| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of evaluating silica powder, which enables precise prediction of easiness of crystallization of a vitreous silica crucible. <P>SOLUTION: The method of evaluating silica powder includes: a sample preparation step of preparing a vitrified sample by fusing silica powder at a fusing temperature of 1,700 to 1,900 °C, followed by cooling; a sample heat treatment step of retaining the sample for 30 minutes or more at a temperature of 1,400 to 1,750 °C, followed by cooling; and a sample evaluation step of evaluating a state of opacification of the sample after the sample heat treatment step. <P>COPYRIGHT: (C)2012,JPO&INPIT |
