Patent ID: 9051203
Filing Date: 2015-06-09
Classification: C03B,C03C

Abstract:
1. A black synthetic quartz glass with a transparent layer, comprising: a black quartz glass portion; a transparent layer quartz glass portion; and an interface between the black quartz glass portion and the transparent layer quartz glass portion, the black synthetic quartz glass being produced by a production method comprising: a black quartz glass preparing step of preparing a black quartz glass portion by subjecting a silica porous glass body containing a hydroxy group to a gas-phase reaction in an atmosphere of a volatile organosilicon compound at a temperature of 100° C. or more and 1,200° C. or less, and after the reaction, firing the resultant at a temperature of 1,200° C. or more and 2,000° C. or less; a transparent layer preparing step of coating the black quartz glass portion with a transparent layer material, followed by heating treatment, wherein: the transparent layer preparing step comprises coating the black quartz glass portion with silica slurry, performing heating treatment in an oxidizing atmosphere in a temperature region of 300° C. to 1,200° C., and keeping the resultant within a temperature range of 1,300° C. to 2,000° C. and a pressure range of 0.001 to 1.0 Mpa to perform sintering; and the silica slurry uses silica particles each having an average particle diameter of 0.1 μm to 100 μm and has a concentration of silica of 50% to 95% and a concentration of a cellulose derivative of 0.05% to 10%, wherein: the black quartz glass portion comprises a black synthetic quartz glass which: the transparent quartz glass portion has characteristics of: