Activity of copper in solid Cu-Au alloys
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Alloy
C
Mn
Si
Cr
Ni
Co
Mo
W
Cb + Ta
Fe
Cu
N 155" DH 242t Hastelloy X ~ TD NiCr~t
0.06 0.03 0.09 0.011
1.35 0.08 0.58
0.31 0.95 0 57
21.07 19.26 21.57 21.85
19.16 Bal Bal Bal
19.92
2.72
2.41
1.13 1.27
Bat. 0.87 18.07
0.02
1.45
9.08
0.52
S
P
Other
0.013
0.018
0.004 0.006
0.016 2.5 ThO2
Wire Source *National Standard Co Drwer-Harns Co. $ Hoskms Manufacturing Co.
Table II. Parabolic Rate Constants for the Early Stage: k, (g/cm 2 )2/sec
N 155
DH 242
T~
k
Time, hr
760 871 982 1093 1149
7.59 X 10-is 1.13X 10"13 1.33 X 10-]2 9.08X 10"12 2.54 X 10"xx
30 8 50 >75 16
k 1.75 X 3.56X 3.41 X 2.04X
Hastelloy X Time, hr
10-14 10-23 10"12 10"lz
k
8 4 75 >100
in the oxide scales, they appear to have little or no effect on the oxidation rate. 1. F. W. Cole, J. B. Padden, and A. R. Spencer: Oxidation Resistant Materials for Transpiration-Cooled Gas Turbine Blades (11. Wire Specimen Tests), NASA CR1184, September, 1968. 2. P. Kofstad: High-Temperature Oxtdation of Metals, pp. 12, 18, John Wiley & Sons, Inc., New York, 1966.
Activity of Copper in Solid Cu-Au Alloys
1.12 X 2A2X 1.77 X 2.40X
TD NiCr
Time, hr 10"x4 10"13 10"12 10"H
k
~>100 >100 50 50
1.83X 5.07 X 2.27X 2.00 X
>100 50 4 8
the electrolyte surface by greatly increasing the diffusion path and hence reduces the drift in measured electromotive forces.
Table I. ActiviW Data in the Cu-Au System
Pct Cu
solid Cu-Au alloys as a part of a program to survey the thermodynamic properties of solid Cu-Au-Ag alloys. The measurements were made in an electromotive force cell of the type.
20
825
256 84 36 83 85 86.42
46.7
60
825 825 875 829 829 723 877
27.85 27.25 25.45 28.78
824 722 817 879
80
- 0.15 CaOICu + CuzOIPt The general configuration of the equipment was patterned after Rapp and Maak. I A modification that r e sulted in improved stability of the measured electromotive forces was the use of the electrolyte in the
85
f o r m of c y l i n d r i c a l c r u c i b l e (-} i n . d i a m b y 1 i n . length). The reference p e l l e t (Cu + C u ~ O ) w a s p r e s s e d against the outside and the alloy pellet against the in-
90
s i d e of t h e c r u c i b l e b a s e . T h i s p r o c e d u r e reduces the migration of metal through the gas phase and along
95
J. TRONDSEN and P. BOLSAITIS are Graduate Student and Associate Professor, respectively, Engineering Materials Program, Chemical Engineering Department, University of Maryland, College Park, Md. Manuscript submitted February 23, 1970.
98
Temp, ~
EMF, my
dE/dt, 825~176
DATAhas been obtained for the activity of copper in
2022-VOLUME 1,JULY 1970
10"14 10"13 10"z2 10"12
3. W. C. Hagel and A. U. Seybolt: J. Electrochem. Soc., 1961, vol. 108, p. 1146. 4. E. A. Gulbransen and K. F. Andrew: J. Electrochem. Soc., 1957, vol. 104, p. 334. 5. S. J. Grisaffe and C. E. Lowell: Examination of Oxide Scales on Heat Remtmg Alloys, NASA TN D-5019, February, 1969. 6. E. A. Gulbransen and K. F. Andrew: J. Electrochem. Soc., 1959, vol. 106, p. 941. 7. N. Blrks and H. Ricke
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