Method for the manufacture of doped quartz glass

Patent metadata

Field	Value
Publication number	US-2016016839-A1
Application number	US-201514804673-A
Country	US
Kind code	A1
Filing date	Jul 21, 2015
Priority date	Jul 21, 2014
Publication date	Jan 21, 2016
Grant date	—

Abstract

One aspect relates to a method for the manufacture of doped quartz glass. Moreover, one aspect relates to quartz glass obtainable according to the method including providing a soot body, treating the soot body with a gas, heating an intermediate product and vitrifying an intermediate product.

First claim

What is claimed is:

1 . A method for the manufacture of doped quartz glass, comprising:
a) providing a soot body, whereby the soot body has a mean density in the range of 18 to 30% relative to the relative density of quartz glass; b) treating the soot body with a gas comprising a fluorine-containing compound in a process chamber while forming a fluorinated intermediate product (A), whereby the mean density of intermediate product (A) increases by maximally 30% relative to the mean density of the soot body in step a); c) heating fluorinated intermediate product (A) to a temperature in the range of 950 to 1,150° C. while forming a fluorinated intermediate product (B), whereby the mean density of fluorinated intermediate product (B) is maximally 80% of the relative density of quartz glass; and d) vitrifying the fluorinated intermediate product (B) in a process chamber, whereby the pressure inside the process chamber is lower than the pressure outside the process chamber, while forming the doped quartz glass.

2 . The method according to claim 1 , whereby the mean density of fluorinated intermediate product (B) is maximally 60% of the relative density of quartz glass.

3 . The method according to claim 1 , characterized in that the fluorine-containing compound is selected from the group consisting of F 2 , SiF 4 , CF 4 , C 2 F 6 , SF 6 , C 3 F 8 , NF 3 , ClF 3 , BF 3 , and fluoro-chloro hydrocarbons.

4 . The method according to claim 1 , characterized in that the fraction of fluorine-containing compound in the gas is 15 to 100 vol. % or 60 to 100 vol. %, each relative to the total volume of the gas.

5 . The method according to claim 1 , characterized in that the treatment of the soot body in step b) takes place at a temperature in the range of 700 to 1,100° C.

6 . The method according to claim 1 , characterized in that the vitrification temperature in step d) is in the range of 1,200 to 1,500° C. or 1,250 to 1,350° C.

7 . The method according to claim 1 , characterized in that the mean density of the fluorinated intermediate product (B) is 40 to 80% or 50 to 60%, of the relative density of quartz glass.

8 . The method according to claim 1 , characterized in that the soot body is dried in step a) at a temperature in the range of 700 to 1,100° C. by thermal and/or chemical means.

9 . The method according to claim 1 , characterized in that the vitrification in step d) takes place in a second process chamber that differs from the first process chamber, in which steps b) and c) are performed.

10 . The method according to claim 9 , characterized in that the fluorinated intermediate product (B) is subjected to another drying step in the second process chamber before vitrification, whereby the drying takes place at a temperature in the range of 700 to 1,200° C.

11 . The method according to claim 1 , further comprising:
a) providing a soot body, whereby the soot body has a mean density in the range of 18 to 30%, relative to the relative density of quartz glass; a-1) drying the soot body at a temperature in the range of 700 to 1,050° C.; a-2) as an option, chemically drying the soot body at a temperature in the range of 700 to 1,050° C. in the presence of a chlorine-containing gas; b) treating the soot body with a gas comprising a fluorine-containing compound in a first process chamber while forming a fluorinated intermediate product (A), whereby the mean density of intermediate product (A) increases by maximally 30%, relative to the mean density of the soot body in step a); c) heating the fluorinated intermediate product (A) to a temperature in the range of 950 to 1,150° C. while forming a fluorinated intermediate product (B), whereby the mean density of the fluorinated intermediate product (B) is maximally 80%, or maximally 60%, of the relative density of quartz glass; c-1) as an option, chemically drying the fluorinated intermediate product (B) at a temperature in the range of 700 to 1,100° C. in the presence of a chlorine-containing gas; c-2) transferring the fluorinated intermediate product (B) into a second process chamber; c-3) as an option, heating the fluorinated intermediate product (B) to a temperature above 1,000° C., or 1,000 to 1,200° C., whereby the pressure inside the process chamber or is lower than the pressure outside the process chamber; d) vitrifying the fluorinated intermediate product (B) in the second process chamber, whereby the pressure inside the process chamber is lower than the pressure outside the process chamber, while forming the doped quartz glass.

12 . The method according to claim 1 , characterized in that the second process chamber is a vitrification furnace, or a multi-chamber sintering furnace.

13 . A method for the manufacture of doped quartz glass, comprising:
providing a soot body, the soot body comprising a mean density in the range of 18 to 30% relative to the relative density of quartz glass; treating the soot body with a gas comprising a fluorine-containing compound in a process chamber while forming a first fluorinated intermediate product, the mean density of the first fluorinated intermediate product increasing by maximally 30% relative to the mean density of the provided soot body; heating the first fluorinated intermediate product to a temperature in the range of 950 to 1,150° C. while forming a second fluorinated intermediate product, the mean density of the second fluorinated intermediate product being maximally 80% of the relative density of quartz glass; and vitrifying the second fluorinated intermediate product in a process chamber, the pressure inside the process chamber being lower than the pressure outside the process chamber, while forming the doped quartz glass.

14 . Doped quartz glass that is obtained according to a method comprising:
a) providing a soot body, whereby the soot body has a mean density in the range of 18 to 30% relative to the relative density of quartz glass; b) treating the soot body with a gas comprising a fluorine-containing compound in a process chamber while forming a fluorinated intermediate product (A), whereby the mean density of intermediate product (A) increases by maximally 30% relative to the mean density of the soot body in step a); c) heating fluorinated intermediate product (A) to a temperature in the range of 950 to 1,150° C. while forming a fluorinated intermediate product (B), whereby the mean density of fluorinated intermediate product (B) is maximally 80% of the relative density of quartz glass; and d) vitrifying the fluorinated intermediate product (B) in a process chamber, whereby the pressure inside the process chamber is lower than the pressure outside the process chamber, while forming the doped quartz glass.

15 . The doped quartz glass according to claim 14 , characterized in that the quartz glass comprises further dopants aside from fluorine, whereby the doping agent is selected from the group consisting of Al 2 O 3 , Yb 2 O 3 , Er 2 O 3 , NbO 2 , TiO 2 , Ce 2 O 3 , Y 2 O 3 as well as mixtures thereof.

16 . The doped quartz glass according to claim 14 , characterized in that the fluorine concentration in the doped quartz glass is 5,000 to 20,000 ppm, or 8,000 to 18,000 ppm, each relative to weight fractions.

17 . Use of the doped quartz glass as one of an optical component, fiber pre-mold and as part of an optical fiber, the doped quartz glass being obtained according to a method comprising:
a) providing a soot body, whereby the soot body has a mean density in the range of 18 to 30% relative to the relative density of quartz glass; b) trea

Assignees

• Heraeus Quarzglas

Inventors

• Schwerin Malte
• Trommer Martin
• Zwarg Steffen

Classifications

• C03B2201/42

  doped with titanium · CPC title

• C03B19/066 Primary

  for the production of quartz or fused silica articles (other processes specially adapted for the production of quartz or fused silica articles C03B20/00) · CPC title

• C03B2201/32

  doped with aluminium (C03B2201/36 takes precedence) · CPC title

• C03B37/01453

  for doping the preform with flourine · CPC title

• C03B2201/40

  doped with transition metals other than rare earth metals, e.g. Zr, Nb, Ta or Zn · CPC title