Zircon has excellent thermal, chemical, and mechanical properties, but it is hard to make a dense sintered product because of dissociation during the sintering process. This study analyzes how the addition of SiO2 and Al2O3 affects the mechanical properties of sintered zircon, particularly in regards to reducing the thermal dissociation and improving the mechanical properties of ZrSiO4. Zircon specimens containing different amounts of SiO2 and Al2O3 were prepared and sintered to observe how the mechanical properties of ZrSiO4 changed according to the differing amount of SiO2 and Al2O3. The ZrSiO4 that was used for the starting material was ground by ball mill to an average particle size of 3 μm. The SiO2 and Al2O3 that was used for additives were ground to an average particle size of 3 μm and 0.5 μm, respectively. Adding SiO2 resulted in transformation in the liquid phase at high temperatures, which had little effect on suppressing the thermal dissociation but enhanced the mechanical properties of ZrSiO4. When Al2O3 was added, the mechanical properties of ZrSiO4 decreased due to the formation of pores and abnormal grains in the microstructure of the sintered zircon.

The influence of sulfate on the selective catalytic reduction of on the Ag/ catalyst was studied when was used as a reducing agent. Various preparation methods influenced differently on the activity. Among the methods, cogelation precipitation gave best activity. When sulfates were formed on the surfaces of samples prepared by impregnated and deposition precipitation, activity was enhanced as long as suitable forming condition is satisfied. The major sulfate formed in Ag/ catalyst was the aluminum sulfate and it seems that this sulfate acted as a promoter. When Mg was added to the Ag/ catalyst it promoted activity at high temperature. Intentionally added sulfate also enhanced activity, when their amount was confined less than 3 wt%.

La doped CuO-ZnO-Al2O3 powders are prepared by sol-gel method with aluminum isopropoxide and primarydistilled water as precursor and solvent. In this synthesized process, the obtained metal oxides caused the precursor such ascopper (II) nitrate hydrate and zinc (II) nitrate hexahydrate were added. To improve the surface areas of La doped CuO-ZnO-Al2O3 powder, sorbitan (z)-mono-9-octadecenoate (Span 80) was added. The synthesized powder was calcined at varioustemperatures. The dopant was found to affect the surface area and particle size of the mixed oxide, in conjunction with thecalcined temperature. The structural analysis and textual properties of the synthesized powder were measured with an X-rayDiffractometer (XRD), a Field-Emission Scanning Electron Microscope (FE-SEM), Bruner-Emmett-Teller surface analysis (BET),Thermogravimetry-Differential Thermal analysis (TG/DTA), 27Al solid state Nuclear Magnetic Resonance (NMR) and transforminfrared microspectroscopy (FT-IR). An increase of surface area with Span 80 was observed on La doped CuO-ZnO-Al2O3powders from 25m2/g to 41m2/g.

The transesterification of rapeseed oil, soybean oil, and mixed fat were conducted at 65℃ with Al2O3-supported CaO, 0.8 wt% KOH, 1 wt% NaOH and mixed catalyst. The overall conversion(%) of rapeseed oil indicated to be 96% at the 12:1 molar ratio of methanol to oil, 8 wt% CaO and 2 wt% water. The pH ranges of biodiesel for mixed fat using four catalysts and for three fats using 8wt% CaO were 7.3-9.1, 7.3-7.5, respectively. The volumes of water needed to wash biodiesel from rapeseed oil using 0.8 wt% KOH and 8 wt% CaO were 15 mL and 3 mL.

A promising candidate material for a H2 permeable membrane is SiC due to its many unique properties. Ahydrogen-selective SiC membrane was successfully fabricated on the outer surface of an intermediate multilayer γ-Al2O3 witha graded structure. The γ-Al2O3 multilayer was formed on top of a macroporous α-Al2O3 support by consecutively dipping intoa set of successive solutions containing boehmite sols of different particle sizes and then calcining. The boehmite sols wereprepared from an aluminum isopropoxide precursor and heated to 80oC with high speed stirring for 24 hrs to hydrolyze theprecursor. Then the solutions were refluxed at 92oC for 20 hrs to form a boehmite precipitate. The particle size of the boehmitesols was controlled according to various experimental parameters, such as acid types and acid concentrations. The topmost SiClayer was formed on top of the intermediate γ-Al2O3 by pyrolysis of a SiC precursor, polycarbosilane, in an Ar atmosphere. Theresulting amorphous SiC-on-Al2O3 composite membrane pyrolyzed at 900oC possessed a high H2 permeability of 3.61×10−7mol·m−2·s−1·Pa−1 and the H2/CO2 selectivity was much higher than the theoretical value of 4.69 in all permeation temperatureranges. Gas permeabilities through a SiC membrane are affected by Knudsen diffusion and a surface diffusion mechanism,which are based on the molecular weight of gas species and movement of adsorbed gas molecules on the surface of the pores.

Al2O3 has received wide attention with established use as a catalyst and growing application in structural or functional ceramic materials. On the other hand, the boehmite (AlO(OH)) obtained by sol-gel process has exhibited a decrease in surface area during phase transformation due to a decline in surface active site at high temperature. In this work, Al2O3-CuO/ZnO (ACZ) and Al2O3-CuO/CeO (ACC) composite materials were synthesized with aluminum isopropoxide, copper (II) nitrate hemi (pentahydrate), and cerium (III) nitrate hexahydrate or zinc (II) nitrate hexahydrate. Moreover, the Span 80 as the template block copolymer was added to the ACZ/ACC composition to make nano size particles and to keep increasing the surface area. The ACZ/ACC synthesized powders were characterized by Thermogravimetry-Differential Thermal analysis (TG/DTA), X-ray Diffractometer (XRD), Field-Emmision Scanning Electron Microscope (FE-SEM), Bruner-Emmett-Teller (BET) surface analysis and thermal electrical conductivity (ZEM-2:M8/L). An enhancement of surface area with the addition to Span 80 surfactant was observed in the ACZ powders from 105 m2/g to 142 m2/g, and the ACC powders from 103 m2/g to 140 m2/g, respectively.

Electrical discharge machining (EDM) is an attractive machining technique but it requires electrically conductive ceramic materials. In this study, Alumina matrix composites reinforced with CNTs were fabricated through CNT purification, mixing, compaction and spark plasma sintering (SPS) processes. nanocomposites with the different CNT concentrations were synthesized. The mechanical and electrical characteristics of /CNTs composites were examined in order to apply the materials to the EDM process. In addition, micro-EDM using wire electrical discharge grinding (WEDG) was conducted under the various EDM parameters to investigate the machining characteristics of machined hole by Field Emission Scanning Electron Microscope (FE-SEM). The results show that /CNTs 10%Vol. was more suitable than the other materials because high conductivity and large discharge energy caused violent sparks resulting in bad machining accuracy and surface quality.

In fabricating plasma display panels, the photolithographic process is used to form patterns of barrier ribs with high accuracy and high aspect ratio. It is important in the photolithographic process to control the refractive index of the photosensitive paste. The composition of this paste for photolithography is based on the B2O3-SiO2-Al2O3 glass system, including additives of alkali oxides and rare earth oxides. In this work, we investigated the density, structure and refractive index of glasses based on the B2O3-SiO2-Al2O3 system with the addition of Li2O, K2O, Na2O, CaO, SrO, and MgO. The refractive index of the glasses containing K2O, Na2O and CaO was similar to that of the [BO3] fraction while that of the SrO, MgO and Li2O containing glasses were not correlated with the coordination fraction. The coordination number of the boron atoms was measured by MAS NMR. The refractive index increased with a decrease of molar volume due to the increase in the number of non-bridging oxygen atoms and the polarizability. The lowest refractive index (1.485) in this study was that of the B2O3-SiO2-Al2O3-K2O glass system due to the larger ionic radius of K+. Based on our results, it has been determined that the refractive index of the B2O3-SiO2-Al2O3 system should be controlled by the addition of alkali oxides and alkali earth oxides for proper formation of the photosensitive paste.

A new High Frequency Induction Heating (HFIH) process has been developed to fabricate dense reinforced with Fe-Ni magnetic metal dispersion particles. The process is based on the reduction of metal oxide particles immediately prior to sintering. The synthesized /Fe-Ni nanocomposite powders were formed directly from the selective reduction of metal oxide powders, such as NiO and . Dense /Fe-Ni nanocomposite was fabricated using the HFIH method with an extremely high heating rate of . Phase identification and microstructure of nanocomposite powders and sintered specimens were determined by X-ray diffraction and SEM and TEM, respectively. Vickers hardness experiment were performed to investigate the mechanical properties of the /Fe-Ni nanocomposite.

The Charge Trap Flash (CTF) memory device is a replacement candidate for the NAND Flash device. In this study,Pt/Al2O3/La2O3/SiO2/Si multilayer structures with lanthanum oxide charge trap layers were fabricated for nonvolatile memorydevice applications. Aluminum oxide films were used as blocking oxides for low power consumption in program/erase operationsand reduced charge transports through blocking oxide layers. The thicknesses of SiO2 were from 30Å to 50Å. From the C-Vmeasurement, the largest memory window of 1.3V was obtained in the 40Å tunnel oxide specimen, and the 50Å tunnel oxidespecimen showed the smallest memory window. In the cycling test for reliability, the 30Å tunnel oxide sample showed an abruptmemory window reduction due to a high electric field of 9~10MV/cm through the tunnel oxide while the other samples showedless than a 10% loss of memory window for 104cycles of program/erase operation. The I-V measurement data of the capacitorstructures indicated leakage current values in the order of 10-4A/cm2 at 1V. These values are small enough to be used in non-volatile memory devices, and the sample with tunnel oxide formed at 850oC showed superior memory characteristics comparedto the sample with 750oC tunnel oxide due to higher concentration of trap sites at the interface region originating from the roughinterface.

The pressureless sintering behavior of /Cu powder mixtures, prepared from /CuO and /Cu-nitrate, has been investigated. Microstructural observation revealed that powders with nano-sized Cu particles could be synthesized by hydrogen reduction method. The specimens, pressureless-sintered at for 4 min using infrared heating furnace with the heating rate of /min, showed the relative density of above 90%. Maximum hardness of 16.1 GPa was obtained in /MgO/Cu nanocomposites. The nanocomposites exhibited the enhanced fracture toughness of 4.3-5.7 , compared with monolithic . The mechanical properties were discussed in terms of microstructural characteristics

Nanopowders of and FeAl were fabricated by high energy ball milling. Dense 4.25 composite was simultaneously synthesized and consolidated by high frequency induction heated combustion method within 2 min from mechanically activated powders. Consolidation was accomplished under the combined effects of a induced current and mechanical pressure of 80 MPa.

Effect The effect of sintering additives (SiO2, Al2O3, Clay) on the mechanical characteristics of sintered zircon was investigated. 1 vol% of additives in zircon powder was was sintered at 120~1500˚C, the mechanical characteristics were measured, and microstructure analysis were was conducted. Al2O3 and clay additions increase the formation of monoclinic and tetragonal-ZrO2 formation. An addition of SiO2 addition suppressed the formation of tetragonal-ZrO2 formation., The A specimen sintered at 1400˚C showed the a density of 4.05 g/cm3 and the a microhardness of 1120 HV, respectively.

High-energy mechanical milling (HEMM) and sintering into Al-Mg alloy melt were employed tofabricate an Al alloy matrix composite reinforced with submicron and micron sized Al2O3 particles. Al-basedmetal matrix composite (MMC) reinforced with submicron and micron sized Al2O3 particles was successfullyfabricated by sintering at 1000oC for 2h into Al-Mg alloy melt, which used high energy mechanical milled Al-SiO2-CuO-ZnO composite powders. Submicron/micron-sized Al2O3 particles and eutectic Si were formed by in situdisplacement reaction between Al, SiO2, CuO, and ZnO during sintering for 2h into Al-Mg alloy melt and werehomogeneously distributed in the Al-Si-(Zn, Cu) matrix. The refined grains and homogeneously distributedsubmicron/micron-sized Al2O3 particles had good interfacial adhesive, which gives good wear resistance withhigher hardness.

A new cost-effective atomic layer deposition (ALD) technique, known as Proximity-Scan ALD (PS-ALD) was developed and its benefits were demonstrated by depositing Al2O3 and HfO2 thin films using TMA and TEMAHf, respectively, as precursors. The system is consisted of two separate injectors for precursors and reactants that are placed near a heated substrate at a proximity of less than 1 cm. The bell-shaped injector chamber separated but close to the substrate forms a local chamber, maintaining higher pressure compared to the rest of chamber. Therefore, a system configuration with a rotating substrate gives the typical sequential deposition process of ALD under a continuous source flow without the need for gas switching. As the pressure required for the deposition is achieved in a small local volume, the need for an expensive metal organic (MO) source is reduced by a factor of approximately 100 concerning the volume ratio of local to total chambers. Under an optimized deposition condition, the deposition rates of Al2O3 and HfO2 were 1.3 Å/cycle and 0.75 Å/cycle, respectively, with dielectric constants of 9.4 and 23. A relatively short cycle time (5~10 sec) due to the lack of the time-consuming "purging and pumping" process and the capability of multi-wafer processing of the proposed technology offer a very high through-put in addition to a lower cost.

This article presents the challenges toward the successful consolidation of nanopowder using magnetic pulsed compaction (MPC). In this research the ultrafine-structured bulks have been fabricated by the combined application of magnetic pulsed compaction (MPC) and subsequent sintering, and their properties were investigated. The obtained density of bulk prepared by the combined processes was increased with increasing MPC pressure from 0.5 to 1.25 GPa. Relatively higher hardness and fracture toughness in the MPCed specimen at 1.25 GPa were attributed to the retention of the nanostructure in the consolidated bulk without cracks. The higher fracture toughness could be attributed to the crack deflection by homogeneous distribution and the retention of nanostructure, regardless of the presence of porosities. In addition, the as consolidated bulk using magnetic pulsed compaction showed enhanced breakdown voltage.

The wetting behavior of molten Fe on α-Al2O3 single crystals with three different crystallographic orientations, R(01ar12), A(11ar20), and C(0001), was investigated using the sessile drop method under a 10%H2-Ar atmosphere at 1873 K. It was found that the differences in the contact angle of the three differently oriented α-Al2O3 single crystals were not significant (within 5˚, which corresponded to the changes in the work of adhesion of 157mJ/m2) due to the surface reconstruction.

The bi-materials with Al-Mg alloy and its composites reinforced with SiC and particles were prepared by conventional powder metallurgy method. The A1-5 wt%Mg and composite mixtures were compacted under , and then the mixtures compacted under 400 MPa were sintered at for 5h. The obtained bi-materials with Al-Mg/SiCp composite showed the higher relative density than those with composite after compaction and sintering. Based on the results, the bi-materials compacted under 400 MPa and sintered at 873K for 5h were used for mechanical tests. In the composite side of bi-materials, the SiC particles were densely distributed compared to the particles. The bi-materials with Al-Mg/SiC composite showed the higher micro-hardness than those with composite. The mechanical properties were evaluated by the compressive test. The bi-materials revealed almost the same value of 0.2% proof stress with Al-Mg alloy. Their compressive strength was lower than that of Al-Mg alloy. Moreover, impact absorbed energy of bi-materials was smaller than that of composite. However, the bi-materials with Al-Mg/SiCp composite particularly showed almost similar impact absorbed energy to composite. From the observation of microstructure, it was deduced that the bi-materials was preferentially fractured through micro-interface between matrix and composite in the vicinity of macro-interface.