A spectrographic method for the analysis of zirconium-hafnium mixtures covering the hafnium/zirconium concentration ratio range from 0.001 to 100 is described. The samples are excited as conducting pellets prepared from mixtures of the combined oxides with powdered flake graphite. An overdamped condenser discharge is used for excitation. By utilizing a series of internal standard line pairs, the complete concentration range can be covered by a single exposure. At the same time, photographic photometry errors can be reduced by restricting the intensity ratio range over which these line pairs are measured. The unique similarity in the physical and chemical properties of zirconium and hafnium, combined with the use of line pairs of similar excitation characteristics, provides a system in which ideal internal standard conditions can be achieved. Experimental results indicate that, within the wide limits investigated, variations in excitation conditions, extraneous elements, graphite-oxide ratio in the pellets, crystal structure of the oxides, and chemical form of the samples, have no apparent effect on the analytical results. Precision determinations showed a standard deviation of about 1.5 to 2.0 percent.
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G. R. Harrison (Editor) M.I.T. Wave-Length Tables (John Wiley and Sons, Inc., New York, 1939).
C. C. Kiess and H. K. Kiess, Bur. Stand. J. Research 6, 621 (1931).
C. C. Kiess and H. K. Kiess, Bur. Stand. J. Research 5, 1205 (1930).
W. Finkelnburg, Zeits. f. Naturforschung 2a, 16 (1947). Personal communication from Dr. W. F. Meggers indicated that Finkelnburg’s value for the ionization potential of hafnium is now considered to be high, and that Finkelnburg recently gave an estimate of 5.9 ± 0.4 ev. This is the value used in computing the excitation potential for the hafnium lines in Table I.
W. F. Meggers and B. F. Scribner, J. Research Nat. Bur. Stand. 13, 625 (1934).
Table II
Operating conditions for the analysis of zirconium-hafnium mixtures.
Spectrograph
Jarrell-Ash 21-ft. stigmatic grating spectrograph with optical system previously describeda
Upper electrode (positive)
Graphite rod,
in. diameter and 1 in. long, pointed at one end
Lower electrode (negative)
Cylindrical pellet prepared as described in the text held in a special pellet holder
Analytical gap
4 mm
Excitation source
An overdamped 60-cycle d.c. discharge with arc-like characteristics obtained from ARL multisource with the following settings:b
Capacitance:
14 μf
Inductance:
480 μh
Resistance:
65 ohms
Phase angle:
30 degrees
Exposure time
40 sec.
Slit
0.05 mm
Emulsion
Spectrum analysis No. 1 (Eastman)
Wave-length region
2300 to 3500A, first order
Sector
Eight-step sector (speed adjusted to prevent synchronization with source)
Iron arc, two-step sector, preliminary curve methodd
See reference 1.
M. F. Hasler and H. W. Dietert, J. Opt. Soc. Am. 33, 218 (1943).
H. W. Dietert and J. Schuch, J. Opt. Soc. Am. 31, 54 (1941).
See reference 29.
Table III
Effect of oxide-graphite ratio on analytical intensity ratios.
Graphite/oxide
2:1
0.437
0.229
1.18
0.595
4:1
0.426
0.225
1.17
0.590
6:1
0.423
0.222
1.16
0.595
Table IV
Effect of excitation of various compounds on analytical results.
Compound
ZrO2
1.75
0.50
1.07
Zr(P2O7)2
1.73
0.50
0.98
ZrOCl2
1.72
0.56
1.04
ZrO(NO3)2
1.68
0.51
0.98
ZrOSO4
1.62
0.51
0.99
Zr(SeO3)2
1.74
0.50
0.99
Table V
Effect of crystal form on analytical intensity ratios.
Temperature of ignition
125°C
1.18
0.412
0.227
700°C
1.19
0.415
0.226
1100°C
1.16
0.409
0.226
Table VI
Precision of hafnium-zirconium determinations.
Sample No.
No. of determinations on individual plates
Percent hafnium
Line pair
Percent standard deviation
1
50
1.20
1.40
2
12
13.8
1.26
3
12
37.5
1.68
4
12
50.0
1.96
5
12
69.2
1.35
6
12
85.1
1.95
7
12
95.4
0.87
3
12
37.5
5.05
Table VII
Comparison of spectrographic and chemical atomic weight determinations.
Percent hafnium
Sample
Spectrographic
Atomic weight
A
9.54±0.2
9.18±0.3
B
13.3 ±0.3
14.72±0.3
E
35.0 ±0.5
36.93±0.2
H
50.0 ±0.6
50.56±0.2
I
63.0 ±0.7
64.79±0.2
J
71.9 ±0.8
72.52±0.3
Table VIII
Comparison of analytical results on standard samples prepared at the New Brunswick Laboratory of the AEC.
G. R. Harrison (Editor) M.I.T. Wave-Length Tables (John Wiley and Sons, Inc., New York, 1939).
C. C. Kiess and H. K. Kiess, Bur. Stand. J. Research 6, 621 (1931).
C. C. Kiess and H. K. Kiess, Bur. Stand. J. Research 5, 1205 (1930).
W. Finkelnburg, Zeits. f. Naturforschung 2a, 16 (1947). Personal communication from Dr. W. F. Meggers indicated that Finkelnburg’s value for the ionization potential of hafnium is now considered to be high, and that Finkelnburg recently gave an estimate of 5.9 ± 0.4 ev. This is the value used in computing the excitation potential for the hafnium lines in Table I.
W. F. Meggers and B. F. Scribner, J. Research Nat. Bur. Stand. 13, 625 (1934).
Table II
Operating conditions for the analysis of zirconium-hafnium mixtures.
Spectrograph
Jarrell-Ash 21-ft. stigmatic grating spectrograph with optical system previously describeda
Upper electrode (positive)
Graphite rod,
in. diameter and 1 in. long, pointed at one end
Lower electrode (negative)
Cylindrical pellet prepared as described in the text held in a special pellet holder
Analytical gap
4 mm
Excitation source
An overdamped 60-cycle d.c. discharge with arc-like characteristics obtained from ARL multisource with the following settings:b
Capacitance:
14 μf
Inductance:
480 μh
Resistance:
65 ohms
Phase angle:
30 degrees
Exposure time
40 sec.
Slit
0.05 mm
Emulsion
Spectrum analysis No. 1 (Eastman)
Wave-length region
2300 to 3500A, first order
Sector
Eight-step sector (speed adjusted to prevent synchronization with source)
Iron arc, two-step sector, preliminary curve methodd
See reference 1.
M. F. Hasler and H. W. Dietert, J. Opt. Soc. Am. 33, 218 (1943).
H. W. Dietert and J. Schuch, J. Opt. Soc. Am. 31, 54 (1941).
See reference 29.
Table III
Effect of oxide-graphite ratio on analytical intensity ratios.
Graphite/oxide
2:1
0.437
0.229
1.18
0.595
4:1
0.426
0.225
1.17
0.590
6:1
0.423
0.222
1.16
0.595
Table IV
Effect of excitation of various compounds on analytical results.
Compound
ZrO2
1.75
0.50
1.07
Zr(P2O7)2
1.73
0.50
0.98
ZrOCl2
1.72
0.56
1.04
ZrO(NO3)2
1.68
0.51
0.98
ZrOSO4
1.62
0.51
0.99
Zr(SeO3)2
1.74
0.50
0.99
Table V
Effect of crystal form on analytical intensity ratios.
Temperature of ignition
125°C
1.18
0.412
0.227
700°C
1.19
0.415
0.226
1100°C
1.16
0.409
0.226
Table VI
Precision of hafnium-zirconium determinations.
Sample No.
No. of determinations on individual plates
Percent hafnium
Line pair
Percent standard deviation
1
50
1.20
1.40
2
12
13.8
1.26
3
12
37.5
1.68
4
12
50.0
1.96
5
12
69.2
1.35
6
12
85.1
1.95
7
12
95.4
0.87
3
12
37.5
5.05
Table VII
Comparison of spectrographic and chemical atomic weight determinations.
Percent hafnium
Sample
Spectrographic
Atomic weight
A
9.54±0.2
9.18±0.3
B
13.3 ±0.3
14.72±0.3
E
35.0 ±0.5
36.93±0.2
H
50.0 ±0.6
50.56±0.2
I
63.0 ±0.7
64.79±0.2
J
71.9 ±0.8
72.52±0.3
Table VIII
Comparison of analytical results on standard samples prepared at the New Brunswick Laboratory of the AEC.