Electric Resistivity of Molten Fe-C, Fe-Si, and Fe-C-Si Alloys

Abstract

The electric resistivity of molten Fe-C, Fe-Si, and Fe-C-Si alloys has been measured by the electrodeless, rotating field method. The results are summarized as follows.
(1) The resistivity of pure iron shows a rise of about 5% in the process of melting and thereafter a linear increase with increasing temperature up to 1625°C.
(2) For molten Fe-C alloys, the concentration range of measurement has been from 0.32-4.22%, the temperature range being up to 1500-1600°C.
(a) The resistivity increases linearly with an increase of temperature.(b) The resistivity isotherm increases fairly steeply but monotonously with rising carbon content.(c) The temperature coefficient of resistivity exhibits a rapid fall at a concentration between 0.32% and 0.92%, showing little change at higher concentrations.
(3) For molten Fe-Si alloys, the measurements have been made in the temperature range up to 1450-1580°C and in the whole concentration range.
(a) The resistivity of the alloys with silicon content of more than 30at% shows a fall in the process of melting.(b) The resistivity shows a linear dependency on temperature. But the temperature coefficient of the alloys with silicon content of more than about 50at% is negative, except that of pure silicon.(c) The resistivity isotherm shows a large positive deviation from the so-called additivity law.
(4) The resistivities of molten Fe-C-Si alloys with concentrations of 1 or 3% carbon and 2, 5, or 10% silicon have been measured in the temperature range up to 1450-1580°C with the result which is indicative of the possibility of the multiplying interaction of carbon and silicon on the resistivity of molteniron.