Al2O3-SiC ceramic composites are produced using pressureless sintering, and their plasma resistance, electrical resistance, and mechanical properties are evaluated to confirm their applicability as electrostatic-discharge-safe components for semiconductor devices. Through the addition of Mg and Y nitrate sintering aids, it is confirmed that even if SiC content exceeded 10%, complete densification is possible by pressureless sintering. By the uniform distribution of SiC, the total grain growth is suppressed to about 1 μm; thus an Al2O3-SiC sintered body with a high strength over 600 MPa is obtained. The optimum amount of SiC to satisfy all the desired properties of electrostatic-discharge-safe ceramic components is obtained by finding the correlation between the plasma resistance and the electrical resistivity as a function of SiC amount.

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.

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.

Effects of liquid phase and reinforcing particle morphology on the sintering of Al-6 wt％Cu-10 vol％ or SiC particles were studied in regards to densification, structure and transverse rupture properties. The Al-Cu liquid phase penetrated the boundaries between the aluminum matrix powders and the interfaces with reinforcing particles as well, indicating a good wettability to the powders. This enhanced the densification during sintering and the resulting strength and ductility. Since most of the copper added, however, was dissolved in the liquid phase and formed a brittle phase upon cooling rather than alloyed with the aluminum matrix, the strengthening effect by the copper was not fully realized. Reinforcing particles of agglomerate type were found less suitable for the liquid phase sintering than solid type particles. and SiC particles protluced little difference on the sintering behavior but their size had a large effect. Repressing of the sintered composites increased density and bending properties but caused debonding at the matrix-particle interfaces and also fracturing of the particles.

Al2O3SiC particle was prepared was prepared by the self-propagting high temperature sYthesis(SHS) process from a mixture of SiO2, Al and C powders, The fabricated Al2O3SiC particle was applied to 2024Al/(Al2O3SiC)pcomposite as a reinforcement. Aluminum matix composites were fabricares by the powder extrusion method using the synthesized Al2O3SiC particle and commercial 2024Al powder. Theoptimum preparation conditions for Al2O3SiC partticle by SHS process were described. The influence of the Al2O3SiC voiume fraction on the mechanical was composite was also discussed. Despite adiabatic temperature was about 2367K, SHs reaction was completed not by itself, but by using pre-heating. Mean particle size of final particle synthesized was 0.73 m and most of the particle was smaller than 2m. Elastic modulus and tensile strength of the composite increased with increase the volume fraction of reinforcement but, tensile strength depreciated at 30 vol% of reinforcement.

Al2O3-SiC 화합물 분말이 SiO2, A1 그리고 C 분말들을 원료분말로 하여 SHS(self-propagating High-temperature Synthesis)법에 의해 제조되었다. 원료 분말에서의 몰비, 성형압력, 반응물의 초기온도의 영향이 생성물과 연소과정에 대해 연구되었다. SiO2/A1/C계의 자전연소합성은 낮은 연소온도 때문에 400˚C 이상으로 예열되어야 한다. 연소반응의 결과로서 최종생성물의 순도는 반응물의 순도보다 높았다. 이 계에서 SiO2:Al:C의 적당한 몰비는 3.0:4.0:6.0이었고, free carbon은 30min 동안 650˚C에서 배소함으로써 제거되었다. 본 연구에서 상압소결은 1700˚C에서 powder bed를 사용한 표본의 분해를 제어하고 치밀한 소결체를 얻는데 매우 효과적이었다. hot-pressing으로 생성된 소결체는 이론비교밀도의 약 98%이었다.

알루미나 매트릭스 복합재료를 AIZnMg(7075)-합금의 직접적인 용융산화를 통하여 제조하였다. 충전재료는 17μm 크기의 모서리가 둥근 연마재용 SiC 입자를 사용하였다. 산화촉진재 SiO2를 사용한 경우와 사용하지 않은 경우를 비교하였다. 매트릭스 형성 매카니즘과 반응거동을 온도와 SiO2사용량을 중심으로 연구하였으며, 얻어진 AI2O3/SiC/금속 복합재료의 미세구조를 관찰하였다.

Microwave pyrolysis of SF6 on alumina-based catalyst doped with cerium sulfate was investigated. Silicon Carbide (SiC) used as a microwave susceptor. The catalysts were characterized by X-ray diffraction (XRD) and the destruction and removal efficiency (DRE) of SF6 was evaluated by GC-TCD. We found that the optimal cerium content was 20wt% at microwave pyrolysis of SF6. The catalysts modified by cerium showed higher DRE at lower reaction temperature compared with original catalysts. The highest DRE of SF6 on CeA (20) was 80% at 600oC reaction temperature and the DRE was up to 95% when the reaction temperature over 700oC. It showed the alumina-based with cerium promotes the removal efficiency of SF6 at a mild reaction temperature. From XRD results, modified catalysts could be higher stability because of no transformation of the crystal phase after reaction.

Tetrafluoromethane(CF4) have been widely used as etching and chemical vapor deposition gases for semiconductor manufacturing processes. CF4 decomposition efficiency using microwave system was carried out as a function of the microwave power, the reaction temperature, and the quantity of Al2O3 addition. High reaction temperature and addition of Al2O3 increased the CF4 removal efficiencies and the CO2/CF4 ratio. When the SA30 (SiC+30wt%Al2O3) and SA50 (SiC+50wt%Al2O3) were used, complete CF4 removal was achieved at 1000℃. The CF4 was reacted with Al2O3 and by-products such as CO2 and AlF3 were produced. Significant amount of by-product such as AlF3 was identified by X-ray powder diffraction analysis. It also showed that the γ-Al2O3 was transformed to α-Al2O3 after microwave thermal reaction.