| Co-Investigator(Kenkyū-buntansha) |
TUJIKAMI Tetsuya RYUKOKU UNIV., SCI. & TECH., ASSIST.PROF., 理工学部, 助手 (80243179)
NISHIHARA Hironori RYUKOKU UNIV., SCI. & TECH., PROF., 理工学部, 教授 (90107441)
KOIZUMI Mitsue RYUKOKU UNIV., SCI. & TECH., PROF., 理工学部, 名誉教授 (80029826)
AOI Yoshifumi RYUKOKU UNIV., SCI. & TECH., RESEARCH ASSOCIAT., 理工学部, 助手 (70298735)
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| Research Abstract |
SELF-PROPAGATING HIGH TEMPERATURE SYNTHESIS (SHS) process in which at least one of the reactants is a solid, so-called combustion synthesis, has been gradually received attention from materials scientists. The products of these "solid flames" are technologically important materials such as structural ceramics with high melting temperature, intermetallics and the composites. Solid combustion reaction are generally accompanied by the release of a large amount of heat. In reactions that are sufficiently exothermic, the heat liberated is adequate to sustain the reactions by the rapid propagation of the combustion front without further addition of energy. The process are characterized by a high generated temperature (e.g., 2000 to 4000K), a fast-moving combustion wave front (e.g., 0.1 to 25 cm/sec), and extremely high heating (e.g., 10ィイD14ィエD1 to 10ィイD16ィエD1 K/sec) and cooling rates. The advantages of SHS process include high purity of products, low energy and short-time requirements, and
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relative simplicity of the process. SHS products are generally powdery of porous. But the highly dense form can be also fabricated using a combination technique of this process and an external pressure such as hot press, hot isostatic press (HIP), pseudo-HIP (P-HIP), explosive consolidation, and high-velocity forging. The objective of this research is to understand physico-chemically an effect of quick heat generating and subsequent quenching on the products, and to control the relaxation of non-equilibrium state of materials during the SHS process, and to synthesize novel new materials by this process. This research is divided to three portions. First is to make clear the formation mechanism of materials through the rapid heating and cooling by the dynamical analysis of the process. Second is to synthesize the covalent-bonded material containing only light elements and the materials including some bonding types in themselves. Third is to suppress the relaxation of non-equilibrium state of the materials, such as a graphitization of diamond, by applying the high non-equilibrium thermal process. For three years to perform this project, we could understand the physico-chemically the SHS process and synthesize several novel materials by the process. Less
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