Abstract
ENTHALPY CONTRIBUTION TO HEAT OF TRANSPORT
A. I. Ijomah* and L. N. Emenbolu
ABSTRACT
The heat of transport Q* was measured for carbon in Fe-32.5wt% Ni alloy for different carbon concentrations in regular solutions. The heat of solution of carbon in the iron-nickel-carbon system studied was determined from thermodynamic principles and graphical methods using literature data of the carbon solubility limit in the Fe-Ni-C system, and the activity formulation for the system as suggested by Natesan and Kassner. Our results suggest that the sign of Q* does not depend on whether or not an ideal solution is assumed. But the absolute value of the Q* does seem to depend on whether such results are obtained from the plot of In activity vs 1/T or In c vs 1/T for regular solutions. The difference from such absolute values strongly suggest the use of In activity vs the reciprocal of temperature plots for more reliable results. Barring the margin of error in the results of this and our previous work, the Q* values measured on the assumption of ideality conditions seem to contain contributions from the solute enthalpy.
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