Estimation of actual growth rate in the Bridgman growth of Tin Crystal by recording the temperature-time curves

摘要

It is shown through the use of tin crystal that the actual growth rate in the Bridgman growthprocess could be investigated by recording the temperature-time curves at given axial locations inthe melt-solid system. Variations of the growth rate in the seeded and unseeded growth processesof tin crystal have been examined and discussed. The results are summarized as follows.It is surmised for the seeded growth that the actual growth rate increased with the progressof solidification, and the average rate was 1.7 times the translation rate of the furnace. Theincrease of the growth rate may be related to the increase in solidified fraction of the melt. In thecase of the unseeded growth, the initial growth rate was ten to forty times the translation rate ofthe furnace but rapidly decreased to about four times that with the progress of solidification.Thus, it is thought that the growth in initial stage proceeds at a high speed independently of thetranslation rate of the furnace, resulting in a high growth rate compared to the seeded process