# US 8,783,069 B2 · Process for producing a quartz glass cylinder and also support for carrying out the process

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- Number: US 8,783,069 B2
- Document ID: US8783069B2
- Status: Granted
- Kind: B2
- Application number: 13/508,783
- Filed: 2010-09-14
- Published: 2012-09-13
- Granted: 2014-07-22
- Earliest claimed: 2009-11-09
- Assignees: Heraeus Quarzglas GmbH & Co. KG
- Applicants: Anke Schuster; Rene Sowa; Martin Trommer; Udo Peper
- Inventors: Anke Schuster; Rene Sowa; Martin Trommer; Udo Peper
- Web page: https://patentgrep.com/patent/US8783069B2

## CPC

- C03B 19/1492: {Deposition substrates, e.g. targets}
- C03B 37/01493: {Deposition substrates, e.g. targets, mandrels, start rods or tubes}
- Y10T 428/22: Nonparticulate element embedded or inlaid in substrate and visible
- Y10T 428/2918: including free carbon or carbide or therewith [not as steel]
- C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

In a known process for producing a quartz glass cylinder, a porous soot tube, which is sintered to form the quartz glass cylinder, is produced by depositing SiO2 particles on an outer cylindrical surface of a support, which rotates about the longitudinal axis thereof and has a layer of silicon carbide (SiC layer). In order on this basis to specify a support having a high resistance to fracture, which firstly can easily be removed and which secondly presents a low risk of contamination for the soot body, the invention proposes that the SiC layer is treated at a high temperature in an oxygen-containing atmosphere before the SiO2 particles are deposited, in such a manner that an SiO2 protective layer having a thickness of at least 0.1 μm is produced by oxidation.

## Claims

### Claim 1

A method for producing a quartz glass cylinder, said method comprising
producing a porous soot tube by depositing SiO2 particles on a cylinder jacket surface of a support rotating about a longitudinal axis thereof and having a SiC layer, and
sintering the soot tube so as to form the quartz glass cylinder, and
treating the SiC layer prior to deposition of the SiO2 particles at a high temperature in an oxygen-containing atmosphere such that a SiO2 barrier layer with a thickness of at least 0.1 μm is produced by oxidation.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the SiC layer consists essentially of a silicon infiltrated silicon carbide (SiSiC).

### Claim 3 (depends on 1)

The method according to claim 1, wherein the treatment in oxygen-containing atmosphere comprises annealing the support in a furnace or heating the support using an oxygen- or hydrogen-containing burner flame at a temperature of at least 1000° C.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the SiO2 barrier layer is produced with a thickness in the range of 1 μm to 10 μm.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the SiO2 barrier layer contains cristobalite.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the SiO2 barrier layer comprises layer portions of amorphous SiO2.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the treatment in oxygen-containing atmosphere comprises annealing the support in a furnace or heating the support using an oxygen- or hydrogen-containing burner flame at a temperature of at least 1200° C.