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The lattice spacings of palladium-nickel-copper ternary alloys
70
JOURNALOFTHELESS-COMMONMETALS
Short Communications The lattice
spacings of palladium-nickel-copper
ternary
alloys
Both nickel and copper have face-centered cubic structures at all temperatures and from the atomic diameter comparison factor are expected to form a complete series of solid solutions. The existence of complete solubilityl with the possibility of clustering293 at low temperatures have been reported. Furthermore, nickel and palladium are reported to form a complete series of solid solution+. The third constituent binary
system,
palladium-copper,
exhibits
order-disorder
transformations
at
compositions ranging from (I) about IO at. o/0to somewhat above 25 at. y/opalladium corresponding to PdCu3 composition and (2) 30 at. 9/oto about 55 at. o/opalladium corresponding to Pd-Cu composition 1. It would be logical, therefore, to expect that palladium, nickel, and copper would be completely soluble in one another at room temperature with possible existence of order-disorder transitions at ternary compositions corresponding to low nickel contents and palladium around 50 at. o/oand 25 at. o/o(the rest copper).
compositions
ranging
For experimental evidence of deviation from random solid solutions, a study of the X-ray powder patterns of several ternary alloys of these elements was undertaken. In addition, since no data exist on the lattice spacing values of the ternary alloys, this investigation provides such values for the alloys studied. Experimental procedure Requisite amounts of spectroscopically pure copper and nickel powders obtained from Johnson & Mathey Co. and 99.999:/o pure palladium powder from W. C. Heraues & Co., West Germany, were mixed well and then compressed into pellets weighing about 2 g. The pellets were arc melted under purified argon atmosphere. The buttons were then given a homogenizing treatment in vacuum for fourteen days at about 900°C. For X-ray examination, filed powders of -240 mesh size were used. The initial filings in all cases were rejected. The powders were vacuum sealed in quartz capillary tubes, annealed for short periods at 650°C to remove stress, and furnace cooled to room temperature. All X-ray photographs were taken at room temperature (24’C) with filtered copper K radiation employing a 19 cm unicam camera. The exposure time for each run was about 5 h. Duplicate runs on the alloys were made to insure reproducibility. The diffraction lines on the films were measured with a vernier reading to 0.05 mm. An average of six readings was taken to determine a line position. Lattice parameter values, calculated for a number of diffraction lines, were plotted against the standard Nelson-Riley function to obtain an extrapolated value for each specimen at room temperature. In obtaining the extrapolated value the best fit straight line is drawn, giving very heavy weight to the high angle points. Chemical analysis on buttons left after filing was carried out to determine the quantities of the elements in the alloys. Both gravimetric and volumetric methods were used, and the accuracy of the analysis is believed to be about +0.5~/~. Only J. Less-Common
Metals,
9 (1965)70~73
SHORT COMMUNICATIONS TABLE LATTICE
Sample A-0.
I PARAMETER
VALUES
Composition cu 8.5 18.72
3 4 5
28.45 48.5 58.52
(1
78.8 18.2 28.6 41.2 50.2
: 9 IO II 12 13 I4 15
OF PALLADIUM-NICKEL-COPPER
of the
58.5 20.14 20.8 29.8
ALLOYS
Lattice
alloy (at.%)
Ni
2
I
71
Pd
9.87 11.1 II. 10.7 10.6
81.53 70. 60.5 40.8 3’.
3.791’ 3.7330 3.7046
10.85 20.8 20.4
IO.4 61.
3.6430 3.7810
51. 38.82
3.7596 3.7234 3.6924
19% 20.8
29.
21.
20.5
27.4 29.8
52.5 49.5 40.02 30.8
3.6632 3.7620 3.7510 3.7200 3 6908
30.05 30.2
I6
48.1
29.1
17 18
58.4 20.7 29.8 28.6
31. 39.6 39.5 44.6
22.8 10.7
3 655s 3 6120
39.h 30.7 26.75
3 7146 3 6850 3 6691
28.75 LO.2 29.8
50.8
20.5
59.8 59.7 69.8
19.9 IO.45 20.3 10.25
3 6468 3 6300 3 6000 3.6272
21 22 ‘3 24 25 20
27 28
19 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
9.9 19.8 Y24.r 5.20 8.74 9.18 9.79 11.65 13.23 17.88 18.52 21.41 23.86 27.71 32.87 34.48 38.10 43.69 55.42 65.54 60.50 70.27 74.17 61.16 51.58 31.94 100.0 -
70. 17.5 79.44 69.79 62.38 51.62 38.5 15.90 74.73 28.91 40.37 15.71 64.53 27. 15.78 55.34 24.61 13.03 11.19 32.18 22.36 12.30 23.31 33.72 il.97
58.3 14.86 21.47 28.44 38.59 49.5 70.87 7.39 52.57 38.22 60.97 7.76 40. 49.74 6.56
3 5786 3-7798 3.5989 3.6270 3 6598 3 6962 3.7436 3.8132 3.5706 3.6685 3.7072 3.7854 3.5791 3.7196 3.7529 3.5839
31.7” 31.55 23.37 7.32 7.37
3.6155
13.53 15.54 14.7” 13.09
3.6475 3.6373 3.6269 3.6068
100.0 100.0
value
3.8454 3.8160
38.1
19 LO
parameter
(J)
3.6945 3.6976 3.6706 3.6041
3.6151 3.5240 3.8906 ~~______ J. Less-Common
Metals. 9
(1965)
70-7
SHORT COMMUNICATIONS
72
two alloys with small and large copper contents, numbered 24 and 43 respectively, were spectroscopically analysed for oxygen contents. The oxygen contents were 20 p.p.m. and 65 p.p.m. respectively. The rest of the alloys were assumed to contain oxygen within the values represented for the above two alloys. All the compositions atom per cent.
in this paper,
unless otherwise
indicated,
are given in
Results and discussion The composition of the alloys and their lattice parameter values are given in Table I and shown in Fig. I on the triangular graph. Also included in Table I are the lattice parameter values of the pure metals. The lattice parameter values given represent the average of two readings. Differences in the duplicate values varied from a minimum of O.OOOI A to a maximum of 0.0007 A-the maximum being obtained only for three alloys. For most of the alloys, however, differences of the order of 0.0003~0.0004 A, in their duplicate values, were obtained. Considering the experimental deviations for both lattice spacing calculations and chemical
analysis,
most of the alloys show only small deviations
from the values
CU
Pd
3.645
3615
Fig. 1. Lattice parameter us. composition J. Less-Common
Metals,
9 (1965) 70-73
370
376
(Pd-Ni-Cu
3.74
372
alloys).
3700
3.66
366
36.64 362
SHORT COMMUiYICATIOXS
73
one would expect for these compositions if the linear relationship shown by the straight lines is expected to hold. (Equal lattice parameter points of the binaries are connected with straight lines as shown in the figure.) There is, however, an area in the diagram, as shown in the figure, that shows strong negative deviations from the above mentioned &o-parameter lines. In addition, alloys with compositions (a) 39. 6 lo Cu, 40 O;, Xi, 20.35 (ju Pd and (b) 38. 4 t: Cu, 10. S9 ‘!ANi, 50. S O” ,
Received
February
rzth,
1965
JOURNALOFTHELESS-COMMONMETALS
Short Communications The lattice
spacings of palladium-nickel-copper
ternary
alloys
Both nickel and copper have face-centered cubic structures at all temperatures and from the atomic diameter comparison factor are expected to form a complete series of solid solutions. The existence of complete solubilityl with the possibility of clustering293 at low temperatures have been reported. Furthermore, nickel and palladium are reported to form a complete series of solid solution+. The third constituent binary
system,
palladium-copper,
exhibits
order-disorder
transformations
at
compositions ranging from (I) about IO at. o/0to somewhat above 25 at. y/opalladium corresponding to PdCu3 composition and (2) 30 at. 9/oto about 55 at. o/opalladium corresponding to Pd-Cu composition 1. It would be logical, therefore, to expect that palladium, nickel, and copper would be completely soluble in one another at room temperature with possible existence of order-disorder transitions at ternary compositions corresponding to low nickel contents and palladium around 50 at. o/oand 25 at. o/o(the rest copper).
compositions
ranging
For experimental evidence of deviation from random solid solutions, a study of the X-ray powder patterns of several ternary alloys of these elements was undertaken. In addition, since no data exist on the lattice spacing values of the ternary alloys, this investigation provides such values for the alloys studied. Experimental procedure Requisite amounts of spectroscopically pure copper and nickel powders obtained from Johnson & Mathey Co. and 99.999:/o pure palladium powder from W. C. Heraues & Co., West Germany, were mixed well and then compressed into pellets weighing about 2 g. The pellets were arc melted under purified argon atmosphere. The buttons were then given a homogenizing treatment in vacuum for fourteen days at about 900°C. For X-ray examination, filed powders of -240 mesh size were used. The initial filings in all cases were rejected. The powders were vacuum sealed in quartz capillary tubes, annealed for short periods at 650°C to remove stress, and furnace cooled to room temperature. All X-ray photographs were taken at room temperature (24’C) with filtered copper K radiation employing a 19 cm unicam camera. The exposure time for each run was about 5 h. Duplicate runs on the alloys were made to insure reproducibility. The diffraction lines on the films were measured with a vernier reading to 0.05 mm. An average of six readings was taken to determine a line position. Lattice parameter values, calculated for a number of diffraction lines, were plotted against the standard Nelson-Riley function to obtain an extrapolated value for each specimen at room temperature. In obtaining the extrapolated value the best fit straight line is drawn, giving very heavy weight to the high angle points. Chemical analysis on buttons left after filing was carried out to determine the quantities of the elements in the alloys. Both gravimetric and volumetric methods were used, and the accuracy of the analysis is believed to be about +0.5~/~. Only J. Less-Common
Metals,
9 (1965)70~73
SHORT COMMUNICATIONS TABLE LATTICE
Sample A-0.
I PARAMETER
VALUES
Composition cu 8.5 18.72
3 4 5
28.45 48.5 58.52
(1
78.8 18.2 28.6 41.2 50.2
: 9 IO II 12 13 I4 15
OF PALLADIUM-NICKEL-COPPER
of the
58.5 20.14 20.8 29.8
ALLOYS
Lattice
alloy (at.%)
Ni
2
I
71
Pd
9.87 11.1 II. 10.7 10.6
81.53 70. 60.5 40.8 3’.
3.791’ 3.7330 3.7046
10.85 20.8 20.4
IO.4 61.
3.6430 3.7810
51. 38.82
3.7596 3.7234 3.6924
19% 20.8
29.
21.
20.5
27.4 29.8
52.5 49.5 40.02 30.8
3.6632 3.7620 3.7510 3.7200 3 6908
30.05 30.2
I6
48.1
29.1
17 18
58.4 20.7 29.8 28.6
31. 39.6 39.5 44.6
22.8 10.7
3 655s 3 6120
39.h 30.7 26.75
3 7146 3 6850 3 6691
28.75 LO.2 29.8
50.8
20.5
59.8 59.7 69.8
19.9 IO.45 20.3 10.25
3 6468 3 6300 3 6000 3.6272
21 22 ‘3 24 25 20
27 28
19 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
9.9 19.8 Y24.r 5.20 8.74 9.18 9.79 11.65 13.23 17.88 18.52 21.41 23.86 27.71 32.87 34.48 38.10 43.69 55.42 65.54 60.50 70.27 74.17 61.16 51.58 31.94 100.0 -
70. 17.5 79.44 69.79 62.38 51.62 38.5 15.90 74.73 28.91 40.37 15.71 64.53 27. 15.78 55.34 24.61 13.03 11.19 32.18 22.36 12.30 23.31 33.72 il.97
58.3 14.86 21.47 28.44 38.59 49.5 70.87 7.39 52.57 38.22 60.97 7.76 40. 49.74 6.56
3 5786 3-7798 3.5989 3.6270 3 6598 3 6962 3.7436 3.8132 3.5706 3.6685 3.7072 3.7854 3.5791 3.7196 3.7529 3.5839
31.7” 31.55 23.37 7.32 7.37
3.6155
13.53 15.54 14.7” 13.09
3.6475 3.6373 3.6269 3.6068
100.0 100.0
value
3.8454 3.8160
38.1
19 LO
parameter
(J)
3.6945 3.6976 3.6706 3.6041
3.6151 3.5240 3.8906 ~~______ J. Less-Common
Metals. 9
(1965)
70-7
SHORT COMMUNICATIONS
72
two alloys with small and large copper contents, numbered 24 and 43 respectively, were spectroscopically analysed for oxygen contents. The oxygen contents were 20 p.p.m. and 65 p.p.m. respectively. The rest of the alloys were assumed to contain oxygen within the values represented for the above two alloys. All the compositions atom per cent.
in this paper,
unless otherwise
indicated,
are given in
Results and discussion The composition of the alloys and their lattice parameter values are given in Table I and shown in Fig. I on the triangular graph. Also included in Table I are the lattice parameter values of the pure metals. The lattice parameter values given represent the average of two readings. Differences in the duplicate values varied from a minimum of O.OOOI A to a maximum of 0.0007 A-the maximum being obtained only for three alloys. For most of the alloys, however, differences of the order of 0.0003~0.0004 A, in their duplicate values, were obtained. Considering the experimental deviations for both lattice spacing calculations and chemical
analysis,
most of the alloys show only small deviations
from the values
CU
Pd
3.645
3615
Fig. 1. Lattice parameter us. composition J. Less-Common
Metals,
9 (1965) 70-73
370
376
(Pd-Ni-Cu
3.74
372
alloys).
3700
3.66
366
36.64 362
SHORT COMMUiYICATIOXS
73
one would expect for these compositions if the linear relationship shown by the straight lines is expected to hold. (Equal lattice parameter points of the binaries are connected with straight lines as shown in the figure.) There is, however, an area in the diagram, as shown in the figure, that shows strong negative deviations from the above mentioned &o-parameter lines. In addition, alloys with compositions (a) 39. 6 lo Cu, 40 O;, Xi, 20.35 (ju Pd and (b) 38. 4 t: Cu, 10. S9 ‘!ANi, 50. S O” ,
Received
February
rzth,
1965