酸化チタンを含む溶融スラッグの電気伝導度 (I) : Na_2O-SiO_2-TiO_2 系
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概要
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In order to study the behaviour of TiO_2 in molten slags, the electrical conductivity of the Na_2O-SiO_2-TiO_2 system was measured. The measured range of composition was TiO_2 0∿35mol% at Na_2O/SiO_2=0.40, 0.50 and 0.61. The conductivity decreases smoothly with temperature. At constant temperature the conductivity remains almost unchanged for the slags containing TiO_2 less than 10mol%, but with more TiO_2 the conductivity decreases with increase of TiO_2. The conduction mechanism is ionic, and the mobile ion is Na^+. Ti ion cannot move, because the bonds Ti-O is strong owing to small ionic radius and large ionic valency. The molar electrical conductivity, which corresponds directly to the mobility of Na^+, was calculated. At the range of low TiO_2 contents Ti ions distort Si-O network, raising the mobility of Na^+, while at the range of high TiO_2 contents oxygen ions impede the conduction of Na^+, thus lowering the mobility of Na^+. The latter behaviour of TiO_2 is different from SiO_2 or Al_2O_3, because TiO_2 lowers viscosity of sodium-silicate contrary to SiO_2 and Al_2O_3. TiO_2 is amphoteric, and it behaves as basic oxide at low contents, while it is like an acidic oxide at high contents. For the series Na_2O/SiO_2=0.50 the conductivity of slags containing TiO_2 40∿50mol% was measured. In the conductivity-temperature curve an anomalous point appears in the neighbourhood of solidifying temperature, suggesting the behaviour of TiO_2 as a semi-conductor. It was summarized that the peculiar behaviour of TiO_2 would be ascribed to the following facts : (1) The bonds Ti-O are strong, and Ti ion has the strong action of "network distortion" (2) Ti is a transition metal, and TiO_2 is a typical semi-conductor.
- 社団法人日本鉄鋼協会の論文
- 1956-08-01