Advanced Materials Research Vol. 1087

Abstract: Cobalt Chromium Molybdenum (CoCrMo) generally known as a highly resistant to corrosion and wear performance. CoCrMo was prepared using replication method. The aim of this paper is to producing CoCrMo foam that will be given to consider the properties of CoCrMo foam after sintering process. The CoCrMo slurry was produced by mixing CoCrMo powder with Polyethylene Glycol (PEG), Carboxyl Methyl Cellulose (CMC) and distilled water. The polymeric foam template was impregnated in CoCrMo slurry and dried at room temperature. Sintering was carried out in a high temperature tube furnace at 1300°C. After the sintering process, the microstructure of the CoCrMo foam produced was observed by Scanning Electron Microstructure (SEM) and the elemental analysis was carried by Energy Dispersive X-ray Spectroscopy (EDS). While, X-Ray Diffraction (XRD) is used to characterize the chemical composition and structure of the samples. The EDS analysis performed in all samples with composition of 65 wt % CoCrMo foam show the presence of of Cr, Mo, Co, Mn, C, O, Al, Si and Ca. From the XRD results, the pattern that was detected all the peak was PDF 2007: 00-041-0943(Cobalt Nitride).

Abstract: Copper (II) palmitate complex was synthesized using an electrochemical technique in the presence of palm-based palmitic acid as the ligand and Cu (II) ions from the slow released of anode material through the electrochemical oxidation of Cu foil. The system consisted of Cu foil and a graphite rod as the anode and cathode, respectively, while ammonium acetate was used as a supporting electrolyte. X-ray diffraction and spectroscopic studies were carried out to characterize the synthesized complexes using powder XRD, XPS, FTIR and UV-Vis. The results obtained showed that the desired Cu (II)Pa complex was successfully synthesized using the electrochemical technique. The surface morphology of the complexes was analyzed using FESEM, and the micrograph obtained showed that the synthesized complexes formed nanosized matchstick-like structures. This conclusion is supported by the TEM micrograph which shows the presence of nanoparticles with different diameter ranges from 2 to 3 nm.

Abstract: The performance of zirconia toughened alumina with addition of MgO additives is investigated. Optimized composition of MgO at 1.1 wt% was used in the composition with alumina/yittria stabilized zirconia (YSZ). The composition was mixed, uniaxially pressed into rhombic 80o cutting inserts with 0.8 mm nose radius and sintered at 1600oC for 4 h in pressureless condition. For machining analysis, commercial stainless steel 316L with 12 mm diameter were used as workpiece. The workpiece was machined at 625 to 1750 rpm. Tool wear and surface roughness of workpiece were measured. Result shows three types of wear behaviour appear which are flank wear, notch wear and chipping. Flank wear and notch wear increased with the cutting speed but decrease by increasing the feedrate before increased after passing the 0.2mm/rev feedrate. While chipping very much related to the feedrate as the chipping area increased when the feedrate increased. Meanwhile, surface roughness increase with increment of cutting speed and feedrate which match the wear pattern.

Abstract: In recent decades, dependence on fossil fuels resources has shifted into derivation of cellulose based materials to replace the non-renewable resources. Lignocellulosic biomass is the most abundant feedstock on earth and is one of the promising renewable and sustainable resources. In the present study, simple preparation of nanocellulose particles by using ionic liquid (1-butyl-3-methylimidazolium hydrogen sulfate) has been introduced by investigating the influence of reaction temperature (room temperature and heat treated at 90°C). The resultant samples were characterized using X-Ray Diffraction (XRD) and Fourier-Transform Infrared Spectroscopy (FTIR). Interestingly, it was found that the high crystallinity sample could be synthesized at temperature of 90°C. The reason might be attributed to ionic liquid enter into the space between cellulose chains and caused cellulose molecules progressively swelled up when heated. Consequently, amorphous regions of cellulose were dissolved by ionic liquid and crystalline parts of cellulose were leave in the cellulose structure. From the XRD data, it could be observed that sharper crystalline peak and higher crystallinity index (CrI) present within heat-treated samples which corresponded to higher crystalline structure of cellulose I. While the broader peak and lower CrI of untreated cellulose samples indicated lower crystalline structure of cellulose I. Pretreatment of cellulose with ionic liquid can provides a facile approach for the preparation of nanocellulose particles with high crystallinity.

Abstract: At room temperature, dehydrating agent, concentrated sulfuric acid (H₂SO₄) was used to form porous carbon (BAC) from bamboo waste shows good properties as CO₂ adsorbent. Selection of nano-CuO supported BAC produce composite materials with high total surface area and smaller pores size composite of 660.8 cm²/g and 2.7 nm. XRD data showed the support data to confirm the hydroxide phase formation as intermediate for carbonate and accelerate the CO₂ chemisorption reaction. Besides, the presence of BAC together with metal oxide can improve the CO₂ interaction physically on the surface and pores resulting the higher adsorption capability of 32.2 cm³ of CO₂ per gram adsorbent. The combination of nano-CuO on BAC become a good adsorbent which can stimulate the CO₂ reduction programme as well as reduce the CO₂ emissions during BAC production.

Abstract: Anodic oxidation is a surface modification method which combines electric field driven metal and oxygen ion diffusion for formation of oxide layer on the anode surface. Anodised titanium has been widely use in biomedical applications especially in dental implant. This study aimed to investigate the effect of electrolyte concentration on titanium. Specifically, the titanium foil was anodised in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA) with different concentration (0.02 M + 0.2 M and 0.04 M + 0.4 M), anodising time (10 min), applied voltage (150, 200, 250, 300 and 350 V) and current density (10 mA.cm^-2) at room temperature. Surface oxide properties of anodised titanium were characterised by using glancing angle X-ray diffraction (GAXRD), field emission scanning electron microscope (FESEM), focused ion beam (FIB) milling and digital camera. With increasing electrolyte concentration, the oxide layer became more porous. The GAXRD results also showed that rutile formed at high applied voltage (≥300 V) when the higher concentration of electrolyte was used.

Abstract: Palm oil fuel ash (POFA) is a by-product from agricultural waste produced thousand tonnes every year. This paper presents the use of treated POFA as a substitute material for quartz in fabricating an improved porcelain ceramic. Untreated POFA was dried in an oven at 100 oC for 24 h. Then, it was ground in a ball mill for 1.5 h with the revolution rate of 200 rev/min to reduce the particle size. Next, it was sieved to remove the particles coarser than 50 μm. The POFA was treated by heating it at a temperature of 600 oC for 1.5 h. The mixed powder was then pressed into pellets at mould pressure of 31 MPa, 61 MPa, 91 MPa and 121 MPa. All the pellets were sintered at the temperature of 1100 oC for 2 h soaking time. It was found that the highest compressive strength of 34 MPa is at 15 wt% POFA and mould pressure of 91 MPa. The increment in the strength could be attributed from the changes in the microstructural features as a result of an optimum applied pressure.

Abstract: Effect of ultrasonic treatment on the oxidation kinetics and microstructure of Fe₈₀Cr₂₀ alloy is investigated. The aim of this study is to improve the surface morphology and oxidation resistance of the Fe₈₀Cr₂₀ alloy powder as a raw material. Ultrasonic technique is very promise technology and not yet fully explored. The Fe₈₀Cr₂₀ material was treated by ultrasonic technique (UT) at various times of 3.5 h, 4.5 h, 5 h and followed by cold compaction with force of 13 Newton. The oxidation test was carried out using tube furnace under argon gas environment with 5 cycles, which has been considered. It was found that the UT has improved the surface morphology of the material effectively. Ultrasonic was revealed that the good interparticle bonding when experimented with ultrasonic treatment at 4.5 h. In the oxidation test, the lowest mass gain of 68 mg/cm² was found at the oxidation time of 100 h. Meanwhile, the lowest parabolic rate constant of 6.8198 x 10^-14 g²cm^-4s^-1 was revealed when ultrasonic for 4.5 h sample.

Abstract: The sulfur crosslinking films from Natural Rubber (NR), Carboxylated Stryrene Butadiene Rubber (XSBR) latices, and their blends have been investigated using X-ray absorption near-edge structure spectroscopy (XANES). The film was prepared by casting the latex compound on glass surface and heating at 120^oC in a hot air oven for 10 minutes. The sulfur crosslinking density were studied by the XANES. This was done to provide the local geometry and electronic environment of sulfur bonding in the rubber networks. We found that the reversion takes place before the onset of oxidative processes at the sulfur bridges. Parallel to the oxidative processes, the production of cyclic sulfanes takes places. This relationship depends on the rubber compositions.

Abstract: Silica dioxide (SiO₂) can be modified by impregnating amine-containing compound to improve CO₂ adsorption capacity. Octadecylamine (ODA) was supported on silica dioxide particles. The amine-modified samples were characterized using FTIR, BET and XRD. Carbamate ion pair formation on surface of adsorbents was analyzed by XPS. Reactivity of solid sorbents towards CO₂ was evaluated using isothermal CO₂ adsorption by BET. This study shows 25 wt % ODA/SiO₂ can adsorb 2.45 wt % CO₂/adsorbent is slightly higher in adsorbing CO₂ compared to pure SiO₂ which only adsorb 1.85 wt % CO₂/adsorbent.