634. Electron microscopic investigation of pyramidal structure formed on the surface of electro-deposited nickel

634. Electron microscopic investigation of pyramidal structure formed on the surface of electro-deposited nickel

Classified Abstracts 623-634 248 623. Simple technique for examination 30 : 33 of sputtering patterns. (U.S.A.) R. E. Nielsen and W. B. Shepherd, ...

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Classified Abstracts 623-634

248 623. Simple technique for examination

30 : 33 of sputtering patterns.

(U.S.A.)

R. E. Nielsen and W. B. Shepherd, Rev. Sci. Znstrum., 35 (l), Jan. 1964, 123-124. 624. Method for vacuum deposition of high purity oxides. J. L. Nicholson, Rev. Sci. Znstrum., 34 (8), Aug. 3,936.

30 (U.S.A.)

Measurement of the vapour density in a vacuum arc. No. 561.

33 : 17 See Abstr.

33 : 30 Critical magnetic fields of superconducting niobium films. See Abstr. No. 609. 33 : 30 The dynamic behaviour of magnetic thin films. See Abstr. No. 611.

30

33 : 30 Simple technique for examination of sputtering patterns. See Abstr. No. 623.

30 : 33 626. Simple electron bombardment apparatus for evaporating boron. (U.S.A.) K. L. Erdman et al., Rev. Sci. Zndrum., 35 (l), Jan. 1964,122-123.

33 : 30 Simple electron bombardment apparatus for evaporating boron. See Abstr. No. 626.

High vacuum coating device. (Great Britain) Anon., Engineering, 216 (5619), Oct. 1963, 566.

625.

33

30 : 41 627. Variable evaporation rate of tantalum. (U.S.S.R.) The evaporation of Tantalum in vacua from a laminated source containing Ta 182 was studied by the labelled atom method. The source was heated by an a.c. current and its temperature measured by means of an optical pyrometer, allowance being made for the emissivity of the metal. Special precautions were taken to ensure a uniform temperature distribution. The first series of experiments were carried out at the temperature range 1500-1900”K, the pressure being usually of the order of 5 x lo-’ torr and never exceeding 5 x 1O-6 torr. Over this range, the rate of evaporation varied exponentially with temperature, the the activation energy of the process being 99 kcal/mol. The rate of evaporation does not vary with the duration of heating and the The second series of experimental results are reproducible. experiments covered the range 2000”-2800°K. The results were now no longer reproducible, but depended on the time of heating. The authors attribute the change to the evaporation of surface impurities containing tantalum, and quote figures of the heat of sublimation of compounds of this type in support of this theory. (U.S.S.R.)

L. M.

(Bibliography

7 items).

V. A. Shustrov et al., Izvestia

Akademii

Nauk.,

Uzbekskoy

SSR,

1964 (I), 31-34.

31.

Evacuation and Sealing

31 : 19 The light emitting diode : Its application to a short path television link. See Abstr. No. 568. 628.

Slow

wave

dielectric

circuits in travelling-wave

(U.S.A.) C. H. Durrey and R. W. Grow, Trans. Z.E.E.E.,

31 tubes.

11 (l), Jan. 1964,

38. 31 629. Implosion danger overcome by new T.V. tube. Anon., Elec. Weekly, (179), 5 Feb, 1964,8. 31 630. High resolution cathode ray tube. (Great Britain) Anon., The Engineer, 217 (5634), 17 Jan. 1964, 143.

631. Development in vacuum spectrography.

Practical experiments conducted by means of the vacuum spectrograph analysis of steel and by the use of the capacitive unidirectional discharge have shown that the type of the counter electrode and of its impurity are of little importance. The opposite of this is found with carbon analysis. For the spectrometric analysis of non-homogeneous samples, the average is calculated of the results obtained by moving the test sample during the exposure. The author discusses the sparking curves of test pieces. (Italy) (Author) S. Echkard,

MetaNurgia

Ztaliana, 55, 1963, 405.

R. Redstone and M. C. Rowland, 1964,1115-1116.

Nature,

201 (4924), March

33 633. A new high-resolution dark-field electron microscope technique (Great

Britain)

It is now generally recognized

that high resolution dark field microscopy is essential for a comprehensive study of imperfections in crystalline materials. Commerical electron microscopes have however in the past not been designed with this technique in mind and consequently dark field work has been carried out to date only to a limited extent. The authors described modifications which they have applied to a commercial EM6 electron microscope so that it can be used with equal facility for dark and light field work. The electron beam in the instrument can now be tilted in any direction to the normal by f 4” and the standard specimen holder rotated through any angle about an axis parallel to that of the microscope. (Great Britain) W. J. S. 201 (4920), (15) Feb. 1964,

General Physics and Electronics

33 : 30 The dynamics of the domain structure of thin ferrite films in relation to temperature and magnetic field. See Abstr. No. 608.

(In Italian)

33 632. High temperature hydrogen isotope targets. (Great Britain) Hydrogen isotope targets in current use consist of zirconium or titanium films which have been impregnated with deuterium or tritium. The maximum temperature to which these targets can be raised is determined by the dissociation pressure of the hydride and is of the order of 300°C. This sets an uvver limit to the current density of the bombarding ions and hence to the neturon output which may be obtained in long periods of operation. The authors have investigated the possible use of rare earth metal deuterides and tritides for targets, i.e., the replacement of zirconium or titanium by neodymium or praesodymium. These targets can be heated in vacuum to at least 500°C without loss of de;terium or tritium. (Great Britain) W. J. S.

K. F. Hale and D. McLean, Nature, 696.

33.

(Italy)

33 634. Electron microscopic investigation

: 52

of pyramidal structure formed on the surface of electro-deposited nickel. (Great Britain) It seems probable that high mobility of dislocation on a growing

Classified Abstracts cathode surface is necessary to account for the development of pyramidal structure. Such high mobility could be a consequence of the exothermic character of the electro-deposition process and the fact that newly formed surfaces tend to a configuration which reduces their internal stresses. (Great Britain) w. J. s. B. C. Banerjee 1964, 602-603.

and P. L. Walker,

635-648

249

34 643. How altitude effects forced air cooling requirements of electronic equipment. (U.S.A.) G. G. Gebert, Adv. Electron. Circuit Packaging, 3, (1963), 168-180.

Nature, 201 (4919), 8 Feb.

36.

33 635. Testing of high-duty carbided cathodes under vacuum. (rr.S.S.R.) S. I. Zilitinkevich and M. D. Gurevich, Priborostroyeniye, 5 (5), 1962, 3-5. 33 636. Electron gun design. K. E. Groves, Des. Electron., 1 (l), Oct. 1963, 18. 33 : 45 637. Electron beam welding. R. Gobel, Tech. Digest, 5 (9), Sept. 1963,7. 33 638. Grid characteristics in vacuum tubes fitted with oxide cathodes. (U.S.S.R.) Y. V. Mokvichev and P. V. Poshekhenov, Radiotekhnika, 5 (4), 1962, 519-520. 33 :45 639. Vacuum and non vacuum techniques for electron beam welding. (Great Britain) Anon., Machinery, 103 (2665), 11 Dec. 1963, 1328.

Drying, Degassing

and Concentration

36 : 40 644. Installation for the degassing of liquids and solutions. (U.S.S.R.) The article describes an installation for purifying liquids from paramagnetic oxygen dissolved in them. The degassing method used was “ freezing, evacuation, thawing “. The preliminary evacuation cycle to 2.1O-2 torr was carried out with a fore pump. The reduction to 1O-4 torr was monitored with a vacuum meter VT-2 in conjunction with an LT-2 transducer, and in the range of 1O-3 to 1O-6 torr an ionization manometer VI-3 with a VI-3 transducer were used. Cooling traps were inserted for the protection of the transducers of the vacuum meters and of the working fluid of the high-vacuum pump from contamination with the vapours coming off the samples under test. A basic diagram of the installation is attached. (Bibliography 8 items). (U.S.S.R.) L. M. F. M. Samigullin, and A. Sh. Agashev, Pribory i Teckh. Eksper., 1,1964, 224-225.

37.

Metallurgy,

Inorganic Chemistry, Chemistry

Analytica! 37 : 28

Continuous zone-refining apparatus.

34.

High Altitude and Space Technology

34 : 16 Adhesive behaviour of silicate powders in V.H. vacuum. See Abstr. No. 559. Emphasis on space cryogenics advances at Linde. 560.

34 : 17 See Abstr. No.

34 640. Friction and wear of diamond in high vacuum. (Great Britain) The authors’ experiments indicate that when diamond surfaces slide on one another in a high vacuum (or the order of lo-i0 torr), adsorbed surface films are removed and the naked crystal surfaces exposed. Under these conditions, the coefficient of sliding friction approaches unity against a value of 0.05 in air at atmospheric pressure. It is shown that arrival of a fraction only of a monolayer of gas on the surface suffices to produce a marked reduction in the coefficient and the dependence of friction on orientation of the crystal provides additional evidence of the may have extreme thinness of the film. These observations practical relevance to the operation of mechanisms intended to operate in outer space. Under these conditions “jewel bearings ” may show unforeseen high friction and wear. (Great W. J. S. Britain) F. B. Bowden and A. E. Hanwell, Nature, 201 (4926), March 28, 1964, 1279-1281. 34 641. Vacuum problems in the simulation of very high altitudes. D. J. Crawley, Sot. Environ. Engnrs., ll[ 1963, 15. 34 642. Device for creep tests at high temperatures in vacuum or an inert medium. (U.S.A.) (Trans. from the Russian). V. G. Govorkov et al., Zndustr. Lab., 29 (3), Oct. 1963, 375-377.

See Abstr. No. 606.

37 645. Some considerations on the results of the determination of hydrogen content in steel. (ZtaZy) The advantages and consequences deriving from the adoption of the hot vacuum extraction method at 600°C for the determination of the hydrogen content in steels are discussed. The number of data, obtained from such a method of gas analysis, has permitted a statistical investigation on the influence of hydrogen content before degassing on the post-degassing content ; on the influence of air moisture on the hydrogen content in steels and on the dependence of flakes from the hydrogen content. Some consideration is finally given to the methods adopted to avoid (Authors) flake formation in steels. (ZtaZy) G. Timo and U. Lodi, (In Italian).

Metallurgia

Ztaliana, 55, (1963), 560. 37

646. Vacuum exploded melt makes super pure metals. Anon., Engineering News, (136), 27 Feb. 1964, 10.

(U.S.A.)

37 647. The effect of vacuum degassing of cast iron melted under atmospheric conditions. (Germany) J. Thienne, Giesserei, 50 (20). 1963,602-609. 37 648. Hydrogen peroxide in the slow thermal reaction of hydrogen and oxygen. (Great Britain) The experiments were carried out at pressures between 300 and 400 torr at a temperature of 538°C in a vessel coated with boric acid. The authors conclude that hydrogen peroxide is not an essential active species in the hydrogen/oxygen reaction, but is formed by a heterogeneous process which is distinct from the (Great main overall reaction in which water is produced. w. J. s. Britain) M. Green and J. W. Linnett, Nature, 202 (4927), 4 April 1964, 80.