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1511. Microelectronics and materials in the vacuum environment of space
Classified
abstracts
1500-1512 .
1500. Surfaces of solids in vacua.
,J
(Switzerlund)
The surface reactions of solids under high vacuum are discussed as well as special techniques for the preparation of clean surfaces such as bombardment by noble gas ions or crystal formation in vacua. The investigation of surface structure by field ion-emission spectroscopy and electron microscopy is described and some results for films of germanium, tungsten, nickel, ahuninium and nickel oxide are presented. W Epprecht, Schweizer Arch Angew Wissensch Tech, 31 (2), Feb 1965,
33-39,
(in German).
33 : 39 1501. Method of preparing cellular grids for electrovacuum equipment. (USSR)
A new method of preparing cellular (honeycomb) grids for electrovacuum equipment is described. The main distinguishing feature of this is that the grid is formed directly in the diauhraam or resonator concerned by eiectro-erosion; this improves thd quaiity of the grids and is more favourable from a productivity point of view. The methods of setting up the machining electrodes are described and optimum conditions for obtaining a good finish are indicated. I I Sazhin, Author’s Certificate, USSR, CIass 49, 1101 (B 23 p), No 173116,
claimed
2713162, published
3117165, (in Russian). 33
: 31
Investigation of recrystallization of vacuum-deposited Nb$n iu the high temperature microscope. (Germany) Recrystallization and grain growth of NbsSn was studied in the high temperature microscope. M Hoffman and R Maier, Prak MetaIIographie, 2 (I), 1965, 31-34, 1502.
(in German).
34. High
altitude
and
space
technology 34
: 27
Vacuum leak detection of large space environmental chambers. See abstract number 1332. 34 : 39 1503. Adhesion and fatigue properties of materials in vacuum. (USA) Investigations dealing with the pressure dependence of fatigue in aluminium indicate that, in the absence of air, fatigue life improves two- to five-fold, depending on the applied stress level. Doubling the cycling frequency from 25 to 50 cps produces negligible change in fatigue life. Fatigue crack formation appears to be relatively insensitive to pressure level. Multiple cracks are observed in samples fatigued in air and 1 x 10es torr, but only a single fracture is observed at 2 x lo-’ torr. Fatigue resistance in vacuum increases steadily as fatigue stress decreases from about 13500 to 8500 psi. It was found that adhesion force increases with abrasion time in studies of oxides films. Low strength ductile material such as annealed aluminium and copper exhibit substantial self-adhesion after cleaning. The sensitivity of solid adhesion welding to the plastic flow criterion is graphed and shows that the softer more ductile materials adhere more than do the harder alloys when a constant stress is applied. M J Hordon and L R Allen, 6th Annual Symposium on Space Environment Simulation, Center, Tenn).
May
1965
(Arnold
Engineering
Development
34 : 47 1504. Intluence of product contaminants on vacuum and flight system performance. (USA)
The effect of cleaning on vacuum system performance reveals that vacuum system base pressure at 1000°F can be reduced from 5.10e5 torr to 2.10-’ torr. Cleaning of the motor and the chamber load results in reducing the pump load by a factor of 330 to one; size, cost, and reliability of the vacuum pumping system are found to improve after careful decontamination. A discussion of environmental effects on creep properties of structural materials is included. S Giles, 6th Annual Symposium on Space Environmental Simulation (Arnold
Engineering
Development
Center,
Term), May
1966,
54-61. 34
A large ultrahigh-vacuum environmental chamber with liquid helium cooled walls. (USA) A description is given of a large UHV environmental chamber for simulating space conditions. In order to duplicate the temperature of the space sink, the test object is surrounded by a cryogenic wall at liquid helium temperature. A schematic of the vacuum system is shown, and is basically triple walled. The outer chamber is a conventional vacuum vessel and the inner chamber is cooled to liquid nitrogen temperatures. Four 35 in and one 20 in diffusion pumps are used, and He refrigeration/liquefier supplied the cold helium to the cryowall. C D Elderkin and J M Bradford, NASA, Langley Res Center, 1965. 1506.
34 1507. Prediction of cryopumping speeds in space simulation chambers.
(USA) An experimental programme to determine the effects of gas and cryosurface temperature on the cryopumping speeds of gases to be removed from environmental test chambers is discussed. Pumping speeds determined by the pressure drop method and capture coefficients for CO, COB, nitrogen, Ar, Oa, Ne, air and a 90 per cent Na - 10 per cent 0, mixture are presented. J P Dawson, J Spacecraft Rockets, 3 (2), 1966, 218-223. 34 1508. The Institute for Space Simulation in Porz-Wahn,West Germany. (Germany)
The facilities are described. The simulation chambers currently in use there - some for vacuum only, some for vacuum and cold, and two also containing high intensity xenon lamps for solar radiation simulation - are de&r&d. P Kleber, DVL-Nachrichten, Ott 1965, 124-127, (in German). 34 1509. Scaling of transient temperature distributions of simple bodies in a space chamber. (USA)
Thermal sealing of bodies with cycled internal heat sources was investigated in a cold high vacuum environment. Modelling relations were derived and test carried out in two configurations. The first array of bodies consisted of a flat plate, sphere and cylinder arranged in a close network but not in physical contact with each other. The second system consisted of two spheres connected by a cylindrical rod. The experimental transient temperature distributions in the models were in agreement with the scaling relations. D L Adkins, AEDC-TR-65-177, AD-471212, Ott 1965 (AR0 Inc Arnold
Air Station,
Tenn).
34 1510. Vacuum testing of spaceflight systems. (Germany) Detailed description of the vacuum simulation facility constructed near Munich for testing the third stage of the Eldo rocket. The main chamber is 4 m in diam and 7 m high; it has a working pressure of 1O-B torr which can be maintained during full-power testing of the rocket engine. H Giihre, Wissenschaftliche Gessellschaft fur Luft und Ramnfahrt, 1965, (in German). 34 1511. Microelectronics and materials in the vacuum environment of space. (USA)
This bibliography consists of 204 refs and is directed toward the specific aspects of space environment hard vacuum and radiation as these environments affect microelectronics. V J Mungle, Autonetics, Anaheim, Calih 1965, 118 pages. 34
1965. 34
1505. Adhesion of metals in the space environment. (USA) Studies have been made of the parameters of time, pressure, and temperature that influence adhesion of structural metals in vacuum. The objective was IO provide spacecraft designers with engineering data to ensure separation of instrument capsules and other components from spacecraft in the space environment. These studies were conducted at an environmental pressure of 5 x 10-O torr over a tempera-
468
ture range of 25°C to 500°C and at compressive stresses within the elastic limits of the materials. Data are presented showing the extent of adhesion of a wide variety of materials under these conditions. P M Winslow and D V McIntyre, J Vuc Sci Tech, 3 (2), MarlApr
High speed power amplifier using an electron switched p-n junction. (USA) A bare contoured junction does not hold up under a combination of vacuum and temperature above 9o”C, in the test chamber. Planar junction diodes were made which withstood such a combination at a temperature of 150°C for a period in excess of 1000 hours. N E Ake, Tung-Sol Elextric Znc, Livingstone, New Jersey, 1965, 1512.
21 pages.
abstracts
1500-1512 .
1500. Surfaces of solids in vacua.
,J
(Switzerlund)
The surface reactions of solids under high vacuum are discussed as well as special techniques for the preparation of clean surfaces such as bombardment by noble gas ions or crystal formation in vacua. The investigation of surface structure by field ion-emission spectroscopy and electron microscopy is described and some results for films of germanium, tungsten, nickel, ahuninium and nickel oxide are presented. W Epprecht, Schweizer Arch Angew Wissensch Tech, 31 (2), Feb 1965,
33-39,
(in German).
33 : 39 1501. Method of preparing cellular grids for electrovacuum equipment. (USSR)
A new method of preparing cellular (honeycomb) grids for electrovacuum equipment is described. The main distinguishing feature of this is that the grid is formed directly in the diauhraam or resonator concerned by eiectro-erosion; this improves thd quaiity of the grids and is more favourable from a productivity point of view. The methods of setting up the machining electrodes are described and optimum conditions for obtaining a good finish are indicated. I I Sazhin, Author’s Certificate, USSR, CIass 49, 1101 (B 23 p), No 173116,
claimed
2713162, published
3117165, (in Russian). 33
: 31
Investigation of recrystallization of vacuum-deposited Nb$n iu the high temperature microscope. (Germany) Recrystallization and grain growth of NbsSn was studied in the high temperature microscope. M Hoffman and R Maier, Prak MetaIIographie, 2 (I), 1965, 31-34, 1502.
(in German).
34. High
altitude
and
space
technology 34
: 27
Vacuum leak detection of large space environmental chambers. See abstract number 1332. 34 : 39 1503. Adhesion and fatigue properties of materials in vacuum. (USA) Investigations dealing with the pressure dependence of fatigue in aluminium indicate that, in the absence of air, fatigue life improves two- to five-fold, depending on the applied stress level. Doubling the cycling frequency from 25 to 50 cps produces negligible change in fatigue life. Fatigue crack formation appears to be relatively insensitive to pressure level. Multiple cracks are observed in samples fatigued in air and 1 x 10es torr, but only a single fracture is observed at 2 x lo-’ torr. Fatigue resistance in vacuum increases steadily as fatigue stress decreases from about 13500 to 8500 psi. It was found that adhesion force increases with abrasion time in studies of oxides films. Low strength ductile material such as annealed aluminium and copper exhibit substantial self-adhesion after cleaning. The sensitivity of solid adhesion welding to the plastic flow criterion is graphed and shows that the softer more ductile materials adhere more than do the harder alloys when a constant stress is applied. M J Hordon and L R Allen, 6th Annual Symposium on Space Environment Simulation, Center, Tenn).
May
1965
(Arnold
Engineering
Development
34 : 47 1504. Intluence of product contaminants on vacuum and flight system performance. (USA)
The effect of cleaning on vacuum system performance reveals that vacuum system base pressure at 1000°F can be reduced from 5.10e5 torr to 2.10-’ torr. Cleaning of the motor and the chamber load results in reducing the pump load by a factor of 330 to one; size, cost, and reliability of the vacuum pumping system are found to improve after careful decontamination. A discussion of environmental effects on creep properties of structural materials is included. S Giles, 6th Annual Symposium on Space Environmental Simulation (Arnold
Engineering
Development
Center,
Term), May
1966,
54-61. 34
A large ultrahigh-vacuum environmental chamber with liquid helium cooled walls. (USA) A description is given of a large UHV environmental chamber for simulating space conditions. In order to duplicate the temperature of the space sink, the test object is surrounded by a cryogenic wall at liquid helium temperature. A schematic of the vacuum system is shown, and is basically triple walled. The outer chamber is a conventional vacuum vessel and the inner chamber is cooled to liquid nitrogen temperatures. Four 35 in and one 20 in diffusion pumps are used, and He refrigeration/liquefier supplied the cold helium to the cryowall. C D Elderkin and J M Bradford, NASA, Langley Res Center, 1965. 1506.
34 1507. Prediction of cryopumping speeds in space simulation chambers.
(USA) An experimental programme to determine the effects of gas and cryosurface temperature on the cryopumping speeds of gases to be removed from environmental test chambers is discussed. Pumping speeds determined by the pressure drop method and capture coefficients for CO, COB, nitrogen, Ar, Oa, Ne, air and a 90 per cent Na - 10 per cent 0, mixture are presented. J P Dawson, J Spacecraft Rockets, 3 (2), 1966, 218-223. 34 1508. The Institute for Space Simulation in Porz-Wahn,West Germany. (Germany)
The facilities are described. The simulation chambers currently in use there - some for vacuum only, some for vacuum and cold, and two also containing high intensity xenon lamps for solar radiation simulation - are de&r&d. P Kleber, DVL-Nachrichten, Ott 1965, 124-127, (in German). 34 1509. Scaling of transient temperature distributions of simple bodies in a space chamber. (USA)
Thermal sealing of bodies with cycled internal heat sources was investigated in a cold high vacuum environment. Modelling relations were derived and test carried out in two configurations. The first array of bodies consisted of a flat plate, sphere and cylinder arranged in a close network but not in physical contact with each other. The second system consisted of two spheres connected by a cylindrical rod. The experimental transient temperature distributions in the models were in agreement with the scaling relations. D L Adkins, AEDC-TR-65-177, AD-471212, Ott 1965 (AR0 Inc Arnold
Air Station,
Tenn).
34 1510. Vacuum testing of spaceflight systems. (Germany) Detailed description of the vacuum simulation facility constructed near Munich for testing the third stage of the Eldo rocket. The main chamber is 4 m in diam and 7 m high; it has a working pressure of 1O-B torr which can be maintained during full-power testing of the rocket engine. H Giihre, Wissenschaftliche Gessellschaft fur Luft und Ramnfahrt, 1965, (in German). 34 1511. Microelectronics and materials in the vacuum environment of space. (USA)
This bibliography consists of 204 refs and is directed toward the specific aspects of space environment hard vacuum and radiation as these environments affect microelectronics. V J Mungle, Autonetics, Anaheim, Calih 1965, 118 pages. 34
1965. 34
1505. Adhesion of metals in the space environment. (USA) Studies have been made of the parameters of time, pressure, and temperature that influence adhesion of structural metals in vacuum. The objective was IO provide spacecraft designers with engineering data to ensure separation of instrument capsules and other components from spacecraft in the space environment. These studies were conducted at an environmental pressure of 5 x 10-O torr over a tempera-
468
ture range of 25°C to 500°C and at compressive stresses within the elastic limits of the materials. Data are presented showing the extent of adhesion of a wide variety of materials under these conditions. P M Winslow and D V McIntyre, J Vuc Sci Tech, 3 (2), MarlApr
High speed power amplifier using an electron switched p-n junction. (USA) A bare contoured junction does not hold up under a combination of vacuum and temperature above 9o”C, in the test chamber. Planar junction diodes were made which withstood such a combination at a temperature of 150°C for a period in excess of 1000 hours. N E Ake, Tung-Sol Elextric Znc, Livingstone, New Jersey, 1965, 1512.
21 pages.