Patent ID: 7708827

Claim:
A replaceable wear insert, comprising: a substantially bowl-shaped part of expanded graphite manufactured by the following steps: placing the expanded graphite in a compression mold formed of at least two parts having molding surfaces substantially defining a bowl shape with a geometry matching a geometry of an outer surface of a quartz glass crucible for which the wear insert is provided; closing the compression mold with a pressure of 10 to 100 Mpa to produce a substantially bowl-shaped compressed and molded part; removing the compressed and molded part from the compression mold and placing the compressed and molded part in another mold made of temperature-resistant material and having the same, substantially bowl-shaped geometry as the molding surfaces; and treating the compressed and molded part at over 2000° C. in the other mold in a halogen-containing atmosphere, cleaning and embrittling the substantially bowl-shaped compressed and molded part; said substantially bowl-shaped part containing less than 500 ppm of ash constituents; the replaceable wear insert not being bonded to a crucible, having a substantially uniform wall thickness and being adapted to be inserted in a graphitized support crucible for protecting the graphitized support crucibles against oxidative attack by quartz glass crucibles and acting as a sacrificial layer during semiconductor technology processes at temperatures exceeding 500° C.