Lee Chang Chuan,Ts. Dr.http://dspace.unimap.edu.my:80/xmlui/handle/123456789/435092024-03-29T09:28:21Z2024-03-29T09:28:21ZMorphology and phase evolution in microwave synthesized Al/Fe 3O 4 systemChuan, L.C.,Yoshikawaa, N.,Taniguchia, S.http://dspace.unimap.edu.my:80/xmlui/handle/123456789/436902016-10-19T00:48:58Z2011-01-01T00:00:00ZMorphology and phase evolution in microwave synthesized Al/Fe 3O 4 system
Chuan, L.C.,; Yoshikawaa, N.,; Taniguchia, S.
Thermite reaction between Al/Fe 3O 4raised by microwave (MW) heating under N2 atmosphere has been investigated, and compared with that by the electric furnace. In addition to the stoichiometric ratio for the production of metallic iron and alumina, mixture with slightly lower in Al content is also studied. As thermite reaction is highly exothermic, melting of reaction product and destruction of microstructure may occur, which corresponds to the enthalpy and adiabatic temperature of the reaction. Hence, to avoid this problem, reaction coupled with a smaller driving force by controlling the MW ignition condition at low temperature exotherm has been investigated. The phase and microstructure evolution during the reaction were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Thermogram of the DTA analysis, irrespective of their mole ratio, recorded two exothermic peaks, one at - 1310°C and another one at - 1370°C. When heated by microwave at 955°C, the main products were identified as Al, FeO and Fe, minor amount of Fe 3O 4and some Fe and alumina were detected. When heating to 1155°C, Al and Fe 3O 4peaks disappeared, formation of Fe-Al alloy was observed. For sample heated at 1265°C, a porous body was obtained. Micron sized metal particles with complex morphology, irregular in size and shapes were formed, uniformly distributed within the spinel hercynite and/or alumina matrix. In contrast, conventional heating produced no porous products. Formation of alumina is also observed around the metal particles. Controlling of the reaction progress was possible while heating the sample by MW around the low temperature exotherm region, whereas the combustion wave could not be self-propagated.
2011-01-01T00:00:00ZMicrowave irradiation assisted synthesis of silicon carbide nanotubesTony, V.Voon, C.H.Lee, Chang Chuan, DrLim, B.Y.Rahman, W.Uda, HashimRuslinda, Abdul RahimMohd Khairuddin, Md ArshadFoo, Kai LoongGopinath, S.C.B. ,Ayoib, A. ,Thivina, V. ,Ba Hashwan, S.S.http://dspace.unimap.edu.my:80/xmlui/handle/123456789/436892017-11-29T04:40:49Z2016-01-01T00:00:00ZMicrowave irradiation assisted synthesis of silicon carbide nanotubes
Tony, V.; Voon, C.H.; Lee, Chang Chuan, Dr; Lim, B.Y.; Rahman, W.; Uda, Hashim; Ruslinda, Abdul Rahim; Mohd Khairuddin, Md Arshad; Foo, Kai Loong; Gopinath, S.C.B. ,; Ayoib, A. ,; Thivina, V. ,; Ba Hashwan, S.S.
Conventional methods for the synthesis of silicon carbide were well studied and these methods included carbothermal reduction, mechanical milling, sol-gel process and others. However, conventional methods have limitations such as high energy consumption, presence of impurities and long reaction times. In this paper, microwave heating was applied for the first time for the synthesis of silicon carbide nanotube owing to the advantages of microwave heating such as shorter reaction time, uniform heat distribution and low cost. Mixture of silicon dioxide and carbon nanotube in the ratio of 1:3 as suggested by previous study were mixed in ultrasonic bath using ethanol as liquid medium for 2 hours and then dried on hot plate to evaporate ethanol. The mixture was then cold pressed into 3mm pellet and placed into an alumina crucible filled with silica sand acts as sand insulator and SiC susceptor. The pellet was heated to 1400°C with heating rate of 30°C/min for 40 minute. X-ray diffraction pattern verified the presence of single β-SiC phase in silicon carbide nanotubes. Meanwhile, scanning electron microscopy revealed that tubular structure of carbon nanotube was retained after microwave irradiation and energy dispersive x-ray spectroscopy shown the silicon carbide nanotube consist of only elemental C and Si and thus indicated that silicon carbide nanotubes were successfully synthesized through microwave irradiation.
2016-01-01T00:00:00ZMicrowave-induced substitutional-combustion reaction of Fe 3O4/Al ceramic matrix porous compositeLee, Chang ChuanYoshikawa, NoboruTaniguchi, Shojihttp://dspace.unimap.edu.my:80/xmlui/handle/123456789/435272016-10-17T01:18:25Z2011-11-01T00:00:00ZMicrowave-induced substitutional-combustion reaction of Fe 3O4/Al ceramic matrix porous composite
Lee, Chang Chuan; Yoshikawa, Noboru; Taniguchi, Shoji
Microwave processing and substitutionalcombustion reaction have been utilized to fabricate ceramic matrix porous composite from the thermite reaction of Fe3O4/Al system. Stoichiometric and mixtures with lower and over aluminum were tested. As this system was highly exothermic, the melting of reaction products and destruction the porous structure may occur. In order to avoid that, reaction coupled with a smaller driving force by controlling the microwave (MW) ignition condition at low temperature exotherm, where substitutional reaction occurs has been investigated. The phase and microstructure evolution during the reaction is analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Thermogram of the DTA analysis, irrespective of their mole ratio, recorded two exothermic peaks, one at ∼1310 °C and another one at ∼1370 °C. Fe and α-Al 2O3 were the main products for the combusted mixture. Hercynite appeared as the major phase in the stoichiometric and slightly lower Al content mixtures due to incompleteness of reaction. In contrary, over aluminized mixture revealed the presence of Al3.2Fe. When heated at 1360 °C, an additional FeO phase was observed. Mixtures with extremely low Al content showed the presence of unreacted Fe3O4 and some free Al due to the decrease of combustion velocity associated with a decrease in the sample exothermicities. Sample heated in electric furnace was dense. When heating by microwave, controlling the reaction progress at low temperature exotherm allowed the achievement of porous structure composite consisting of micron size iron particles well distributed and embedded in the hercynite and/or Al2O3 matrix.
2011-11-01T00:00:00ZPorous glass composite as diesel particulate filter and the microwave regenerationLee, Chang ChuanYoshikawa, Noboruhttp://dspace.unimap.edu.my:80/xmlui/handle/123456789/435172016-10-17T01:05:37Z2014-07-01T00:00:00ZPorous glass composite as diesel particulate filter and the microwave regeneration
Lee, Chang Chuan; Yoshikawa, Noboru
In this study, porous SiO2•RO/stainless steel composite body was prepared through the polyurethane sponge replica method. Porous samples obtained through sintering consist of well dispersed and distributed stainless steel particles within the glass matrix. Such microstructure is desired for the purpose as a soot particulate filters (DPF) utilizing microwave rapid and selective heating characteristic, especially during the cold start phase of an engine. Results of microwave heating ability and diesel soot regeneration tests shows that, the fabricated porous composite material is proven to be reliable for rapidly microwave assisted regeneration. Both the regeneration temperature and O2 composition in the supplied gas played an important role in the regeneration process.
2014-07-01T00:00:00Z