SOLUBILITY OF NITROGEN IN LIQUID CHROMIUM

Solubility of nitrogen in liquid chromium has been measured in the tem perature range from 1870 degrees C to 2150 degrees C and at the nitrog en pressure in a gas phase from 1 to 25 atm. Measurements were realize d by means of leviation melting at the cooling rate of a sample equal to 10(3)-10(4) K.s(-1). By extrapolation of the results of experimenta l tests to the point P-N2-->0, the values of the equilibrium constant in the system: liquid chromium - nitrogen gas phase were determined fo r different temperatures. The reaction of the dissolution of nitrogen in liquid chromium is an exothermic process which is confirmed by the sign and the value of the dissolution heat determined using Van't Hoff equation for the temperature relationship of the equilibrium constant K-N(Cr). The activity coefficient of nitrogen f(N) strongly depends o n nitrogen concentration in the liquid chromium which suggests that th e Cr-N system is not governed by Sievert's law. With the increase of t emperature the influence of nitrogen concentration decreases, and the intensity of this influence can be estimated by means of the self inte raction parameter e(N)((N)) established in this work. All relationship s derived under the scheme of the author's own research were compared with literature data. The quantitative thermodynamic characteristics o btained on the basis of the experimental results of the work allowed t o derive equations which give the possibility of a calculation of nitr ogen solubility in liquid chromium as depending on metal temperature a nd nitrogen pressure up to hyperbaric conditions. For these reasons th ey can be useful in designing steelmaking technologies of modern high nitrogen steels which are recently intensively developed.