- Email: [email protected]
1032. Electron attachment and detachment. II. Mixtures of O2 and CO2 and of O2 and H2O
Classified abstracts 1032-1042 the various metastable ions at 70 eV were determined. One parent-ion metastable transition was studied carefully : the methane loss at m/e 17.8 in C3 H8 and at m/e -- 19.7 in C3 Ds. This transition shows a pronounced isotope effect on the yield. Appearance potentials were determined for the ions involved by the RPD method and for the metastables themselves by conventional techniques. Details of the experimental apparatus are given. C Lifshitz and M Shapiro, J Chem Phys, 45 (11), I st Dec 1966, 4242-4248. 40 1032. Electron attachment and detachment. 11. Mixtures of 02 and COz and of Oz and H 2 0 . (USA) Electron-attachment coefficients in O2-CO2 and O2-H20 mixtures and electron-attachment-detachment equilibrium constants for 02 COz mixtures are obtained from drift-tube measurements. Some aspects of the apparatus are discussed but more detail can be obtained from previous publications which are referenced. The three-body attachment coefficients involving 02 and CO~ are 3.1 × 10 -a°, 4.0× 10 -30 and 2.7 × 10 -30 cm 6 sec at 300, 477, and 525°K. The electronnegative-ion equilibrium constant data are discussed in terms of possible mechanisms. J L Pack and A V Phelps, J Chem Phys, 45 (11), 1st Dec 1966, 4316-4329. 40 1033. Collision-induced dissociation of D2 ~ ions by argon and nitrogen. (USA) The reactions Dz+÷X---~ D + - - D ÷ X , where X is Ar or N~, were studied with an angular ion-scattering apparatus at ion energies in the range 5-120 eV. Kinetic-energy distributions as well as angular distributions of the D ÷ ions were determined. The apparatus, including vacuum system, is described in considerable detail. The method consists of directing a well-collimated, mass-analyzed, and energy-selected ion beam into a scattering region and analyzing the product ions with a 127 ° electrostatic velocity selector and an rf mass filter. The results are discussed in terms of a simple two-step collision model. R L Champion ct al, J Chem Phys, 45 (12), 15th Dec 1966, 4377-4384. 40 1034. Nondissociative electron capture in complex molecules and negative ion lifetimes. (USA) The formation and decay of parent negative ions were studied with electron-swarm and electron-beam techniques. The rate of attachment at thermal energies under electron-swarm conditions for SF~ and C~ He NO2 was determined to be 1.24× 109 and 2.1 × 107 sec 1 torr 1, respectively. Auto-ionization lifetimes for SF6 , Ca H5 NO2 , and (C H3 CO) 2 are reported to be 25, 40, and 12 ~t sec. respectively. A simple theor~ti :al treatment of long-lived negative ions is presented, and the possibility of estimating electron affinities from measurements of attachment cross sections and negative-ion lifetimes is pointed out. R N Compton et al, J Chem Phys, 45 (12), 15th Dec 1966, 4634-4639. 40 1035. Gaseous diffusion: the systems He-Kr, Ar-Kr and Kr-Xe. (USA) Gaseous diffusion coefficients are reported for the system He-Kr, A r - K r and Kr-Xe. The results were obtained over the temperature range 0 ° to 120°C with an apparatus of the Ney-Armistead type. Expressions describing the results are given. The experimental data compare favourably with results derived from viscosity measurements, but show deviations for thermal-conductivity-derived values. A P Malinauskas, J Chem Phys, 45 (12), 15th Dee 1966, 4704-4709.
45. SOLDERING, WELDING, BRAZING S O L D E R S 45 : 30 1036. Microwelding of vacuum deposited thin films. (France) General methods of producing connector bonds in vacuum deposited thin film circuits are reviewed and the requirements for quality are enumerated. The operation and construction of the Eyelet thermocompression bonder is described. This device incorporates a special tool which induces lateral flow of metal during bond formation, coupled with high precision of movement. The rate of approach and dwell time of the tool may be automatically controlled. A major advantage of the device is the ability to produce aluminium to aluminium welds. G V Planer, Le Vide, 21 (126), Nov-Dec 1966, 473-476 (in French)
304
45 1037. Vacuum brazing--from aluminium alloys up through the refractory metals. (USA) Superalloy and refractory type metals are discussed. These are typical examples of materials which, at the time they were developed, challenged the potentials and capabilities of existing joining processes and methods and led to the development of new joining techniques. The control of critical oxide contamination in joining has led to the use of vacuum processing as a means of affording protection from contamination. M M Schwarz, Metals Eng Quarterly, 6, 1966, 47 51. 45 1038. Selection of brazing alloys. (USA) A survey is given of the suitability of the more important industrial brazing alloys. Data are presented in tabular form relating to torch brazing, induction brazing, furnace brazing and vacuum brazing. M H Sloboda, Weld, Metal Fabr, 34, 1966, 386-393. 45 1039. Vacuum welding procedure. (Great Britain) Low carbon and slightly deoxidised steels and alloys may be welded by this method. The metal working parts are heated to their melting temperature by an electron beam and other metals such as Ti, Zr, AI and the rare earths are used as filler materials/deoxidants. These latter materials are vacuum degassed before use to remove any oxygen and so are able to take up the oxygen from the metal working parts. Balzers Patent-und-Lizenz Anstalt, Brit Patent, 1,053,567, Patent Abstr, 7 (5) part 7, 26th Jan 1967, 1.
46. GLASS BLOWING, G L A S S - T O - M E T A L AND CERAMICT O - M E T A L SEALING T E C H N I Q U E S 46 1040. Beryllium oxide-metal seals and their application to semiconductors. (France) Sintered beryllium oxide combines the mechanical strength and dielectric strength of ceramic oxides with excellent refractory properties and, most important, a very high thermal conductivity. It replaces alumina where improved thermal conductivity is required. To minimize thermal contact resistance and to ensure a tight joint, the beryllium oxide must be first metallized and then soldered or brazed to the metallic part. These joints have already found application in the manufacture of leak proof electron tubes, cooled delay lines and other devices. Their properties also recommend them for application to semiconductor devices such as transistor bases and power diode packages. A Dub~e, Le Vide, 21 (126), Nov-Dec 1966, 433-436 (in French). 46 1041. Metal-ceramic joints. (Germany) Metal components are joined to rod-form ceramic pieces by silvercopper soldering, after burning-in powdered high melting point metal on to the ceramic surface. So as to enhance thermal shock resistance when the metal and ceramic have different expansion coefficients, the high melting point powdered metal is burnt-in at a low temperature, such that the burnt-in coat is directly available for wetting the ceramic. (Author) Telefunken Patentverwertungs GmbH, German Patent 1,231,608, Patent Abstr, 7 (5) part C, 2nd Feb 1967, 10.
47. O U T G A S S I N G DATA, V A P O U R P R E S S U R E DATA, GETTERING DATA, RESIDUAL GASES IN V A C U U M SYSTEMS, RESIDUAL GAS ANALYSIS 47 : 37 Vapour pressure of different metals in the pressure range of 50-4000 torr. See abstract number 998. 47 1042. The surface potential of semiconductors in ultrahigh vacuum and controlled atmosphere. (France) The Kelvin vibrating condenser and static condenser methods were applied to determine the change of semiconductor surface potential caused by different atmospheric compositions. Germanium, silicon and gallium antimonide samples with an exposed surface area of about 1 cm 2 were chemically cleaned and placed in a vacuum bell-jar at about 10-9 torr. Changes in surface potential due to desorption were recorded and then various gases were introduced. The results for
45. SOLDERING, WELDING, BRAZING S O L D E R S 45 : 30 1036. Microwelding of vacuum deposited thin films. (France) General methods of producing connector bonds in vacuum deposited thin film circuits are reviewed and the requirements for quality are enumerated. The operation and construction of the Eyelet thermocompression bonder is described. This device incorporates a special tool which induces lateral flow of metal during bond formation, coupled with high precision of movement. The rate of approach and dwell time of the tool may be automatically controlled. A major advantage of the device is the ability to produce aluminium to aluminium welds. G V Planer, Le Vide, 21 (126), Nov-Dec 1966, 473-476 (in French)
304
45 1037. Vacuum brazing--from aluminium alloys up through the refractory metals. (USA) Superalloy and refractory type metals are discussed. These are typical examples of materials which, at the time they were developed, challenged the potentials and capabilities of existing joining processes and methods and led to the development of new joining techniques. The control of critical oxide contamination in joining has led to the use of vacuum processing as a means of affording protection from contamination. M M Schwarz, Metals Eng Quarterly, 6, 1966, 47 51. 45 1038. Selection of brazing alloys. (USA) A survey is given of the suitability of the more important industrial brazing alloys. Data are presented in tabular form relating to torch brazing, induction brazing, furnace brazing and vacuum brazing. M H Sloboda, Weld, Metal Fabr, 34, 1966, 386-393. 45 1039. Vacuum welding procedure. (Great Britain) Low carbon and slightly deoxidised steels and alloys may be welded by this method. The metal working parts are heated to their melting temperature by an electron beam and other metals such as Ti, Zr, AI and the rare earths are used as filler materials/deoxidants. These latter materials are vacuum degassed before use to remove any oxygen and so are able to take up the oxygen from the metal working parts. Balzers Patent-und-Lizenz Anstalt, Brit Patent, 1,053,567, Patent Abstr, 7 (5) part 7, 26th Jan 1967, 1.
46. GLASS BLOWING, G L A S S - T O - M E T A L AND CERAMICT O - M E T A L SEALING T E C H N I Q U E S 46 1040. Beryllium oxide-metal seals and their application to semiconductors. (France) Sintered beryllium oxide combines the mechanical strength and dielectric strength of ceramic oxides with excellent refractory properties and, most important, a very high thermal conductivity. It replaces alumina where improved thermal conductivity is required. To minimize thermal contact resistance and to ensure a tight joint, the beryllium oxide must be first metallized and then soldered or brazed to the metallic part. These joints have already found application in the manufacture of leak proof electron tubes, cooled delay lines and other devices. Their properties also recommend them for application to semiconductor devices such as transistor bases and power diode packages. A Dub~e, Le Vide, 21 (126), Nov-Dec 1966, 433-436 (in French). 46 1041. Metal-ceramic joints. (Germany) Metal components are joined to rod-form ceramic pieces by silvercopper soldering, after burning-in powdered high melting point metal on to the ceramic surface. So as to enhance thermal shock resistance when the metal and ceramic have different expansion coefficients, the high melting point powdered metal is burnt-in at a low temperature, such that the burnt-in coat is directly available for wetting the ceramic. (Author) Telefunken Patentverwertungs GmbH, German Patent 1,231,608, Patent Abstr, 7 (5) part C, 2nd Feb 1967, 10.
47. O U T G A S S I N G DATA, V A P O U R P R E S S U R E DATA, GETTERING DATA, RESIDUAL GASES IN V A C U U M SYSTEMS, RESIDUAL GAS ANALYSIS 47 : 37 Vapour pressure of different metals in the pressure range of 50-4000 torr. See abstract number 998. 47 1042. The surface potential of semiconductors in ultrahigh vacuum and controlled atmosphere. (France) The Kelvin vibrating condenser and static condenser methods were applied to determine the change of semiconductor surface potential caused by different atmospheric compositions. Germanium, silicon and gallium antimonide samples with an exposed surface area of about 1 cm 2 were chemically cleaned and placed in a vacuum bell-jar at about 10-9 torr. Changes in surface potential due to desorption were recorded and then various gases were introduced. The results for