著者

野村 勁 藤井 欽二郎

出版者

公益社団法人日本セラミックス協会

雑誌

窯業協會誌 (ISSN:18842127)

巻号頁・発行日

vol.77, no.888, pp.271-277, 1969-08-01

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The weight loss in nitrogen atmosphere of compact mixed powders of MgO and carbon at temperatures 1400°-1800°C was followed thermogravimetrically.<br>At any given temperature, the reaction proceeded as a first order reaction (activation energy, 43.8kcal/mole) in an early stage, and zero order reaction followed (53.8kcal/mole). It is considered that the zero order reaction is the characteristic of the reaction of this system, and it will be explained as the effusion of gas evolved in the compact from the surface pores at constant rate (1.3mg⋅cm^-2⋅min^-1 at 1700°C) irrespective of mixing ratio, shaping pressure, or sample weight. The partial pressure of gas in the compact was obtained from the Knudsen effusion equation. For 1700°C, 4.24×10^-6 atm was found, and it corresponds to the vapor pressure of MgO at the same temperature.