METHOD FOR DETERMINING CRYSTALLIZATION TEMPERATURE OF HIGH-TEMPERATURE MELT

摘要

PURPOSE:To make exact measurement of the crystallization temp. of a high-temp. melt by determining the data on the viscosity and temp. when the temp. of the melt is dropped and determining the crystallization temp. from the viscosity-temp. characteristic in a region inclusive of the viscosity-temp. characteristic and solidification point in a molten state. CONSTITUTION:A material to be subjected to viscosity measurement is charged from a supplying device 13 into a crucible 11 and a control signal is outputted from an arithmetic control part 31 to a furnace controller 14 to heat and melt the material to be subjected to the viscosity measurement and to heat the melt thereof up to the highest temp. among the temps. at which the viscosity is to be measured. A viscosity measuring instrument 2 is then lowered and the level of the melt is measured while the temp. is dropped and while an oscillation piece 24 is oscillated at the resonance oscillation frequency. The amplifier of the piece 24 in the air is measured and the viscosity of the melt is measured by immersing the piece 24 into the melt down to the prescribed depth. The viscosity y-temp. x characteristic is then determined. The temp. tb at the intersected point Q of the characteristic curves y=A1x+B1 and y=A2x+B2 of both the measurements id determined as the crystallization temp.