Materials Science Forum Vol. 840

Abstract: The characteristics of the starting powder in powder preparation method are important for enhancement of cell performance. In this study, the composite anode powders of NiO–samarium-doped ceria carbonates (SDCC) were prepared by using different NiO loadings (50–70 wt.%) via high-energy ball milling. The composite anode powders were ball-milled in ethanol at a milling speed of 550 rpm. The obtained NiO–SDCC composite anode powders were characterized by XRD, FTIR, FESEM, and EDS. Results indicate that the composite anode powders demonstrated good chemical compatibility between NiO and SDCC, given that no new phases were detected in the XRD analysis. FTIR spectra confirmed that the composite anode powders contain carbonates in amorphous state after high-energy ball milling. FESEM investigation revealed well-distributed fine particles and significant reduction of particle size at nanoscale compared with the powder prepared using NiO particles as the starting material. EDS mapping verified the homogeneity of the composite powder with good elemental distribution. Thus, high-energy ball milling is an effective method to prepare NiO–SDCC composite anode powders within a relatively short processing time.

Abstract: In this study, the alkali treatment of sawdust using different concentration of sodium hydroxide (NaOH) is performed. The purpose of this treatment is to improve the filler-matrix compatibility, thus, enhance the properties of tested specimens under various strain rate condition. The outcome shows the alkali treated sawdust did improve its surface roughness through reduction of sawdust diameter. With this increasing of surface roughness, it will enhance the compatibility between sawdust filler and HDPE matrix. For comparison purpose, the treated and untreated sawdust filler were reinforce in High Density Polyethylene (HDPE) matrix and have been test under static and dynamic loading using Universal Testing Machine (UTM) and Split Hopkinson Pressure Bar (SHPB) apparatus. The results indicate that the stiffness and compression strength properties were improved on treated sawdust composites for both static and dynamic loading compare to untreated sawdust composites.

Abstract: The objective of the study was to evaluate the dimensional stability of experimental particle board panels made from rubberwood (Hevea brasiliensis) using modified starch as binder. Panels were manufactured using 15% corn starch modified with glutardialdehyde and 13% modified starch with 2% Urea Formaldehyde resin as improvement. The particle boards were tested for their dimensional stability towards moisture. Results found that the 2% replacement of modified starch with urea formaldehyde resin showed increment in dimensional stability compared to using glutardialdehyde modified corn starch only as the binder, recorded at 39.38 % and 23.47 % for particleboard with 0.80 g/cm³ density after exposed to 75% and 95 % relative humidity. Therefore, this study indicated that combination of modified corn starch and urea formaldehyde resin can have a potential to be used as an improved binder to produce particle board panels with accepted properties.The objective of the study was to evaluate the dimensional stability of experimental particle board panels made from rubberwood (Hevea brasiliensis) using modified starch as binder. Panels were manufactured using 15% corn starch modified with glutardialdehyde and 13% modified starch with 2% Urea Formaldehyde resin as improvement. The particle boards were tested for their dimensional stability towards moisture. Results found that the 2% replacement of modified starch with urea formaldehyde resin showed increment in dimensional stability compared to using glutardialdehyde modified corn starch only as the binder, recorded at 39.38 % and 23.47 % for particleboard with 0.80 g/cm³ density after exposed to 75% and 95 % relative humidity. Therefore, this study indicated that combination of modified corn starch and urea formaldehyde resin can have a potential to be used as an improved binder to produce particle board panels with accepted properties.

Abstract: Commercially made kaolin is identified as one of the important materials for production of aluminosilicate for catalyst bed support. In this work, an attempt is made to study the potential of local clay for production of aluminosilicate. Three area were identified as kaolin sources in Perak state as they are Trong, Simpang Pulai and Bidor, and labelled as TC, SP and BC, respectively. For preparation of aluminosilicate, formulation using 30% clay and the rest used feldspar (40%) and silica sand (30%). Each batch were formed into ball shapes’ before fired at 1250°C at controlled firing rate of 3°C/min. From the investigation, it is found that only two local clays (CBTC and CBSP) highly potential to be used to produce ceramic ball for catalyst support. In addition, the crushing strength is 100% better than the commercial made product which also have less than 1% water absorption.

Abstract: Research on tellurite based glass has become important because of it potential in photonic and shielding material. In this work, the changes of the optical properties of ternary tellurite glasses when radiated with 25kGy gamma ray dose were studied. Five glass samples, with composition [(TeO₂)₇₀ (B₂O₃)₃₀]_100-x (Bi₂O₃)_x (where x = 5, 10, 15, 20 and 25 mol%) were prepared by melt quenching technique. The optical properties were studied by UV-Visible absorption. The X-Ray Diffraction (XRD) spectra result shows that all glass samples fit the amorphous state. The Fourier Transform Infrared Spectroscopy (FTIR) was used to explore the structural bonding in the prepared glass samples due to exposure. Gamma irradiation causes a profound change in the peak intensity as shown by FTIR spectra which is due to the breaking of the network bonding. Before gamma irradiation, the optical band gap, E_g value decreased from 2.50 eV to 2.30 eV with the addition of Bismuth content. The value kept decreasing (from 2.18 eV to 2.05 eV) following exposure to 25 kGy gamma irradiation due to the increase of non-bridging oxygen (NBO) and the increase of defect in the glass. The finding suggest that the glass with high content of Bi₂O₃ (25 Bi) give smallest E_g and show less changes (less defect) in FTIR spectra after gamma irradiation which indicate that this glass is more resistant to 25 kGy gamma irradiation dose compared to other glasses.

Abstract: Silantek clay deposits were characterized and evaluated for their potential as structutral ceramic products raw materials through chemical, mineralogical and refractory (1250 to 1600^o C) properties determinations. Results show that the main oxides in the samples were SiO₂ and Al₂O₃, whereas the other oxides present only in small quantity. Kaolinite(Al₂Si₂O₅(OH)₄) and quartz(SiO₂) present as dominant mineral phases and the minor phases of mullite(Al₆Si₂O₁₃) and zeolite(Na₂Al₂Si₃O₁₀·2H₂O) also appeared in the samples. From the results of the refractoriness tests up to 1600°C, samples ST11, ST23A, ST31A, ST31B, ST33 have potential for refractory products as they demonstrated high thermal resistance properties(over 1600°C). Silantek clay potential to be used as raw materials mainly for refractory, structural ceramics and other common ceramic products

Abstract: CaCu_2.8Co_0.2Ti₄O₁₂ ceramics were prepared by microwave-assisted sol gel method. The properties of materials can be highly dependent on crystallite size therefore measuring the crystallite size is among the important part in materials research work. In the present study, the crystallite size of the CaCu_2.8Co_0.2Ti₄O₁₂ ceramics sintered at temperature ranged from 975-1125°C were investigated. Different methods, approach and strategy of crystallite size measurement were demonstrated in this papers.Keywords: Crystallite size, CCTO

Abstract: Bioinert titanium (Ti) can be modified to bioactive by performing various techniques including anodic oxidation. Where, this method encompasses electrode reactions in combination with electric field driven metal and oxygen ion diffusion to the formation of an oxide film on anode surface. The objective of this study is to evaluate the effect of current density of anodic oxidation upon the characteristic of titanium in sulphuric acid (H₂SO₄) under various conditions. The modified titanium was prepared using anodic oxidation method in 0.3 M of sulphuric acid as electrolyte. The applied voltage and current density of the anodic oxidation parameters were varied from 50 – 200 V and 25 – 75 mA.cm^-2 respectively for 10 min of oxidation process at room temperature. The effects of anodic oxidation on the titanium were characterised using X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The results show that by increasing the current density of the anodic oxidation, different mineralogy, surface morphology, and surface profile were produced. At low current density (25 mA.cm^-2), high voltage is needed to produce high crystalline of anatase formed on the titanium surface and only able to produced very low of rutile titanium with 200 V of applied voltage compared to high current density (75 mA.cm^-2) with same applied voltage, very high rutile crystal with mixture of low anatase was observed on the titanium. This modified oxide of titanium has potentially to be applied in biomedical as implant.

Abstract: Black tilapia (Oreochromis mossambicus) fish skins are good alternatives sources of gelatin. Vast variations in extraction procedures affect the properties of fish gelatin such as yield and gel strength. Thus, this study explores the effect of pretreatment durations on the properties of black tilapia skin gelatin. Gelling properties such as gel strength (bloom value) of the gelatin samples had been determined. Highest gel strength had been detected for gelatin treated at 24 h (390.1 g), followed by 16 h (287.1 g) and 8 h (141.2 g). In contrast, gelatin treated at 24 h indicates lower yield on wet weight basis (14.12 %) than those treated at 16 h (14.96 %) and 8 h (16.90 %). The possible interactions and characteristics between the functional groups in the gelatin samples have also been perceived via Fourier Transform Infrared Spectroscopy (FTIR) analysis.

Abstract: Hydroxyapatite extensively used for orthopaedic and dental reconstruction as biomaterials due to their chemical and biological similarity to human hard tissue. Therefore, this paper describes the extraction of natural hydroxyapatite from tilapia fish scale via a conventional heat treatment. The calcination temperatures (600, 800, 1000, and 1200°C) were varied. XRD results indicated that the presences of biphasic phase (HA/β-TCP) were identified during heat treatment. Transformation of biphasic phase to single phase (β-TCP) can be observed at 1200°C, results on decomposition of hydroxyapatite. The degree of crystallinity and crystallite size originated increase with the calcination temperature. The FT-IR spectra confirmed that all organic compounds were eliminated during the heat treatment process. FESEM images were used to determine the size and shape of grains of calcined samples. The biphasic mineral grain size was estimated in range of 500 – 100 nm. The analysis show that variation of calcination temperatures significantly impact on the properties of hydroxyapatite derived from tilapia fish scale.