Nondestructive method for chemically machining crucibles or molds from their enclosed ingots and castings

Patent · Tue Jan 01 00:00:00 EST 1991

OSTI ID:867923

Stout, Norman D ^[1]; Newkirk, Herbert W ^[1]

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1. Livermore, CA

An inventive method is described for chemically machining rhenium, rhenium and tungsten alloy, and group 5b and 6b crucibles or molds from included ingots and castings comprised of oxide crystals including YAG and YAG based crystals, garnets, corundum crystals, and ceramic oxides. A mixture of potassium hydroxide and 15 to 90 weight percent of potassium nitrate is prepared and maintained at a temperature above melting and below the lower of 500 degrees centigrade or the temperature of decomposition of the mixture. The enveloping metal container together with its included oxide crystal object is rotated within the heated KOH-KNO.sub.3 mixture, until the container is safely chemically machined away from the included oxide crystal object.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 5035769
• OSTI ID: 867923
• Country of Publication: United States
• Language: English

Related Subjects

nondestructive
method
chemically
machining
crucibles
molds
enclosed
ingots
castings
inventive
described
rhenium
tungsten
alloy
5b
6b
included
comprised
oxide
crystals
including
yag
based
garnets
corundum
ceramic
oxides
mixture
potassium
hydroxide
15
90
weight
percent
nitrate
prepared
maintained
temperature
melting
below
500
degrees
centigrade
decomposition
enveloping
metal
container
crystal
rotated
heated
koh-kno
safely
machined
nondestructive method
ceramic oxides
potassium nitrate
weight percent
ceramic oxide
potassium hydroxide
degrees centigrade
inventive method
metal container
tungsten alloy
oxide crystals
chemically machining
oxide crystal
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