We combined Field-Activated Combustion Synthesis(FACS) with mechanical pressure to produce dense WC-20 vol.%Co composite in one step. The hardness, the fracture toughness and the relative density of the dense WC-20 vol.%Co were investigated. Under the application of 60 MPa pressure and 3000A current on the reactants, the relative density of WC-20 vol.%Co composite was 99.4%. The fracture toughness and hardness were and respectively. The fracture toughness and hardness of WC-20 vol.%Co composite produced by FAPACS were lower than that of nanostructured composite, but similar to commercial ones. Therefore we concluded that the FAPACS method which can produce WC-20 vol.%Co within several minutes in one step is superior to conventional ones.

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.

금속기지 복합물은 구조용 재료로서 매우 우수한 성질을 지니고 있어 광범위하게 연구되어져 왔다. Al2O3와 SiC는 그들의 우수한 기계적 특성 때문에 일반적인 보강재로서 사용되어져 왔다. 그러나 이들 세라믹 보강재는 비싼 재조 비용 때문에 특별한 목적을 위해서만 한정되어 사용되어져 왔다. 본 연구에서는 우리는 Al 합금기지 복합물에서 SHS법에 의해 합성된 Al2O3-SiC 분말의 보강재로서의 응용 가능성을 살펴보았다. 또한 Al2O3단섬유를 Al기지 하이브리드 복합물에 적용하기 위하여 합성된 분말과 함께 첨가하였다. 25vol% 강화재의 복합물을 제조하기 위하여 용탕단조법을 사용하였다. 미세구조와 결정구조는 SEM, OM 그리고 XRD로 관찰하였고 압축시험과 마모시험으로 기계적인 성질들을 조사하였다.

ZrO2, B2O3 및 AI을 사용하여 SHS법에 의한 붕화지르코늄을 합성을 하고 산화철과 알루미늄 분말의 첨가가 합성물의 치밀화에 미치는 영향에 대하여 검토하였다. 합성물중에 존재하는 결정상은 대부분이 ZrB2와 α-AI2O3상이었다. 산화붕소와 알루미늄의 몰비가 1.0:3.3이상일 때 합성물의 치밀화는 크게 증가하였고, ZrB2 입자도α-AI2O3용융상과 더불어 조대하였다. 산화철 1목에 대하여 알루미늄을 1-3몰을 첨가한 것과 산화철 1.5몰에 대하여 알루미늄을 3몰 첨가시 α-AI2O3를 중심으로하는 슬라그상으로부터 용융상의 분이가 가능하였고, 이들 용융상에 존재하는 결정상은 ZrB2이외에 Fe, Fe2B, Zr2Fe상이었다. 용융상의 상대밀도는 산화철 1몰에 대하여 알루미늄을 1몰 첨가시 83.2%인 반면에 그 이상의 첨가량에 대해서는 치밀화는 크게 증가하여 알루미늄을 3몰 첨가한 경우 상대밀도는 93.7%로서 최대를 나타내었다.

자체연소반응법에 의하여 탄화붕소(B4C)를 합성함에 있어서 자체적으로는 반응이 이루어지지 않아서 간접점화법인 화학로법(Chemical Furnace)으로 합성을 하였으며, 성형압력과 몰비를 변수로 하여 연소온도 및 연소속도의 변화를 측정하였다. 성형밀도가 이론밀도의 70%에서 연소온도와 연소속도가 가장 높았으며, 몰비에 대한 영향은 표준비였을 때 연소온도와 연소속도가 가장 높았다. 그리고 성형밀도에 따른 입자의 크기변화는 성형밀도가 높을수록 입자의 크기는 작아졌으며 따라서 비표면적은 커졌다.

Silicon carbide powder was prepared from mixtures of Sangdong silica sand and carbon black by SHS (Self propagating High temperature Synthesis) method which utilizes magnesiothermic reduction of silica. In the powder preparation process, the reacted powder was leached by chloric acid to remove the magnesium oxide and was subsequently roasted to remove free carbon. The impurities were mostly eliminated by hot acid treatment. The resultant SiC powder showed the mean particle size of 0.22 and the specific surface area of . The SiC powder was mixed with 1 wt% of boron and of carbon to increase densification rate. The mixed powder was pressed and sintered pressurelessly at for 30 min in argon gas. The sintered body showed the hardness of and the fracture toughness, KIC of .

This study focused on enhancing the mechanical properties and thermal stability of bio-composites with natural agricultural residues and improving the interfacial adhesion between polymer and biodegradable agricultural residual waste fibers. To achieve this purpose, we proposed superheated steam (SHS) treatment method as a novel pre-treatment of fiber for improved of compatibility in polymer matrix. The use of SHS-treatment was investigated as a method for improving interfacial adhesion between agricultural residual waste fibers and polymer and with the goal of enhancing mechanical properties. We selected wheat straw fibers for agricultural waste fibers to improve the surface modification. Wheat Straw Fibers (WSF) was treated with SHS in order to modify its characteristics for bio-composite applications. Treatment was conducted at temperatures 200oC and 230oC for each 1 h. SHS-treated WSF was evaluated for its chemical composition, thermal stability, morphology and crystallinity. Thermal stability of the fibers was investigated using thermogravimetric analysis and found that the degradation temperature of the fibers is increased after of the SHS treatment. In addition, SHS treatment contained in the WSF reduce the rate of hemicellulose components. The WSF is polar nature of lignocellulose due to the presence of hydroxyl and carboxyl groups in cellulose and hemicellulose causes it to be incompatible with non-polar thermoplastics. SHS-treatment was found to be able to remove hemicellulose, which is the most hydrophilic and most thermally unstable component in WSF, since it has the lowest thermal resistance. Removal of hemicellulose makes the fiber less hydrophilic and this will potentially increase the compatibility of treated WSF and polymers and improves the mechanical properties and water resistance of composites.