Papers by Keyword: Aluminium Oxide

Abstract: Aluminium based Metal Matrix Composites (MMCs) with Aluminium matrix and non-metallic reinforcements are finding extensive applications in automotive, aerospace and defence fields because of their high strength-to-weight ratio, high stiffness, hardness, wear-resistance, high-temperature resistance, etc. Composite materials are frequently chosen for structural applications because they have desirable combinations of mechanical characteristics. Development of hybrid metal matrix composites has become an important area of research interest in Material Science. In this work, the Aluminium alloy is reinforced with 3,5,7,9 wt. % of Al₂O₃ and 2 wt. % of SiC to prepare the hybrid composite. The present study is aimed at evaluating the physical properties of aluminium 7075 in the presence of silicon carbide, aluminium oxide and its combinations. The compositions are added up to the ultimate level and stir casting method is used for the fabrication of aluminium metal matrix composites. The mechanical behaviours of metal matrix composites like tensile strength, and hardness test are investigated by conducting laboratory experiments. Mechanical properties like micro hardness and tensile strength of Al7075 alloy increase with the addition of SiC and Al₂O₃ reinforcements.

Abstract: Researchers in applied thermal engineering found that nanofluid have potential as a heat transfer fluid with high level of enhancement in heat transfer process compared to conventional coolants. This study present investigation on viscosity for nanoparticles Aluminium Oxide (Al₂O₃) dispersed in ethylene glycol prepared using two step method. Viscosity measurement is conducted using Brookfield LVDV-III Viscometer at temperature ranging from 30 °C to 80 °C. Nanofluid is prepared using Al₂O₃ in 13 nm size at volume concentration ranging from 0.5 % to 2.0 %. The result indicates that viscosity for Al₂O₃ nanofluid is 75.2 % higher than based fluid at 1.5 % volume concentration and temperature of 30 °C. It was observed that viscosity is inversely proportional with the increment of nanofluid volume concentration and temperature.

Abstract: Nanofluids are the new coolant fluid that has been widely investigates due to its ability to improved heat transfer better than conventional heat transfer fluid. The need to study the nanofluid properties has been increased to provide better understanding on nanofluid thermal properties and behavior. This study presents the measurement analysis on thermal conductivity enhancement of Al₂O₃ nanoparticles dispersed in ethylene glycol. The nanofluids are prepared using two step method for volume concentration range from 1.0 % to 4.0 %. The thermal conductivity measurement of the nanofluid is performed by KD2 Pro Thermal Properties Analyzer at working temperature range from 30 °C to 80 °C. The maximum enhancement in thermal conductivity is 21.1 % at volume concentration of 2.0 % and temperature of 70 °C. The results show that the thermal conductivity increases with the increase of nanofluid concentration and temperature. Also, the nanofluid shows enhancement in thermal conductivity compare to the base fluid.

Abstract: This paper evaluate how colorimetry change of ethylene propylene diene rubber (EPDM)/Aluminium oxide (Al₂O₃) composites when added with four types of crystallized resins. The results indicate that the filler Al₂O₃ can turn EPDM control from lighter, redder, and yellower to darker, greener and bluer, respectively. The total color change (ΔE) of EPDM/Al₂O₃ composites increase with the decrease amount of crystal lattices. EPDM/Al₂O₃/Polypropylene (PP) composite, with the highest crystallinity of PP, has little change of the lightness value and the total color change of EPDM compostes due to light scatter.

Abstract: Ceramic materials have been widely utilized due to its attractive properties including high resistance to extremely harsh environments; chemical and heat, and its durability to the remarkable mechanical strength. Inorganic flat sheet films in this study were prepared by dry-wet phase inversion process followed by sintering method, which expected to produce very unique micro-structures leading to improvement in performance for various applications including catalytic reactions and filtration processes. Aluminium oxide was chosen as the main material due its known capability in filtration processes, membrane reactors and membrane catalysis applications. Polyethersulfone (PES) was used as an organic binder in the membrane dope formulation. Besides alumina and PES, the dope solution was consisted of N-methyl-2-pyrrolidone (NMP) and arlacel as solvent and additive, respectively. The main aim of this study is to investigate the effect of sintering temperature on the morphology and structure of the prepared membranes. Scanning electron microscope (SEM) was used to examine the membrane structure. Since the morphology of a membrane highly influences its mechanical properties, the membrane strength was measured using tensile test. From the SEM, preliminary cast membrane structure displayed a long finger-like near the outer and inner walls sandwiched a sponge-like structure that provided the membrane strength.

Abstract: Metal to the metal wear analysis of Aluminium (Al6061grade) alloy, dis-continuously reinforced with ceramic particles of SiC and Al₂O₃ deliver this paper. The Al matrix with 5 to 25% of vol. Fractions of SiC and Al₂O₃ particulate reinforcements were formed in Hybrid Metal Matrix Composite (HMMC) by stirring casting technology. They are finding applications in automotive, aeronautical and sport goods. For the proper use of these composites, its mechanical properties and wear properties are to be evaluated. The dry sliding behavior of these SiC and Al₂O₃ particulates HMMCs and that of Al alloy at atmosphere was analyzed with a pin on disc type wear testing machine. The result indicates that, the scanning electron micrographs of the worn surfaces of the hybrid composites show the worn surface of the composite alloy is rougher than the unreinforced Al6061alloy.

Abstract: Carbon decomposition of liquor afger desilication from nephine was investigated, aluminium oxide was prepard by anneal of Al (OH)₃ separated out from carbon decompositon, and analysis of radionuclide of both above process was performed. The results show decomposition rate of sodium aluminate can be obtained when experiments of carbon decomposition of liquor after desilication using CO₂ of hight concentration, and it is beneifit for the crystal growth of Al (OH)₃, filtration and separation. Great mass of nuclide exists in the mother solution of carbon decomposition, and few into Al (OH)₃, which could be regarded as wiout radioactive contamination. .

Abstract: To solve the technical problem of LED chips with top and back electrodes can only forms parallel connection; this paper provided integrated packaging structure by using silver reflective layers, aluminium oxide and aluminum plate. LED chips with top and back electrodes, according to a certain permutations and combinations way, were packaged integrally on the independent silver reflective layers. The silver reflective layers were on the aluminum plate with aluminium oxide insulating layer. Studies show that when the LED chips with top and back electrodes packaged on aluminum plate with aluminium oxide insulating layer are easier to achieve parallel and series connection. Moreover, the LED integrated package devices has higher driving voltage and lower driving current than traditional LED integrated package devices with top and back electrodes. In addition, independent silver reflective layers can provide integrated package devices with a better luminous efficiency.

Abstract: Aluminium oxide is one of the metal oxides that can exist in many phases such as α, θ, η etc. All the phases obtained are affected by annealing temperature and synthesis route. In this research the Al₂O₃ powders were synthesized by the combustion method using triethanolamine as fuels. A pure η phase as well as a mixed α and η phases were obtained. The size and morphology of Al₂O₃ particles were studied using scanning electron microscopy (SEM).

Abstract: Aim To explore pigmented glass for infiltration and investigate its physical and mechanical properties. Methods The pigmented glass was prepared by melting glass components in an alumina crucible at 1400°C for 2h. The thermal properties were tested using a Setaram-TGDTA 92 analyzer; three point bending strength and fracture toughness were also tested; the microstructure of the glass was studied using a scanning electron microscope. Results The thermal expansion coefficient over the range 20–600 °C was 6.2 × 10-6 °C -1, Tg was about 690 °C, the density, bending strength, fracture toughness and Vickers hardness were 2.23 g/cm3, 118 MPa, 1.22 MPam1/2, and 7.4 GPa respectively. Conclusion The pigments have no detrimental effects on the physical and mechanical properties; thus the pigmented glass for infiltration has favorable physical and mechanical properties and also good compatibility with presintered porous alumina.