ORNL-1816 - the Molten Salt Energy Technologies Web Site

ANP QUARTERLY PROGRESS REPORT
TABLE 6.5. RESULTS OF STATIC TESTS OF BRAZING ALLOYS ON TYPE 304 STAINLESS STEEL T-JOINTS
IN NaF-ZrF4-UF4 (53.5-40-6.5 mole %) AND IN SODIUM AT 15OO0F FOR 100 hr
Brazing Alloy Weight Weight
Compos it ion Bath Change* Change Metallographic Notes
(wt %) (9) (%I
Alloy A-16 NaF-ZrF4-UF, -0.0003 -0.042 Braze fillet unattacked
23 P, 77 Ni Sod i um -0.0009 -0.135 Subsurface voids in braze fillet to a depth
of 5 mils; attack confined to Ni3P phase
Alloy C-27 NaF-ZrF4-UF, 0 0 No attack
9.6 P, 2.75 Cr, 88.6 Ni Sodium -0.0006 -0.086 Subsurface voids to a depth of 5 mils;
Ni3P phase attacked
Alloy C-29 NaF-ZrF4-UF, +0.0011 +0.180 No attack
10.2 P, 13 Cr, 76.8 Ni Sodium +0.0004 +0.054 Less than 0.5 mil of small subsurface
voids
Alloy B-11 NaF-ZrF4-UF, -0.0006 -0.082 Braze fillet attacked to a depth of 1 mil
10.8 P, 9.2 Si, 80 Ni in several areas
Sodium 0 0 Subsurface voids in fillet to a depth of
4 mils
Alloy J-10
9 p, 15 Fe, 4.5 Cr, 71.5 Ni
NaF-ZrF4-UF
4
+0.0007 +0.153 Small subsurface voids in braze joint to a
depth of 0.5 mil
Sodium -0.0004 -0.067 Subsurface voids to a depth of 7 mils;
Ni3P removed from fillet zones
Alloy H-10 NaF-ZrF4-UF, +0.0036 +0.730 Maximum attack was 0.5 mil in the form of
10 p, 4.3 Mo, 86.7 Ni small subsurface voids
Sod i um -0.0006 -0.108 Subsurface voids in braze fillet to a depth
of 19 mils
Alloy 1-10 NaF-ZrF4-UF, +0.0008 +0.112 No attack
11.6 P, 6.25 Mn, 82.15 Ni Sodium -0.0018 -0.346 Subsurface voids in braze fillet to a depth
of 11 mils
Alloy D-11 NaF-ZrF4-UF4 +0.0015 +0.304 No attack
9.9 p, 11.3 Fe, 78.8 Ni Sodium +0.0006 +0.108 Subsurface voids in braze fillet to a depth
*Weight change data include brazing alloy and base material of joint.
fillet of the specimen tested at llOO°F and very
few diffusion voids were present. However, as
may be seen in Fig. 6.8, the specimen tested at
1500'F showed a 6-mil surface attack and also
several small interfacial voids.
Additional static corrosion tests are being con-
ducted on many of these same brazing alloys in
sodium in order to evaluate their suitability for
use as a back braze for the sodium-to-fused fluoride
heat exchangers.
82
of 25 mils
Screening Tests of Carbides
Specimens of carbides of boron, titanium, zir-
conium, and chromium were tested in static sodium,
I ithium, and NaF-ZrF,-UF, (53.5-40-6.5 mole %)
at l5OO0F for 100-hr periods. The measured densi-
ties and apparent porosities of the specimens and
the results of the corrosion tests are given in
Table 6.8. The data indicate that Tic and Cr,C,
had the best resistance to corrosion in each of the
mediums; Figs. 6.9 and 6.10 show the typical