CRUCIBLE FOR SINGLE CRYSTAL

摘要

PURPOSE:To prevent deformation by load even if a crucible for a single crystal is exposed to a high temp. for a long time by reinforcing the outside circumferential surface at the top end of a bottomed cylinder made of platinum (alloy) with an annular ring made of an oxide-dispersed platinum alloy and providing a hanger for hanging the ring. CONSTITUTION:An annular ring 5 having the inside diameter equal to the outside diameter of a bottomed cylinder 1 consisting of platinum or a platinum alloy is welded to the circumferential surface 6 at the top end of said cylinder 1. The ring 5 is produced by dispersing oxide particles of high m.p. metals such as Ti and V in the compsn. having the same components as the components of the cylinder 1. Therefore, the coefft. of thermal expansion is the same and a weld zone 6 is kept free from the deformation owing to thermal expansion. Even if the load of the cylinder 1, the ring 5 and a raw material for a single crystal are exerted on the surface 6, the load near the hanger 2 is supported by the hanger 2 and the load of the part except the hanger 2 is supported by the ring 5 united together thereto; therefore, the crucible is not contracted.