It is shown that bimetal strips which use palladium—silver alloys as the active component are sensitive detectors of gaseous hydrogen. Concentrations of hydrogen in STP nitrogen as low as 50 ppm have been detected with this technique. Fast response times are obtained at bimetal strip operating temperatures of 200–300°C. The experimentally observed steady state behavior of these strips is in good agreement with theory.

Topics
Sensors, Transition metals, Chemical elements
1.
T.
Tsuchida
,
J. Phys. Soc. Japan
18
,
1016
(
1963
).
Crossref
Search ADS
 
2.
G.
Rosenhall
,
Ann. Physik
24
,
297
(
1935
).
3.
E.
Wicke
 and
G.
Bohmholdt
,
Z. Physik. Chem. N.F.
42
,
115
(
1964
).
Crossref
Search ADS
 
4.
L. R.
Rubin
,
Engelhard Industries Tech. Bull.
7
,
55
(
1966
).
5.
H.
Brodowsky
 and
E.
Poeschel
,
Z. Physik. Chem. N.F.
44
,
143
(
1965
).
Crossref
Search ADS
 
6.
F. J. Norton, U.S. Patent No. 2,307,800, January 12, 1943.
7.
S.
Timoshenko
,
J. Opt. Soc. Amer.
11
,
233
(
1925
).
Crossref
Search ADS
 
8.
R. M.
Sears
,
Mater. Res. Stand.
3
,
981
(
1963
).
9.
T.
Tsuchida
,
J. Phys. Soc. Japan
18
,
1016
(
1963
).
Crossref
Search ADS
 
10.
H.
Brodowsky
,
Z. Physik. Chem. N.F.
44
,
129
(
1965
).
Crossref
Search ADS
 
11.
H.
Brodowsky
 and
E.
Wicke
,
Engelhard Industries Tech. Bull.
7
,
41
(
1966
).
12.
O. Kubaschewski and E. Evans, Metallurgical Thermochemistry (Pergamon Press, Inc., New York, 1965), 3rd ed., p. 44.
13.
While its corrosion resistance is not high, iron offers a reasonably good thermal expansion match to Pd and 75‐25 wt% Pd‐Ag and is readily available. 75‐25 wt% Pd‐Ag is also readily available—being widely used as a permeation membrane for hydrogen purification.
14.
Matheson Co., Inc., East Rutherford, N.J.
15.
W. H. Kohl, Materials and Techniques for Electron Tubes (Rein‐hold Publishing Corp., New York, 1960), p. 178.
16.
Ref. 15, p. 243.
17.
H. Albert, Engelhard Industries (private communication).
18.
Handbook of the Physicochemical Properties of the Elements, G. Samsonov, Ed. (IFI—Plenum, New York, 1968), p. 389.
19.
Internal stress levels can be estimated by the results presented in Ref. 7.
20.
Unfortunately, experimentally determined values for D with n<0.02 are not available. The quoted value for D was observed in the concentration range, 0.34<n<0.40 in 75‐25 wt% Pd‐Ag. As is now generally recognized, the use of this value at very low hydrogen concentrations may be inaccurate.
21.
J. Crank, The Mathematics of Diffusion (Oxford University Press, London, 1956), p. 43.
22.
B. I. Boltaks, Diffusion in Semiconductors (Academic Press Inc., New York, 1963), p. 111.
23.
The Corrosion Handbook, H. H. Uhlig, Ed. (John Wiley & Sons, Inc., New York, 1948), p. 304.
24.
U. U. Savolainen, Theory and Properties of Thermostat Metals and Engineering Laminates (John Wiley & Sons, Inc., New York, 1949).
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© 1969 The American Institute of Physics.
1969
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