| 摘要 |
A process for producing a single crystal is carried out by solidification from a melt using a triple-structure crucible (1). (1) comprises an outer cylinder (2), an inner cylinder (3) and an intermediate cylinder (4). (2) is made of a metal and its alloy, both of which have melting pts as high as 1500 deg.C or above such as W, Ta, Os, Mo, Ir, Ru, Rh and Pt( preferably Mo, W Ta). (3) is made of a high-melting pt ceramic material such as alumina, BN, AlN, BeO, CaF2, MgO, SiC, CeO2, ThO2, ZrO2, ZrSiO4, etc. or a carbon aceous materials such as graphite, pyrolytic graphite, vitreous carbon etc. (4) is made of quartz glass. The starting material is held in the inner cylinder which is sealed off and then placed in the intermediate cylinder. this is then hermetically sealed and inserted into the outer cylinder which is sealed off by welding. The crucible is heated to melt the starting material and to cause crystal growth. A powder having the same compsn as the starting material is preferably filled between the outer cylinder and the intermediate cylinder. |
