湿式法によるマグネタイトの磁気的性質
FeO-Fe2O3系鉄酸化物の磁性に関する研究 (第2報)
1975 年 91 巻 1044 号 p. 73-76
詳細
1975 年 91 巻 1044 号 p. 73-76
The artificial magnetite obtained by wet method is formed by the following chemical reaction._??_
The magnetite obtained by simultaneous precipitation from the mixed solution of ferrous and ferric ion (1: 2) does not show the magnetic transformation at low temperature (-160°C or thereabout), and it is spontaneously oxidized in air. In this study, it was found that the spontanious oxidation of the precipitated magnetite in air was prevented by adding PVA into the magnetite suspension immediately after the formation of it. Nevertheless, so far as it is formed at the temperature lower than 100°, the magnetite did not show the low temperature magnetic transformation.
When the precipitated magnetite is aged in the solution at the temperature 150°C-250°C, the transformation was observed on it. The magnetization of it increased gradually with the raise of the aging temperature.
It was observed by X-ray diffraction that any sample mentioned above changed into magnetite and α-hematite by heating at 700°C in vacuum.
