AMERICAN VACUUM SOCIETY CLASSICS

HANDBOOK OF MATERIALS

AND TECHNIQUES FOR VACUUM

DEVICES

Walter H. Kohl

AIP

American Institute of Physics New York

CONTENTS

Preface v 1. Glass 1

The nature of glassThe composition of glassGas permeation through glassThe mechan-ical strength of glassChemical strengthening of glassThe annealing of glassStress analy-sis Volume conductivityElectrolysis in glassSurface conductivityDielectric properties Glass in radiation fieldsSpecial Processes and Applications: ManipulationCutting and polishing of small holesThin glass windowsGlass sheet and filmsGlass shrinking Cleaning of glassParticulate contaminationOutgassingPowdered glassSolder glass

2. Ceramics 61 Raw materials and body compositions (conventional electrical porcelain, low-loss steatite, forsterite, mullite, wollastonite, cordierite, zircon porcelain, alumina, sapphire-ruby, beryllia, magnesia, thoria, titania, urania, zirconia)Space-age refractories (boron, nitride, glass cer-amics) Compatibility of ceramics with liquids, solids and gasesPermeation of gasesGen-eral techniques (fabrication, die construction and design considerations, glazing)Precision ceramics

3. Mica 118 MineralogyMining and preparationChemical and physical properties (thermal conductivity, thermal expansion, electrical resistivity, dielectric properties, the release of gas)General tech-niques (fabrication, splitting, sorting, casting, mounting, electrophoretic deposition)Syn-thetic mica Glass-bonded mica and ceramoplasticsReconstituted micaMica paper or mica mat, vs. built-up flake mica

4. Carbon and Graphite 137 Manufacturing processes (carbon black, industrial carbon, electrographite, pyrolytic graphite, recrystallized, high-density graphite, glassy carbon, cellulose carbon, fibrous carbon)Physical and chemical propertiesCompatibility with other materialsSpecial Processes and Applica-tions: Graphite anodesOutgassing of anodesMicrowave attenuatorsNuclear applications

5. Iron and Steel 160 The strength of materialsMechanical, physical, and chemical properties (the iron-carbon equi-librium diagram heat treatment)Commercial iron and steel (wrought stainless steels, marten-sitic stainless steels, ferritic stainless steels, austenitic stainless steels, semiaustenitic and precipi-tation hardening steels)Applications of stainless steelsSpecial Processes and Applications: Outgassing of iron and steelVacuum melting of iron and steelGas permeation in iron and steelRoll-clad iron and laminatesCopper-base Aliron

6. Copper and Copper Alloys 181 Physical characteristics and chemical properties (OFHC Brand copper, other high-purity cop-pers) Outgassing of copperCopper-base alloys (cupronickels, precipitation-hardenable al-loys, chrome copper, beryllium copper, zirconium copper)Dispersion strengtheningSpecial Processes and Applications: MachiningSpinningShot-peeningWater-cooled anodes Air-cooled anodesPinch-off tubulationsEffect of cold-working on r.f. conductivity

xii CONTENTS

7. Nickel and Nickel Alloys 204 Physical characteristics and chemical properties (Nickel 200, Nickel 201, Nickel 204, Nickel 205, Nickel 211, Nickel 212, Nickel 233, Nickel 270, Permanickel alloy, Duranickel alloy 301, Monel alloys)Outgassing of nickelSpecial Processes and Applications: Rolled-powder nickel Dispersion-strengthened nickelCarbonized nickelASTM specifications

8. Precious Metals and Their Alloys 222 (silver, gold, platinum metals and rhenium)

Physical characteristics and chemical properties (age-hardenable silver alloys, dispersion-strengthened silver alloys, dispersion-strengthened platinum alloys, precious metals and gases) Special Processes and Applications: High-temperature thermocouplesPrecious-metal con-tacts Precious-metal resistorsPlatinum-cobalt magnetsProtective and conductive coatings Rhenium

INTRODUCTION TO REFRACTORY METALS (RM) 9. Tungsten and Tungsten Alloys 249

Mechanical, physical, and chemical propertiesOxidation of tungsten-Tungsten alloys (tung-sten-tantalun and tungsten-molybdenum alloys, tungsten-rhenium alloys, other tungsten alloys) Special Processes and Applications: Non-sag filamentsThe forming of filamentsSlip cast-ing, centrifugal casting, hydrostatic densification, fluid-to-fluid extrusion, shape forming Vapor platingOxidation-resistant coatings

10. Molybdenum and Molybdenum Alloys 274 Methods of production (powder metallurgy, consumable-electrode or vacuum-arc melting, elec-tron-beam melting)Mechanical, physical, and chemical propertiesOxidation of molybde-num Protective coatingsMolybdenum AlloysSpecial Processes and Applications: Outgas-sing of molybdenumFabrication of molybdenum

11. Tantalum and Columbium (Niobium) and their Alloys 295 Mechanical, physical, and chemical properties of tantalumOxidationReactionsProtec-tive coatingsTantalum alloysSpecial Processes and Applications: OutgassingClad metals The fabrication of columbium and its alloysMechanical, physical, and chemical properties Special Processes and Applications: Cryogenic

12. Titanium, Zirconium, and Hafnium and their alloys 321 Titanium: Mechanical, physical, and chemical propertiesPhysical metallurgyTitanium al-loys Reactions with gasesZirconium and Hafnium: Mechanical, physical, and chemical propertiesSpecial Processes and Applications

INTRODUCTION TO JOINING PROCESSES 13. Soldering and Brazing 335

Physical principles (surface energy, contact angle, wetting and spreading, alloy formation and constitutional diagrams, diffusion, oxide reduction in reducing atmospheres)Soldering: solder compositions, aluminum solders, indium solders, gallium alloys, fusible alloys, solder fluxes, physical characteristics of solders, test procedures, soldering techniquesBrazing: Brazing metallurgy, the strength of brazed joints, filler metal compositions, brazing techniques, joint design, methods of heating, typical metal combinations (copper-to-copper, copper-to-nickel, copper-to-steel, copper-to-Kovar-type alloys, nickel-to-nickel)High-alloy-steel jointsSolid-state weldingRefractory metal joints (titanium and zirconium joints, beryllium joints) Graphite jointsOther welding processes

14. Glass-To-Metal Sealing 288 Classification of glass-to-metal sealsBond mechanismsStresses in sealsHouskeeper seals Induction sealsCompression sealsSealing to pure metals (platinum seals, gold and silver

CONTENTS xiii

seals, copper seals, tungsten seals, molybdenum seals, titanium and zirconium seals, tantalum seals)Sealing to alloys (iron and steel seals, nickel-iron alloy seals, chrome-iron seals, nickel-chrome-iron alloy seals, nickel-cobalt-iron alloy seals)Seal FabricationFused Quartz-to-metal sealsMicrowave window sealsSilver chloride seals

15. Ceramic-To-Metal Sealing 441 Advantages of ceramic sealsDisadvantages of ceramic sealsDesign considerationsSeal-ing techniques (dye check, cleaning procedures, sintered-metal-powder seals, low-temperature, sintered-metal-powder seals, active metal seals, pressed diffusion seals, soldered seals, vaporized and sputtered substrate seals, molten-salt titanium metallized seals, electroformed seals, graded powder seals, nonmetallic fusion seals)Bond formationTest procedures (mechanical tests, leak tests, electrical tests, environmental tests)Special Processes and Applications: Solution metallizingPin seals and headersHigh-temperature sealsCeramic seals for corrosive envir-onments Fusion bonding of ceramicsCompression band sealsBrazing considerations

16. Cathodes and Heaters 475 Thermal electron emissionCathode design parametersPure metal cathodes (pure tungsten cathodes)Thin film cathodes (thoriated tungsten, carburized thoriated tungsten filaments) Dispenser cathodes (nickel base, pressed and sintered cathodes, boride cathodes, thoria cath-odes) Barium, strontium, calcium-oxide cathodesPhysical characteristicsPreparation of the coatingExhaust procedureCathode ActivationPerformance and lifeNickel-base alloys for oxide cathodesFilamentary emittersHeaters (the coating of heaters, electrophor-etic coating of heaters and cathodes)The cataphoretic deposition of emissive coatings (the cataphoretic deposition of thoria)Physico-chemical effects in heater-cathode systems

17. Grid Structures and Coatings 529 Grid structures (receiving tube grids, frame grids, frame grids for disk-seal tubes)Suppression of primary electron emission from grids (graphite suspensions, gold plating, platinum-coated grids, titanium grids, other types of coatings) aluminum-clad molybdenumSpecial Processes and Applications: Ribbon gridsKlystron gridsEmbedded gridsNon-intercepting grids by partial suppression of cathode emissionCeramic-coated gridsCeramic gridsAligned gridsMesh screensPlating procedures for grid laterals

18. Getter Materials 545 Getter requirementsTypes of getter (flash getters, bulk getters and coating getters, tantalum, titanium, zirconium, zirconium alloys, thorium-thorium alloys)Special Processes and Applica-tions: Gas-doped flash gettersLarge-area metal filmsEvapor-ion and sputter-ion pumps

19. Secondary Emission 563 Physical characteristics (silver-magnesium alloys, magnesium alloys, nickel-beryllium alloys, nickel-magnesium alloys, copper-beryllium alloys, aluminum alloys)Suppression of secondary emissionSecondary-emission devicesSpecial Processes and Applications

20. Voltage Breakdown 579 Voltage breakdown in air (corona loss)Voltage breakdown over insulating surfacesVoltage breakdown through bulk dielectricsVoltage breakdown in vacuum (voltage breakdown mechanisms, design considerations)

Appendix 599

Index 613