Patent ID: 8733127
Filing Date: 2014-05-27
Classification: C03B,Y02P

Abstract:
1. A method for producing a silica container comprised of at least a silica as its main component and arranged with a silica substrate having a rotational symmetry, wherein the method comprises: preparing a powdered substrate's raw material, comprised of silica particles, for forming the silica substrate; forming a preliminarily molded silica substrate, comprising feeding the powdered substrate's raw material to an inner wall of a carbon-made outer frame having a rotational symmetry and aspiration holes arranged splittingly in the inner wall while rotating the outer frame thereby preliminarily molding the powdered substrate's raw material to an intended shape in accordance with the inner wall of the outer frame; forming the silica substrate, comprising degassing the preliminarily molded silica substrate by aspiration from an outer peripheral side through the aspiration holes formed in the outer frame while charging from an inner peripheral side of the preliminarily molded silica substrate a reducing gas containing more than 10% by volume of an H after forming the silica substrate, forming an inner layer comprised of a transparent silica glass on an inner surface of the silica substrate by spreading from inside the silica substrate a powdered inner layer's raw material comprised of crystalline silica and having a higher percentage of silica content by weight than the powdered substrate's raw material while heating from inside the silica substrate by a discharge-heat melting method.