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Reversible and irreversible changes in the work function and electrical conductivity of titanium dioxide in response to the chemisorption of oxygen
Classified
abstracts
234-213
exposure of tantalum to the gas phase and causes a decrease of the rate of hydrogen absorption. Although this process is probably responsible for the loss of activity there also appears to be a second effect contributing to the decrease of the permeation rate arising either from diffusion of palladium into tantalum or from diffusion of an impurity, eg inters’itially dissolved oxygen, from the bulk of the tantalum membrane to the tantalum-palladium interface. D Jewett and A C Makrides, Rep ITR-2; A D-650986, March 1967, 44 pages (Sci Tech Aerospare Reps, 5 (l7), 3014, N67-30359). I6 : IX 204. Influence of hydrogen on the electron emission of metals excited by 1 to 10 keV ions. (USSR) MO, Ta, Ni. Cu and stainless &eel foils were bombarded by H:, Hz
and H: ions with energies of I to IO keV in a hydrogen atmosphere with pressures of 5 x 10m6to 0.3 torr and the ion-electron emission coefficients were measured. For target temperatures of 300°K the measured value of the coefficient does not depend on hydrogen pressure for MO, Ta and Ni, but for Cu above IO--2torr and for stainless steel above 3 x IOe3 torr the coefficient is increasing. For the target temperatures of 1,200”K the coefficient is constant in the measured pressure range for MO and Ta, but is decreasing above 3 x IOe2 torr for Ni, above IO-* torr for stainless steel and above 9 x IO-* torr for Cu. This effect is connected with hydrogen chemisorption. A A Dorozhkin and N N Petrov, Z/I Tekh Fiz, 37 (9), Sept 1967, 1686-I 690 (in Rnssian). I6 : 21 205. Investigation
of helium
sorption
by films of condensed
gases.
208. Hydrogen oxidation high vacuum. (USSR)
I7 by nitrous oxide on platinum purified in ultra-
The catalytic oxidation of hydrogen by nitrous oxidc on a platinum surface was investigated for platinum cleaned by baking at 10 I0 torr and with gas purity measured by an omegatron. The reaction velocity was determined for different hydrogen/nitrous oxide n‘ixtures and pressures of IO-’ to IO-’ torr at temperatures of -- 30 to i 200’C. The measured values show agreement with the Langmuir-Hinshelwood theory. I I Tret’yakov et al. Dokl Akutl Nn~/k SSSR, 176 (3), 2lst Sept 1967, 64 l-644
(i/l Russian).
209. Stimulation of ZnS phosphors by the far infrared. Stimulation experiments with ZnS phosphors, using
I7 : 33 (Germany)
IR wavelengths from 2 to I5 I,, were performed at liquid helium temperatures. The construction of the cryostat is described, and the experimental results arc discussed. G Baur et al, P/r,, 206 (3). 1967, 229-246 (i/r Grrnlcr/r). 17
: 34
(Germany) Examples of space problems involving low temperature techniques are described. In this connection, special low temperature plants for space simulation purposes are included, which must meet typical conditions of vacuum and radiation. Prospective developments are briefly discussed. W Baldus, Rep DGRRI WGLR, Ott 1966, 7 paEes (it, Germs/r) (Sci
210. Low temperature
techniques and aeronautics.
Tech Aerospace
Reps, 5 (I 5), 2755, N67-28702).
18. GASEOUS
ELECTRONICS
(USSR)
Sorptidn of helium by films of hydrogen, nitrogen. argon and methane at temperatures of 2.34.2”K was investigated and best results were obtained with nitrogen. The measured heats of sorption at 4.2”K were 120 cal/mol for 0.4 per cent sorbed He in nitrogen and 95 cal/mol for 4 per cent He concentration. Steady helium pressures of lo-’ torr at 0.1 rer cent sorbed He concentration and 2.5 x IOm2torr for 4 per cent He were observed. At 0.5 per cent He in nitrogen, the sticking coefficient of helium is about 0.1 at 4.2”K. V B Yuferov et al, Z/z Tekh Fiz, 37 (9), Sept 1967, 1726-1728 (it1 Russiulr).
I8 : Ih Electron emission from tungsten under proton bombardment. nitrogen adsorption. See abstract number 200.
I8 : I6 Influence of hydrogen on the electron emission of metals excited by 1 to to 10 kV ions. See abstract number 204.
I8 : I6
I6 206. Nitrogen chemisorption
and the mechanism of iron purified in high vacuum. (USSR)
of ammonia synthesis
The sticking coefficient of N, on Fe was measured as 0.01 at 200°C and at nitrogen pressure of IO-’ torr. Investigations of the synthesis of ammonia from N, and H, on Fe thin films at 80 to 400°C and at IO-4 to IO-’ torr showed that the speed of reaction is higher for the case of synthesis from atomic nitrogen adsorbed on Fe surfaces than for molecular nitrogen. This synthesis is not limited by nitrogen chemisorption as the adsorption rate is much higher than the rate of synthesis. I 1 Tret’yakov et al, Dokl Akari Naltk SSSR, 175 (6), 2lst Aug 1967, 1332-l 335 (i/l Russian). I6 :
I8
207. Reversible
and irreversible changes in the work function and electrical conductivity of titanium dioxide in response to the chemisorption of oxygen. (USSR) Rutile with a surface of I5 m’/g was oxidized at 500°C in an oxygen
atmosphere and subsequently annealed at 10-O torr. The dependence of the work function, electrical conductivity and the oxygen chemisorption of samples at a temperature 20°C higher than the previous annealing temperature, was investigated. In the annealing temperature range of 20 to 200°C only irreversible changes were found, but in the range of 200 to 350°C the changes are partially reversible and this phenomenon is stronger at higher temperatures. A highest value of adsorbed oxygen of 4 x I 013 mol/cm2 was measured for an annealing temoerature of 200°C. E N Figurovskaya and V F Kiselev, Dokl Akad 21st Aug 1967, 1336-1339 (in Russian).
Nauk
SSSR,
17.5 (6),
17. THERMODYNAMICS
Research
on the enthalpy
abstract number 342. 96
of nitrogen-oxygen-argon
17:40 mixtures. See
Effect of
Reversible and irreversible changes in the work function and electrical conductivity of titanium dioxide in response to the chemisorption of oxygen. See abstract number 207.
I8 : 22 211. Corpuscular diagnostics of a hot plasma. (USSR) The review article deals with investigations of the energy output from the plasma, measurements of the total particle streams, electrostatic analysis of the ion and electron energies, mass analysis of the plasma ions and neutral atoms, analysis of nuclear reaction products, analysis of the stream of fast electrons from plasma, miscellaneous passive diagnostics (including high speed manometers), probe methoc!s Lising atomic beams and with plasma electric field investigations. I82 references are included. V V Afrosimov and I P Gladkovskiy, Z/7 Tekh Fiz, 37 (9), Sept 1X7. 1557-l 597 (in Rmim). IX 212. Investigation of the plasma of a He-Ne 6,328 A wavelength generation. (USSR)
laser in the region
of
Using the probe method, the electron distribution and temperature were measured in the positive column of a discharge in He-Ne mixtures at pressures of 0.35 to 1.4 torr. Discharge tube diameters of 3 to 15 mm were investigated for plasma generation in the wavelength region of 6,328 A. I M Belousova et al, Z/1 Tekh Fiz, 37 (9\, Sept 1967. 1681~~1685(ilr Rltssiu/?). I8 213. Cathode drop in vacuum arcs with thin film cathode. (USSR) The cathode drop was measured in vacuum arcs at 5 IO i torr with thin film cathodes obtained by sputtering the electrode material on the second electrode with subsequent voltage reversal. The cathode drop does not depend on the current and is lower by 3 to 5 eV than the bulk cathode values for Cu. Ag, Au, Be, Mg, Er, Al. Ti, Hf. Ta, Cr, MO, W. Te. Fe, Co, Ni and Pt. The values of Ca, Sr, 211, Cd, Sn and Bi are almost the qame for both thin film and bulk cathodes. V E Grakov, Zh Tekh Fiz, 37 (9). Sept 1967, 1704-1706 (in Russian).
abstracts
234-213
exposure of tantalum to the gas phase and causes a decrease of the rate of hydrogen absorption. Although this process is probably responsible for the loss of activity there also appears to be a second effect contributing to the decrease of the permeation rate arising either from diffusion of palladium into tantalum or from diffusion of an impurity, eg inters’itially dissolved oxygen, from the bulk of the tantalum membrane to the tantalum-palladium interface. D Jewett and A C Makrides, Rep ITR-2; A D-650986, March 1967, 44 pages (Sci Tech Aerospare Reps, 5 (l7), 3014, N67-30359). I6 : IX 204. Influence of hydrogen on the electron emission of metals excited by 1 to 10 keV ions. (USSR) MO, Ta, Ni. Cu and stainless &eel foils were bombarded by H:, Hz
and H: ions with energies of I to IO keV in a hydrogen atmosphere with pressures of 5 x 10m6to 0.3 torr and the ion-electron emission coefficients were measured. For target temperatures of 300°K the measured value of the coefficient does not depend on hydrogen pressure for MO, Ta and Ni, but for Cu above IO--2torr and for stainless steel above 3 x IOe3 torr the coefficient is increasing. For the target temperatures of 1,200”K the coefficient is constant in the measured pressure range for MO and Ta, but is decreasing above 3 x IOe2 torr for Ni, above IO-* torr for stainless steel and above 9 x IO-* torr for Cu. This effect is connected with hydrogen chemisorption. A A Dorozhkin and N N Petrov, Z/I Tekh Fiz, 37 (9), Sept 1967, 1686-I 690 (in Rnssian). I6 : 21 205. Investigation
of helium
sorption
by films of condensed
gases.
208. Hydrogen oxidation high vacuum. (USSR)
I7 by nitrous oxide on platinum purified in ultra-
The catalytic oxidation of hydrogen by nitrous oxidc on a platinum surface was investigated for platinum cleaned by baking at 10 I0 torr and with gas purity measured by an omegatron. The reaction velocity was determined for different hydrogen/nitrous oxide n‘ixtures and pressures of IO-’ to IO-’ torr at temperatures of -- 30 to i 200’C. The measured values show agreement with the Langmuir-Hinshelwood theory. I I Tret’yakov et al. Dokl Akutl Nn~/k SSSR, 176 (3), 2lst Sept 1967, 64 l-644
(i/l Russian).
209. Stimulation of ZnS phosphors by the far infrared. Stimulation experiments with ZnS phosphors, using
I7 : 33 (Germany)
IR wavelengths from 2 to I5 I,, were performed at liquid helium temperatures. The construction of the cryostat is described, and the experimental results arc discussed. G Baur et al, P/r,, 206 (3). 1967, 229-246 (i/r Grrnlcr/r). 17
: 34
(Germany) Examples of space problems involving low temperature techniques are described. In this connection, special low temperature plants for space simulation purposes are included, which must meet typical conditions of vacuum and radiation. Prospective developments are briefly discussed. W Baldus, Rep DGRRI WGLR, Ott 1966, 7 paEes (it, Germs/r) (Sci
210. Low temperature
techniques and aeronautics.
Tech Aerospace
Reps, 5 (I 5), 2755, N67-28702).
18. GASEOUS
ELECTRONICS
(USSR)
Sorptidn of helium by films of hydrogen, nitrogen. argon and methane at temperatures of 2.34.2”K was investigated and best results were obtained with nitrogen. The measured heats of sorption at 4.2”K were 120 cal/mol for 0.4 per cent sorbed He in nitrogen and 95 cal/mol for 4 per cent He concentration. Steady helium pressures of lo-’ torr at 0.1 rer cent sorbed He concentration and 2.5 x IOm2torr for 4 per cent He were observed. At 0.5 per cent He in nitrogen, the sticking coefficient of helium is about 0.1 at 4.2”K. V B Yuferov et al, Z/z Tekh Fiz, 37 (9), Sept 1967, 1726-1728 (it1 Russiulr).
I8 : Ih Electron emission from tungsten under proton bombardment. nitrogen adsorption. See abstract number 200.
I8 : I6 Influence of hydrogen on the electron emission of metals excited by 1 to to 10 kV ions. See abstract number 204.
I8 : I6
I6 206. Nitrogen chemisorption
and the mechanism of iron purified in high vacuum. (USSR)
of ammonia synthesis
The sticking coefficient of N, on Fe was measured as 0.01 at 200°C and at nitrogen pressure of IO-’ torr. Investigations of the synthesis of ammonia from N, and H, on Fe thin films at 80 to 400°C and at IO-4 to IO-’ torr showed that the speed of reaction is higher for the case of synthesis from atomic nitrogen adsorbed on Fe surfaces than for molecular nitrogen. This synthesis is not limited by nitrogen chemisorption as the adsorption rate is much higher than the rate of synthesis. I 1 Tret’yakov et al, Dokl Akari Naltk SSSR, 175 (6), 2lst Aug 1967, 1332-l 335 (i/l Russian). I6 :
I8
207. Reversible
and irreversible changes in the work function and electrical conductivity of titanium dioxide in response to the chemisorption of oxygen. (USSR) Rutile with a surface of I5 m’/g was oxidized at 500°C in an oxygen
atmosphere and subsequently annealed at 10-O torr. The dependence of the work function, electrical conductivity and the oxygen chemisorption of samples at a temperature 20°C higher than the previous annealing temperature, was investigated. In the annealing temperature range of 20 to 200°C only irreversible changes were found, but in the range of 200 to 350°C the changes are partially reversible and this phenomenon is stronger at higher temperatures. A highest value of adsorbed oxygen of 4 x I 013 mol/cm2 was measured for an annealing temoerature of 200°C. E N Figurovskaya and V F Kiselev, Dokl Akad 21st Aug 1967, 1336-1339 (in Russian).
Nauk
SSSR,
17.5 (6),
17. THERMODYNAMICS
Research
on the enthalpy
abstract number 342. 96
of nitrogen-oxygen-argon
17:40 mixtures. See
Effect of
Reversible and irreversible changes in the work function and electrical conductivity of titanium dioxide in response to the chemisorption of oxygen. See abstract number 207.
I8 : 22 211. Corpuscular diagnostics of a hot plasma. (USSR) The review article deals with investigations of the energy output from the plasma, measurements of the total particle streams, electrostatic analysis of the ion and electron energies, mass analysis of the plasma ions and neutral atoms, analysis of nuclear reaction products, analysis of the stream of fast electrons from plasma, miscellaneous passive diagnostics (including high speed manometers), probe methoc!s Lising atomic beams and with plasma electric field investigations. I82 references are included. V V Afrosimov and I P Gladkovskiy, Z/7 Tekh Fiz, 37 (9), Sept 1X7. 1557-l 597 (in Rmim). IX 212. Investigation of the plasma of a He-Ne 6,328 A wavelength generation. (USSR)
laser in the region
of
Using the probe method, the electron distribution and temperature were measured in the positive column of a discharge in He-Ne mixtures at pressures of 0.35 to 1.4 torr. Discharge tube diameters of 3 to 15 mm were investigated for plasma generation in the wavelength region of 6,328 A. I M Belousova et al, Z/1 Tekh Fiz, 37 (9\, Sept 1967. 1681~~1685(ilr Rltssiu/?). I8 213. Cathode drop in vacuum arcs with thin film cathode. (USSR) The cathode drop was measured in vacuum arcs at 5 IO i torr with thin film cathodes obtained by sputtering the electrode material on the second electrode with subsequent voltage reversal. The cathode drop does not depend on the current and is lower by 3 to 5 eV than the bulk cathode values for Cu. Ag, Au, Be, Mg, Er, Al. Ti, Hf. Ta, Cr, MO, W. Te. Fe, Co, Ni and Pt. The values of Ca, Sr, 211, Cd, Sn and Bi are almost the qame for both thin film and bulk cathodes. V E Grakov, Zh Tekh Fiz, 37 (9). Sept 1967, 1704-1706 (in Russian).