Measurements of Surface Tension of Li_2B_4O_7·KNbO_3 Solution by Contour Curve Fitting Methods

A method for measuring the surface tension-Contour Curve Fitting Method, which is determined by digital video image processing of a sessile drop with using computer was discussed. The image of a sessile drop of Li2B4O7+KNbO3 formed on a BN plate was recorded on a digital video tape and converted into digital data of profile by using the technique of digital image acquisition and processing. The Segmented drop image was fitted with numerical solution of theoretical equations to determine a surface tension. The thermal and solute surface tension coefficients were given by the following forms respectively, rT(mN/m)=210+0.15(T-900℃), 900℃≤T≤ 1000℃ andγｃ(mN/m)=229-0．45(CKN-10wt%), 10wt%≤ CKN ≤30wt%.