Surface Tension and Wettability of Liquid Fe-16 mass%Cr-S Alloy with Alumina

Abstract

The surface tension and wettability of liquid Fe-16 mass%Cr-S alloy with alumina substrate at 1823 K and the temperature dependence of surface tension of liquid Fe-16 mass% Cr-S alloy in the temperature range of 1808-1883 K were measured using the sessile drop technique. The surface tension and contact angle of liquid Fe-16 mass%Cr-S alloys with alumina substrate decreased markedly with increasing sulphur concentration in the alloys. The variation of surface tension of liquid Fe-16 mass% Cr-S alloys with sulphur activity can be described by the following equation: σ_1g=1640−182ln(1+157a_S) (mass% O=0.0037-0.0075, mass% S ≤ 0.195) (mN/m). The interfacial tension between liquid Fe-16 mass% Cr-S alloys and alumina substrate, calculated using Young’s equation, can be expressed by the following equation: σ_s1=2170−220ln(1+237a_S) (mass% O=0.0037-0.0075, mass% S ≤ 0.195) (mN/m). The work of adhesion between liquid Fe-16 mass% Cr-S alloys and alumina had a tendency to increase with increasing sulphur concentration. The temperature coefficient of surface tension, dσ⁄dT, for Fe-16 mass% Cr-S system in the temperature range of 1808-1883 K increased with increasing sulphur concentration, and changed from negative to positive value when the sulphur concentration exceeded 20 mass ppm.