The Surface Energy of Iron-3% Silicon by Surface-Relaxation Measurements

Abstract

AbstractThe surface energy of iron-3% silicon alloy has been determined as 1940 ± 600 erg. cm−2 for the range 1075–1325° C by measuring the decay kinetics of multiple scratches on single crystals near (110) orientation during vacuum annealing. Mass transport occurred mainly by volume diffusion in the alloy. Surface-energy values from single scratches were higher by ∼ 20% than those from multiple scratches, probably because of inadequacies in the single-scratch analysis. Facets formed where the smoothed scratch profile contained the (110) plane at the highest temperature (1300° C) only and for the crystal nearest to (110) orientation. It was noted that extended striations formed on a single crystal near (100) orientation on annealing at 1200° C, in the direction for which a small surface tilt would expose the (100) plane. These observations suggest that the γ-plot has a deeper cusp at (100) than at (110) under the annealing conditions prevailing.