SILICA VESSEL AND PROCESS FOR PRODUCTION THEREOF

摘要

Disclosed is a process for the production of a silica vessel which comprises both a base body that contains bubbles in the outer peripheral portion and an inner layer that consists of transparent silica glass and that is formed on the inner surface of the base body. The process comprises: preparing a base body-forming raw material powder that has a total concentration of Li, Na and K of 50wt.ppm or less and an inner layer-forming raw material powder that contains Ca, Sr and Ba in a total amount of 50 to 2000wt.ppm; forming a preform for the base body in a mold; forming a preform for the inner layer on the inner surface of the perform for the base body; and heating the thus-obtained composite preform in a gaseous atmosphere that contains hydrogen, helium, or a mixture of both in an amount exceeding 10vol% by an electric discharge heating-melting method from the inside of the composite preform to convert the outer peripheral portion of the preform for the base body into a sintered body and to convert the inner peripheral portion of the preform for the base body and the preform for the inner layer into a molten glass body. Thus, both a process by which a silica vessel with high dimensional accuracy and high heat resistance can be produced at a low cost and such a silica vessel are provide