielectric constant (1153.20), acceptable loss tangent (0.1074) and high relative density (95.03).

Abstract: The purpose of this research is to study the effect of synthesis temperature in order to produce anatase TiO₂ nanoparticles (NPs) without using strong acids. In this research TiO₂ nanoparticles was prepared by the hydrolysis and condensation of titanium (IV) isopropoxide in water at synthesis temperature of 0°C ± 0.1°C which produced anatase TiO₂ crystallite size of 4.66 nm. XRD (X-ray diffraction) was used to analyse the crystal structure of the TiO₂ and to calculate the crystallite size of the TiO₂ nanoparticles. Transmission electron microscope (TEM) was also used to characterise the morphology of the TiO₂ nanoparticles.

Abstract: Cu-Al intermetallic compound (IMC) in Cu wire-Al bond pad interconnect interface is drawing attention of researches. However, due to thin IMC thickness, the characterizations of the IMC are limited to expensive and time consuming techniques. An evaluation is performed to use common X-Ray Diffraction (XRD) technique to identify the IMC in the Cu wired micro-chip samples in powder form. Existence of mixture of CuAl and CuAl₂ was first confirmed by transmission electron microscope (TEM) and energy dispersive X-ray (EDX). In XRD analysis, peak correspond to CuAl phase is identified from measurement with slower scan configuration. The difficulty for IMC peak detection in diffractogram is due to low composition ratio of IMC relative to other materials available in the sample. KOH treatment for enhancing IMC peaks intensity does not work as expected as it etches the IMC as well.

Abstract: We report on the effect of the tungsten (W) cathode in controlling the morphology and properties of titanium (Ti) anodic oxide layer via an electrochemical anodization process. The content of ammonium fluoride (NH₄F) was varied in ethylene glycol (EG) electrolyte containing hydrogen peroxide (H₂O₂) in order to obtained the high ordered nanotubular structure. When amount of NH₄F was upto 5 wt%, highly ordered WO₃-TiO₂ nanotubes structure was observed. If insufficient amount of NH₄F is applied, the nanoporous structure will be favored. Highly ordered WO₃-TiO₂ nanotubes structure exhibited higher photocurrent density ( 0.9 mA/cm²) as compared to the WO₃-TiO₂ nanoporous structure.

Abstract: This work details the characterization of anatase nanoTiO₂ particles synthesized from Malaysian mineral precursors using the XRD and EDXRF. The properties that were analyzed were its crystallite sizes, relative crystallinity, phases, and chemical composition. It was determined that the crystallite size was quite small (15.6 nm), although the crystallinity of the sample is relatively low. The anatase phase seems to be dominant (100%), although in some cases when the processing parameters were changed or heat treatment were conducted, the existence of rutile is detected. The chemical composition showed that TiO₂ is the majority compound in the sample (~96%), although some metallic and non-metallic impurities are present (Zr, Nb, and S). It is concluded that Malaysian mineral precursors are capable of producing relatively high quality nanoTiO₂.

Abstract: Among the various characterization techniques, X-ray diffraction (XRD) analysis is a key method which reveals various phases and protective oxides formed on the surfaces of exposed specimens. This paper discusses the XRD study of two boiler steels, namely ASTMSAE213-T22 and SAE-347H with and without High Velocity Oxy-fuel (HVOF) spray Cr₃C₂-NiCr coating, which were exposed to air, molten salt [Na₂SO₄-82%Fe₂(SO₄)₃], and actual boiler environments. XRD analysis has been discussed and the results obtained from the analysis are shown. The performance of the steels was found to improve after the deposition of the coating, which may be attributed to the formation of protective phases.

Abstract: Nanocrystalline indium oxide (In₂O₃) thin film was synthesized by thermal evaporation of indium on unheated Si (110) substrates, followed by wet oxidation process. XRD analyses showed the deposited In2O3 film is of high quality and have cubic structure. The Scherrer structural analysis revealed that the In₂O₃ film grown on Si (110) orientation has nanocrystalline structure with crystallite size of 2.53 nm. Photoluminescence (PL) spectrum showed a strong and broad emission at 574.9 nm with two shoulders at 547 nm and 604 nm which related to oxygen vacancies. Finally, the band gap of nanocrystalline In₂O₃ as determined from the PL spectrum was 2.15± 0.15eV.

Abstract: This paper focus on the effect of different ratio between barium (Ba) and titanium (Ti) to the production of high purity of barium titanate (BT). On this research, the sample was prepared by solid-state reaction between barium carbonate (BaCO₃) and titanium dioxide (TiO₂) powder at constant sintering temperature of 1350 °C. The sample was prepared at different ratio of Ba:Ti which are 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1. All sintered BT was characterized by X-ray diffraction (XRD). All existed phase on these samples was determined and analyzed. Sample from ratio 1:1 produced almost a single phase of BT. While; samples from other ratio produce secondary phase which is barium orthotitanate (Ba₂TiO₄).

Abstract: In this study, about 62.2 wt% Ti₃SiC₂ was synthesized via tungsten inert gas (TIG) welding method, as potential in advanced material applications. This arced sample was characterized using XRD and FESEM analysis to observe the phase presence, and its morphology. Ti₃SiC₂ phase favours to form at 5 s and produces elongated platelets (Ti₃SiC₂) grain, micro-porous equiaxed (TiC) grain and melt regions (Ti-Si), when observed at the dense surfaces. Meanwhile, fine dendrite, quasi-spherical, and pyramidal grains were observed at the pore sites. The laminate dendrite of Ti₃SiC₂ was estimated to form at the origin of TiC faced pyramidal crystal, which nucleated toward TiC pyramidal crystal surface at the specific angle.

Abstract: The effect of recycled copper filled epoxy composites on thermal, electrical and physical properties were investigated. The recycled copper was collected as a waste from the milling machine. The recycled copper filled epoxy composite was mixed using mechanical stirrer. The effect of volume fraction of recycled copper of the epoxy composites were studied based on the coefficient of thermal expansion (CTE), electrical conductivity hardness and density. Incorporation of recycled copper has decreased the CTE of the composites. The electrical conductivity, hardness and density of the composites increased with increasing of volume fraction and filler loading.