High Temperature Vaporization of the High Melting Point Oxides

,; ,

J. Korean Ceram. Soc. > Volume 15(2); 1978 > Article

Journal of the Korean Ceramic Society 1978;15(2): 72.

고융점 산화물에 대한 고온 증발

이홍림

연세대학교 공과대학 요업공학과

High Temperature Vaporization of the High Melting Point Oxides

ABSTRACT

The vapor pressure of the high melting point oxides, MgO, $Cr_2O_3$, and $MgCr_2O_4$ were measured over the temperature range 1300 to 175$0^{circ}C$ under vacuum <$10^{-5}$ torr by the Langmuir and the Knudsen method. The Langmuir vapor pressure was increased with elevating temperature and with increasing porosity of the specimen. The difference between the vapor preseures measured by the Langmuir and the Knudsen method was decreased with elevating temperature and the Langmuir vapor pressure finally reached the Knudsen vapor pressure at the melting point when extrapolated. The vapor pressure of other important oxides with high melting points, i.e., $Al_2O_3$, $ThO_2$, $Yb_2O_3$ and $Y_2O_3$ were cited from the references. The Langmuir and the Knudsen vapor pressure of these oxides also showed the same results, i.e., they showed the same value at their melting points.