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 glass—The composition of glass—Gas permeation through glass—The mechan­ical strength of glass—Chemical strengthening of glass—The annealing of glass—Stress analy­sis— Volume conductivity—Electrolysis in glass—Surface conductivity—Dielectric properties —Glass in radiation fields—Special Processes and Applications: Manipulation—Cutting and polishing of small holes—Thin glass windows—Glass sheet and films—Glass shrinking— Cleaning of glass—Particulate contamination—Outgassing—Powdered glass—Solder 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 cer­amics)— Compatibility of ceramics with liquids, solids and gases—Permeation of gases—Gen­eral techniques (fabrication, die construction and design considerations, glazing)—Precision ceramics

3. Mica 118 Mineralogy—Mining and preparation—Chemical and physical properties (thermal conductivity, thermal expansion, electrical resistivity, dielectric properties, the release of gas)—General tech­niques (fabrication, splitting, sorting, casting, mounting, electrophoretic deposition)—Syn­thetic mica— Glass-bonded mica and ceramoplastics—Reconstituted mica—Mica 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 properties—Compatibility with other materials—Special Processes and Applica­tions: Graphite anodes—Outgassing of anodes—Microwave attenuators—Nuclear applications

5. Iron and Steel 160 The strength of materials—Mechanical, physical, and chemical properties (the iron-carbon equi­librium diagram heat treatment)—Commercial iron and steel (wrought stainless steels, marten-sitic stainless steels, ferritic stainless steels, austenitic stainless steels, semiaustenitic and precipi­tation hardening steels)—Applications of stainless steels—Special Processes and Applications: Outgassing of iron and steel—Vacuum melting of iron and steel—Gas permeation in iron and steel—Roll-clad iron and laminates—Copper-base Aliron

6. Copper and Copper Alloys 181 Physical characteristics and chemical properties (OFHC Brand copper, other high-purity cop­pers)— Outgassing of copper—Copper-base alloys (cupronickels, precipitation-hardenable al­loys, chrome copper, beryllium copper, zirconium copper)—Dispersion strengthening—Special Processes and Applications: Machining—Spinning—Shot-peening—Water-cooled anodes— Air-cooled anodes—Pinch-off tubulations—Effect 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 nickel—Special Processes and Applications: Rolled-powder nickel— Dispersion-strengthened nickel—Carbonized nickel—ASTM 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 thermocouples—Precious-metal con­tacts— Precious-metal resistors—Platinum-cobalt magnets—Protective and conductive coatings — Rhenium

INTRODUCTION TO REFRACTORY METALS (RM)

9. Tungsten and Tungsten Alloys 249 Mechanical, physical, and chemical properties—Oxidation of tungsten-Tungsten alloys (tung-sten-tantalun and tungsten-molybdenum alloys, tungsten-rhenium alloys, other tungsten alloys) — Special Processes and Applications: Non-sag filaments—The forming of filaments—Slip cast­ing, centrifugal casting, hydrostatic densification, fluid-to-fluid extrusion, shape forming— Vapor plating—Oxidation-resistant coatings

10. Molybdenum and Molybdenum Alloys 274 Methods of production (powder metallurgy, consumable-electrode or vacuum-arc melting, elec­tron-beam melting)—Mechanical, physical, and chemical properties—Oxidation of molybde­num— Protective coatings—Molybdenum Alloys—Special Processes and Applications: Outgas­sing of molybdenum—Fabrication of molybdenum

11. Tantalum and Columbium (Niobium) and their Alloys 295

Mechanical, physical, and chemical properties of tantalum—Oxidation—Reactions—Protec­tive coatings—Tantalum alloys—Special Processes and Applications: Outgassing—Clad metals —The fabrication of columbium and its alloys—Mechanical, physical, and chemical properties— Special Processes and Applications: Cryogenic

12. Titanium, Zirconium, and Hafnium and their alloys 321 Titanium: Mechanical, physical, and chemical properties—Physical metallurgy—Titanium al­loys— Reactions with gases—Zirconium and Hafnium: Mechanical, physical, and chemical properties—Special 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 techniques—Brazing: 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 joints—Solid-state welding—Refractory metal joints (titanium and zirconium joints, beryllium joints)— Graphite joints—Other welding processes

14. Glass-To-Metal Sealing 288

Classification of glass-to-metal seals—Bond mechanisms—Stresses in seals—Houskeeper seals — Induction seals—Compression seals—Sealing 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 Fabrication—Fused Quartz-to-metal seals—Microwave window seals—Silver chloride seals

15. Ceramic-To-Metal Sealing 441

Advantages of ceramic seals—Disadvantages of ceramic seals—Design considerations—Seal­ing 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 formation—Test procedures (mechanical tests, leak tests, electrical tests, environmental tests)—Special Processes and Applications: Solution metallizing—Pin seals and headers—High-temperature seals—Ceramic seals for corrosive envir­onments— Fusion bonding of ceramics—Compression band seals—Brazing considerations

16. Cathodes and Heaters 475

Thermal electron emission—Cathode design parameters—Pure 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 cath­odes)— Barium, strontium, calcium-oxide cathodes—Physical characteristics—Preparation of the coating—Exhaust procedure—Cathode Activation—Performance and life—Nickel-base alloys for oxide cathodes—Filamentary emitters—Heaters (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 molybdenum—Special Processes and Applications: Ribbon grids—Klystron grids—Embedded grids—Non-intercepting grids by partial suppression of cathode emission—Ceramic-coated grids—Ceramic grids—Aligned grids—Mesh screens—Plating procedures for grid laterals

18. Getter Materials 545

Getter requirements—Types of getter (flash getters, bulk getters and coating getters, tantalum, titanium, zirconium, zirconium alloys, thorium-thorium alloys)—Special Processes and Applica­tions: Gas-doped flash getters—Large-area metal films—Evapor-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 emission—Secondary-emission devices—Special Processes and Applications

20. Voltage Breakdown 579

Voltage breakdown in air (corona loss)—Voltage breakdown over insulating surfaces—Voltage breakdown through bulk dielectrics—Voltage breakdown in vacuum (voltage breakdown mechanisms, design considerations)

Appendix 599

Index 613