The surface tension of Bi2O3-B2O3-SiO2 melts was measured using the ring method over the temperature range 973-1573 K. The composition and temperature dependences of the surface tension were investigated. The surface tension of Bi2O3-B2O3-SiO2 melts showed a maximum near 60-70 mol% Bi2O3 and decreased with increasing B2O3/SiO2 ratio at 1373K. By assuming a linear relationship between the surface tension and the Bi2O3 content of binary silicate melts, the surface tension factor of Bi2O3 was determined to be 211 mN m(-1) at 1373K. The surface tension values calculated using the surface tension factor of each single component showed the largest deviation from the measured values when the Bi2O3 content was around 50-60% and were dependent on the B2O3 content. The temperature coefficient of surface tension had positive values at low Bi2O3 contents (less than 30-40 mol%) and negative values at high Bi2O3 contents. (C) 2012 Elsevier B.V. All rights reserved.