Thermodynamic Relation between Silicon and Aluminum in Liquid Iron

Reassessment of AlN(s)=<u>Al</u>+<u>N</u> Equilibration in Liquid Iron

“…The AlN formed in the melt was identified as a pure solid stoichiometric AlN by the XRD analysis. 5,6) Therefore, the activity of AlN is unity under the present experimental condition.…”

“…(7) using the present experimental data for the AlN solubility product in liquid iron at 1 823, 1 848 and 1 873 K together with the previous data determined in the authors' recent studies. [4][5][6] It is apparent from the figure that the data points determined at different nitrogen partial pressures and temperatures show excellent linear relationships. Therefore, using the values of and determined in the preceding section, the values of and logK AlN in Eq.…”

“…Detailed descriptions of the experimental apparatus and procedure are available in the authors' recent studies. [4][5][6] Five hundred grams of high purity electrolytic iron contained in an Al2O3 crucible was melted in the temperature range from 1 823 to 1 873 K by a high frequency induction furnace. After the melt temperature was reached at a desired value, Ar-10%H 2 gas was blown onto the melt surface at a high flow rate of ~5 000 ml/min for 2 h to deoxidize the iron melt.…”

“…A metal sample of about 10 g was extracted by a 4 mm ID quartz tube connected to a syringe (10 ml), and it was quenched rapidly in water within 2 s. The metal samples were carefully cut for the chemical analysis. In author's previous studies, [4][5][6] the detailed procedure for chemical analysis is available. Aluminum addition and sampling were repeated until a stable AlN layer was formed on the surface of the iron melt.…”

“…Therefore, in the present study, the values of , , and logKAlN were accurately determined over the temperature range from 1 823 to 1 973 K by combining new experimental data for the Al-N-AlN relations in liquid iron together with the authors' previous data. [4][5][6] …”