A process for the preparation of a pipe made of quartz glass, tubular semi-finished product made of porous quartz glass and the use of the same

摘要

In the case of a known method for the production of a pipe made of quartz glass by flame hydrolysis of a silicon-containing starting component are sio particles containing φ φ 2 produced, these with the formation of a soot tube with a porous soot wall with a predetermined radial soot - sealing profile deposited on a carrier, the soot tube in a chlorine-containing atmosphere and then vitrified. In order to modify this process so that, even after the dehydration treatment under a chlorine-containing atmosphere a predetermined radial refractive index distribution is obtained, it is proposed according to the invention that, in an inner region of the soot wall a higher density of at least 25% of the density of quartz glass, in an outer region of the soot wall a lower density and in a subsequent to the inside area transition region, a to the outer region is set back decreasing density. The inventive tubular semi-finished product is distinguished by a soot wall, which, in an inner region, a higher density of at least 25% of the density of quartz glass, in an outer region and a lower density, in a subsequent to the inside area transition region, a density decreases toward the outside.