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230. Improved molecular still and sublimer for vacuum operation
76
Classified Abstracts
37 : 16 : 41 225. Determination of hydrogen and oxygen in metallic uranium. Japan. The behaviour of gases in metallic uranium is very important to the metallurgist, and accurate determinations of the The author was able to determine amount of gas are necessary. 0.2 - 0.4 p.p.m. of hydrogen in metallic uranium by extraction in vucuo for 20 min. at 900°C. Determination of oxygen was carried out by fusion extraction at 1850°C in a platinum bath. (in Japanese) (Author, modified) Y. Morimoto 163-166.
and A. Hirayama,
Japan Analyst, 11(2), Feb. 1962,
37 : 22 226. An application of micromanometer for gas determination in metals. S. Suzuki, Japan An&.$ 11 (3), March 1962, 356-358. 37 227. Gas chromatographic determination of gases in metals. Japan. The author used gas chromatography for the determination of gases in metals, and designed an apparatus whereby the gases extracted from metal specimens in the vacuum fusion furnace by a mercury diffusion pump were collected in a gas burette by an improved Toepler pump. The gases were then transferred to a gas chromatograph by means of a novel threeway cock. The analysis was carried out with a standard gas chromatograph by detection of thermal conductivity with molecular sieve 5A and argon elution. When one gram of metal specimen was supplied for analysis, the limits of determination for gas components were expressed in weight per cent as follows : 0.00002 hydrogen, 0.0009 nitrogen, and 0.0028 oxygen. The method and equipment used proved to be very efficient for determination of gases in metals by the conventional method. (in (Author, modified) Japanese) S. Suzuki, Japan Analyst, 11 (6), June 1962, 618-621. 37 : 41 : 53 228. Studies on sintered copper-chromium powder compacts. India. The mechanical and physical properties of copperchromium alloys containing up to 10 per cent of Cr, prepared by the powder metallurgy technique and sintered in vacuum were studied. The mixed metal powders were heated in a silica tube furnace at 900-1000°C and a oressure of the order of 0.2 torr. Subsequent compacting was d&e at a pressure of 24 ton/sq. in. in a hydraulic press. Addition of 2.5 per cent Cr to the powder compacts increases the tensile strength, hardness, density and elastic constants of the sintered product to that of fully annealed Larger additions of Cr E.T.P. (electrolytic tough pitch) copper. have no beneficial results and a 10 per cent addition causes a w. J. s. marked decrease in ductility of the product. A. M. Rao and A. A. Krishnan, J. Sci Indus. Rex, 21B (5), May 1962, 150. 37 : 53 229. Pumping systems for vacuum metallurgy. The main vacuum metallurgical processes Great Britain. currently in use are melting, heat treatment, brazing, welding and sintering. The general factors governing the choice of a vacuum pumping system are briefly considered. A diagram shows the steep rise in capital cost when pumping high gas loads with Experience has shown that most decreasing operating pressure. vacuum sintering and brazing processes are operated at pressures in the range lo-* to 1O-3 torr and are best pumped by a vapour diffusion pump/rotary mechanical pump combination. Annealing, on the other hand, covers a much wider range of pressures, from below 1O-3 torr for reactive metals (Ti, Zr, Ta, etc.) to 0.1 torr for bright annealing of copper. In the latter case, a rotary D. A .P. mechanical pump alone will usually suffice. M. E. Harper,
Vucniqrfe, 2 (5), Jan. 1962, 2-5.
225-234
37 : 28 : 41 Refining of CdSb and preparation of CdSb single crystals by zone melting. See Abstr. No. 186. 37 : 22 : 33 Drift tube-mass spectrometer for studies of low-energy ionmolecule reactions, See Abstr. No. 178. 31 : 45 : 42 Jointing graphite to graphite.
38.
Distillation,
See Abstr. No. 242.
Organic Chemistry, Analysis
Isotopic
Gas
38 : 14 : 20 230. Improved molecular still and sublimer for vacuum operation. U.S.A. The molecular still and sublimer were designed to meet the demand for low-cost equipment which could be easily assembled, dismantled and cleaned, and which would give effective sealing under high vacuum. Both apparatus use the principle of an open-end, jacketed, inverted cone for a condenser surface with the vacuum source at the apex of the cone. D.
R. J. McCarter,
A. P.
Rev. Sci. Instrum., 33 (3), March 1962, 388-389.
39.
Miscellaneous
Applications
39 231. Automatic gas-chromatographic sampling from static systems of sub-atmospheric pressure. Canada. An automatically operating gas chromatograph has been devised in order to follow a chemical reaction taking place between two gaseous components at sub-atmospheric pressure. The operation and design of the apparatus are described in detail and diagrams of the pneumatic and electrical circuits are given. The reliability of the unit is illustrated by the fact that it has operated for over 7000 hours, during which time the only maintenance required was the replacement of one open-closed D. A. P. toggle valve. K. Casey, et al., An&f, 87 (1039), Oct. 1962, 835-837. 39
232. First vacuum-type power circuit recloser developed by G. E. Anon, Insulation, 8 (2), Feb. 1962, 31. 39
233. The oxidation of sputtered tantalum films. U.S.A. The oxidation of sputtered tantalum films has been studied over a temperature range of lOO”-600°C in oxygen at a gas pressure of 7.6 cm of Hg. The results obtained by means of a vacuum microbalance are compared with data on bulk tantalum, and it is found the rate of oxidation and amount of oxidation is considerably smaller than the bulk. A logarithmic relation was found to represent the data best in the range 400”-600°C. The factors which may give rise to the differences found between the (Author) film and the bulk are discussed. H. Basseches,
J. Electrochem. SOL, 109, June 1962, 475-479.
39 234. Chemical vapor deposition of tungsten at low pressure. A. Miller and G. D. Barnett, J. Electrochem. Sot., 109, Oct. 1962, 973L976. 39 : 36 Huge new unit for drying transformer insulation has automatically controlled heat and vacuum. See Abstr. No. 220.
Classified Abstracts
37 : 16 : 41 225. Determination of hydrogen and oxygen in metallic uranium. Japan. The behaviour of gases in metallic uranium is very important to the metallurgist, and accurate determinations of the The author was able to determine amount of gas are necessary. 0.2 - 0.4 p.p.m. of hydrogen in metallic uranium by extraction in vucuo for 20 min. at 900°C. Determination of oxygen was carried out by fusion extraction at 1850°C in a platinum bath. (in Japanese) (Author, modified) Y. Morimoto 163-166.
and A. Hirayama,
Japan Analyst, 11(2), Feb. 1962,
37 : 22 226. An application of micromanometer for gas determination in metals. S. Suzuki, Japan An&.$ 11 (3), March 1962, 356-358. 37 227. Gas chromatographic determination of gases in metals. Japan. The author used gas chromatography for the determination of gases in metals, and designed an apparatus whereby the gases extracted from metal specimens in the vacuum fusion furnace by a mercury diffusion pump were collected in a gas burette by an improved Toepler pump. The gases were then transferred to a gas chromatograph by means of a novel threeway cock. The analysis was carried out with a standard gas chromatograph by detection of thermal conductivity with molecular sieve 5A and argon elution. When one gram of metal specimen was supplied for analysis, the limits of determination for gas components were expressed in weight per cent as follows : 0.00002 hydrogen, 0.0009 nitrogen, and 0.0028 oxygen. The method and equipment used proved to be very efficient for determination of gases in metals by the conventional method. (in (Author, modified) Japanese) S. Suzuki, Japan Analyst, 11 (6), June 1962, 618-621. 37 : 41 : 53 228. Studies on sintered copper-chromium powder compacts. India. The mechanical and physical properties of copperchromium alloys containing up to 10 per cent of Cr, prepared by the powder metallurgy technique and sintered in vacuum were studied. The mixed metal powders were heated in a silica tube furnace at 900-1000°C and a oressure of the order of 0.2 torr. Subsequent compacting was d&e at a pressure of 24 ton/sq. in. in a hydraulic press. Addition of 2.5 per cent Cr to the powder compacts increases the tensile strength, hardness, density and elastic constants of the sintered product to that of fully annealed Larger additions of Cr E.T.P. (electrolytic tough pitch) copper. have no beneficial results and a 10 per cent addition causes a w. J. s. marked decrease in ductility of the product. A. M. Rao and A. A. Krishnan, J. Sci Indus. Rex, 21B (5), May 1962, 150. 37 : 53 229. Pumping systems for vacuum metallurgy. The main vacuum metallurgical processes Great Britain. currently in use are melting, heat treatment, brazing, welding and sintering. The general factors governing the choice of a vacuum pumping system are briefly considered. A diagram shows the steep rise in capital cost when pumping high gas loads with Experience has shown that most decreasing operating pressure. vacuum sintering and brazing processes are operated at pressures in the range lo-* to 1O-3 torr and are best pumped by a vapour diffusion pump/rotary mechanical pump combination. Annealing, on the other hand, covers a much wider range of pressures, from below 1O-3 torr for reactive metals (Ti, Zr, Ta, etc.) to 0.1 torr for bright annealing of copper. In the latter case, a rotary D. A .P. mechanical pump alone will usually suffice. M. E. Harper,
Vucniqrfe, 2 (5), Jan. 1962, 2-5.
225-234
37 : 28 : 41 Refining of CdSb and preparation of CdSb single crystals by zone melting. See Abstr. No. 186. 37 : 22 : 33 Drift tube-mass spectrometer for studies of low-energy ionmolecule reactions, See Abstr. No. 178. 31 : 45 : 42 Jointing graphite to graphite.
38.
Distillation,
See Abstr. No. 242.
Organic Chemistry, Analysis
Isotopic
Gas
38 : 14 : 20 230. Improved molecular still and sublimer for vacuum operation. U.S.A. The molecular still and sublimer were designed to meet the demand for low-cost equipment which could be easily assembled, dismantled and cleaned, and which would give effective sealing under high vacuum. Both apparatus use the principle of an open-end, jacketed, inverted cone for a condenser surface with the vacuum source at the apex of the cone. D.
R. J. McCarter,
A. P.
Rev. Sci. Instrum., 33 (3), March 1962, 388-389.
39.
Miscellaneous
Applications
39 231. Automatic gas-chromatographic sampling from static systems of sub-atmospheric pressure. Canada. An automatically operating gas chromatograph has been devised in order to follow a chemical reaction taking place between two gaseous components at sub-atmospheric pressure. The operation and design of the apparatus are described in detail and diagrams of the pneumatic and electrical circuits are given. The reliability of the unit is illustrated by the fact that it has operated for over 7000 hours, during which time the only maintenance required was the replacement of one open-closed D. A. P. toggle valve. K. Casey, et al., An&f, 87 (1039), Oct. 1962, 835-837. 39
232. First vacuum-type power circuit recloser developed by G. E. Anon, Insulation, 8 (2), Feb. 1962, 31. 39
233. The oxidation of sputtered tantalum films. U.S.A. The oxidation of sputtered tantalum films has been studied over a temperature range of lOO”-600°C in oxygen at a gas pressure of 7.6 cm of Hg. The results obtained by means of a vacuum microbalance are compared with data on bulk tantalum, and it is found the rate of oxidation and amount of oxidation is considerably smaller than the bulk. A logarithmic relation was found to represent the data best in the range 400”-600°C. The factors which may give rise to the differences found between the (Author) film and the bulk are discussed. H. Basseches,
J. Electrochem. SOL, 109, June 1962, 475-479.
39 234. Chemical vapor deposition of tungsten at low pressure. A. Miller and G. D. Barnett, J. Electrochem. Sot., 109, Oct. 1962, 973L976. 39 : 36 Huge new unit for drying transformer insulation has automatically controlled heat and vacuum. See Abstr. No. 220.