Osamu Odawara1, Masao Shiraishi2, Jun Ikeuchi1, Yasumasa Ishii3, Hiroshi Yamasaki3 and Mikio Sato3
1Government Industrial Research Institute, Tohoku, Sendai
Researches on a ``Centrifugal-Thermit Process'' are extended to the development of 5.5 m long metal-ceramic composite pipes. In the process of the development, it is confirmed that the thermit reaction proceeds rapidly to produce the composite pipes of homogeneous quality in the direction of pipe length by igniting only a part of reactant under the conditions of proper amount of thermit powders and proper centrifugal force. This fact is a great advantage in the production of long composite pipes. For producing the composite pipe of much higher quality, the propagation mechanism of thermit reaction should be investigated in more detail from the fundamental point of view.
In the present work, the characteristics of thermit reaction are investigated by measuring propagation patterns of reaction in the pipes with various powder densities and shapes. The propagation patterns of reaction in a Centrifugal-Thermit Process are also measured by means of a radio (FM)-telemeter technique.
The propagation rate of the thermit reaction is inversely proportional to the thermit powder density. If the reaction is applied to a hollow body, it propagates along the inner surface first and into the layer of the reactant subsequently. It is concluded that the Centrifugal-Thermit Process proceeds along the inner surface of the hollow body first and then into the layer in the radial direction resulting in producing the composite pipes of homogeneous quality.
centrifugal-thermit process, thermit reaction, propagation of reaction, hollow body, gaseous reaction, radio-telemeter
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