| Budget Amount *help |
¥8,100,000 (Direct Cost: ¥8,100,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1996: ¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1995: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
Systematic investigation has been done to synthesize non-oxidative functional materials by using flame CVD (Chemical Vapor Deposition) from 1975 to 1997. Formation of ultrafine GeO2 particles in a laminar diffusion flame of Oxygen-hydrogen was experimentally investigated first, and compared with that of SiO2. Tetraethylorthogermanium (TEOG) was used as Ge source. At the lower part of the flame with lean oxygen, the homogeneous uncleation of GeO ultrafine particles occurred. For low feed concentration, they completely sublimated during their ascending through higher temperature zone, and GeO2 ultrafine particles newly nucleated in the upper, oxygen rich, flame region. Most of Geo particles reached to the upper flame region for high feed concentration, and oxidized to Geo2 together with the inhomogeneous uncleation of GeO2. For the case of SiO2 formation, no sublimating phenomena were observed. Solid formation mechanism in a flame is strongly affected by feed concentration, temperature distribution and material itself.
Next, SiN ultrafine particles were synthesized in the same flame by introducing 1,1,1,3,3,3-hexamethyldisilasane (HMDS). SiN particles were sampled only when a sampling tube was inserted just above the reductive inner flame. It can be said that non-oxidative material can be synthesized by flame if we could apart them from oxygen rich, high temperature region of a flame.
It is necessary to utilize premixed flame to realize high producibility. First, we checked and confirmed the possibility of diamond film formation by using oxygen-acetylene premixed flame. Then, SiC thin film was synthesized by introducing HMDS in the flame.
At the final period of the term, we investigated the possibility of propane gas as a fuel. Once we obtained SiC whisker, however, we could not resynthesize the same material at present. The possibility of propane gas as a fuel source is still under investigation.
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