ORNL-1771 - Oak Ridge National Laboratory

ANP QUARTERLY PROGRESS REPORT
Ceramics in Various Mediums
Static corrosion screening tests of three ceramic
oxides and one carbide (A1203, MgAI,O,, calcium-
stabilized ZrO,, and sic) were mode in a vacuum
atmosphere at l5OO0F for 100 hr in each of four
med i urns: sod ium, NaF-ZrF,-UF, (53.5-40-6.5 molk
%), lithium, and lead, A fourth ceramic oxide was
tested under the same conditions in sodium and in
NaF-ZrF,-UF, (53.5-40-6.5 mole %). The A120,
and MgAI,O, test pieces were cut froin single,
synthesized crystals; the Mg0 test pieces were
cleaved from a single, synthesized crystal. The
nominal dimensions of the test pieces and the re-
94
sults of the tests are given in Table 6.5. Powder
x-ray examinatians were made of the specimens
that were the least corrosion resistant in each
medium, and the results are summarized in Table
6.6.
The Sic specimens were, in general, the most
resistant to corrosion, and the AI,O, specimens
were the next most resistant. These single-run
screening tests are qualitative, and the results
should be used with caution. Larger specimens
are to be tested so that more accurate data can be
obtained and metallographic examinations and
chemical analyses can be made.
TABLE 6.5. SUMMARY OF STATIC TESTS OF CERAMICS IN VARIOUS ~ ~ AT 1500°F ~ FOR ~ 100 hr I ~ M ~
Thickness
Material Tested Change
(a)
A1203n - 0.5
Sicb -0.9
M~AI~O," 0.0
Zr02 (GO' stabilized) +8.6
MgOC -0.5
A1203
Zr02 (CaO stabilized)
Mg 0
A1203
Weight
Change
( %
Tested in Sodium
Re marks
-0.9 Specimen changed from a colorless transparent state to a
white semitransparent state; a small crack appeared an
an edge
Specimen essentially unaltered; brighter and cleaner;
small part of disk edge broken off
Originally colorless transparent specimen almost com-
pletely changed to a black state; chipped slightly on
one edge
Specimen changed from light buff to blue-black; edge
chipped
-0.1 Specimen unaltered except for color change from color-
less to light blue-gray
Tested in NaF-ZrF4-UF4 (53.5-40-6.5 mole W)
-3 1 Specimen broken and covered with fluoride mixture;
brown-red interface present between the fluoride mix-
ture and the specimen
- 1.8 Specimen broken; recovered pieces appeared to be un-
attacked
Recovered portion of specimen (more than one-half)
covered with fluoride mixture and apparently com-
pletely altered
No visible trace of specimen found
No visible trace of specimen found
Test.ed in Lithium
No visible trace of specimen found