P

Palladium, 245, 441, 521, 524, 537–538

contact resistance behavior of, 458

gold properties and, 686, 687

Palladium-based alloys, 1204

Palladium-based plated contacts, contact resistance of, 473

Palladium-based systems, 465–466

Palladium–nickel alloys, 460, 521, 524

Palladium–palladium contacts, 469, 471

Palladium plating, 245, 522

thickness, 523

Palladium rider sliding, 419

Palladium–silver alloys, 458

Palladium switching contacts, 940–942, 1204

palladium silver, 941

Palladium vs. gold alloys, 460–462

Palliative measures, power connectors, See Power connectors, palliative measures

Panel type connector, 378

Paper electrography, 528

Parabolic tarnish kinetic equation, 115

Parallel arc fault, 854

Paschen curves for air and SF₆, 564, 565, 855–856

Paschen’s law, 564

Passive Intermodulation (PIM) interference, 1112

PCBs, See Printed circuit boards

Percussion welding, 654–657, 903–904, 965

Perfluorinated polyether (PFPE), 180, 488

Perfluoroalkyl polyether fluid, 495–496

Permanent magnet (PM) motor, 1086, 1088

Permanent power fuse, 821

Permittivity vs. dust deposition density, 202, 203

Peroxides, 117

Petrolatum grease, 503

PFPE, See Perfluorinated polyether

Photoelectric emission, 566

Photovoltaic solar power systems, 637, 647–648

Piezoelectric actuation in MEMS, 705

PIM interference, See Passive Intermodulation interference

Pip and crater formation, 638, 757, 889, 901–902, 980

Pipe diffusion, 290, 296

Planck’s constant, 54

Plasma state, 554, 556, 826, See also Arc column

Plastic contact, 1161–1163

Plastic deformation, 239, 252

of asperities, 13, 77

creep and, 305

Plasticity index, 76

Plated contacts, 23, 131–132, 253–256, 414–505, 520–545

Plating-factor, 25

Platings

clad, 521

classification of, 244–246, 523–526, 688–689

copper, 245, 688

ENIG, electroless Ni and immersion Au, 423

gold, 245, 523, 714–715

hard gold, 523, 714

intrinsic polymers on hard gold, 525

iridium, 689

nickel, 245, 524

nickel alloys, 523–524, 689

other deposits, 525

palladium and palladium alloys, 245, 523–524, 714

platinum, 714

rhodium, 245, 714

ruthenium, 523, 714, 717

silver, 244, 524

tin, 525

tungsten, 689

contact resistance, 533, 543

electroless, 522

electrolysis, 522

fretting in, 286–287, 441–479

gold over carbon nano-tubes, 714–717

hardness, 523, 543–544

intermetallic, 539–541

Kerkendall porosity, 532

MEMS contacts, 713–720

porosity, See Porosity

power connectors, 246, 253, 331–333

reed relay contacts, 686–689

thermal effects, 532–539

substrate diffusion, 532

thickness of, 522–523

whiskers Sn and Ag, 541–542

Platinum-based alloys, 1204

Platinum plated contacts, 245

thickness, 523

Platinum switching contacts, 942–943, 1204

Plots of formative time lag vs. fractional over voltage, 571

Plowing, 419–421, 1104–1105

Pneumatic contactors, 794

Point-on-wave (POW), using Ag/CdO contact materials, 771–773

Polyglycol diproxamine D157, lubrication with, 177

Polymer-forming materials, 457

Polymers, 422, 451–452

Pore corrosion, 120–122, 153, 262, 526, See also Corrosion and Porosity

corrosion product, 114

Porosity, 131–133, 526–532

classic test, 423

corrision product, 114

origins of, 527

methods B735, B741B799, B809 (ASTM), 528

porous gold, 153, 161, 162, 423

properties related to, 526

tests of, 527–529

thickness of finish, and substrate roughness, 529–530

underplatings, flash coatings, and strikes on, 530–532

Position sensor connector, automotive, 402

Possible mechanism of energy transfer at cathode and anode, 584

Potential energy vs. distance for electron, 566

POW, See Point-on-wave

Powder metallurgical (PM), 887–890

Power connections, installation, 361–363

Power connectors, 133–134

automatic splices, 326–327

bolted, 236, 278–283

compression, 315–316, 344–345

dead end, 327

fired wedge, 343–344

insulation piercing, 236

intermetallics formation in, 298–299

physical model, 351

plug and socket, 236

prognostic models, 349–351

shape memory (SMA), 327–331, 351–355

Souriau, 354

stepped deep indentation, 315–316, 344–345

thermite welding, 339

types of, 234–236

wedge, 325

welded connections, 339–342

wire, 236

Power connectors, palliative measures, 264, 306

bimetallic inserts, 336–337

coating, 331–333

connector design, 342–345

contact area, 307–313

contact pressure, 313–320

disc-spring washers, 322–325

lubrication, 334–336

mechanical contact device, 320–322

multilam contact elements, 338–339

transition washers, 337–338

Power connectors, performance factors, 233, 247

aluminum and aluminum alloys, 243–244

contact area, 249–252

copper and copper alloys, 240–243

corrosion, See Corrosion

creep, See Creep, metal

current cycling tests, 315–316, 333, 345, 363–365

degradation, 345–348

elastic deformation, 253

electric current effect, 301–302

factors affecting reliability of, 247–249

fretting, See Fretting installation, 361–363

intermetallic compounds, See Intermetallic compounds

lubrication, 334–346

nut factor, 319

other metals, 244–246

oxidation, 256–260

plastic deformation, 252

plated contacts, 253–256, 331

power quality, 346–348

prognostic models, 349–351

reliability, 247–250

stress relaxation, See Stress relaxation

thermal expansion, 264–267, 321–322

thermoelastic ratcheting effect in bolted aluminum joints, 266

tightening torque, 318–320

testing, 363

Power quality, 346–348

disturbances, 347

harmonic distortions, 348

interruption, 348

sag, 348

swell, 348

transients, 347

Pre-impact arcing, 570, 631, 654, 775–776

Preoxidized metal oxide parts, 887

Pre-sliding phase, 1100, 1102

Pre-strike arc, 570, 631, 654, 775–776

Primary cathode spot parameters, 594

Primary interface interactions, 1098

Primary operating conditions for electromigration, 124

Printed circuit boards (PCBs), 423

Probability of anode spot formation, 594

Probe contacts, 543

Prognostic models for power connectors, 349–351

Progressive subsurface plastic deformation, 428

Prow formation, 415, 419–421, 437, 1103

Pure palladium, 537–538

Purple plague, 132

Q

Quantum-mechanical tunneling mechanism, 567

Quenching principles (arc)

contactors, 798–802

low-voltage circuit-breakers, 808–810

Quenching systems (arc), 787–788

R

Race theory of dielectric recovery, 599

Rack type connector, 378

Radial brushes, 1050

Radial stresses, 73

Radiation, low-voltage arcs simulation, 825–826

Radioactive tracer contact erosion measurement, 639, 640

Radio-frequency interference (RFI), 1087

Radio frequency microelectromechanical system (RF MEMS), 703

Real contact area, 15, 249–251, 1042

vs. apparent contact area, 15, 249, 1128

Reasonable noise specification, 1138

Recovery, stages of, 599–600

Reed relays and switches, 674–698

application examples, 698–701

contact plating, 686–689

contact adhesion prevention, 695–696

contact surface treatments 690–693

design principles, 674–685

drop-out characteristics, 682–683

ground plating layer, 687

magnet drive characteristics, 683–686

magnetic driven, 698–701

neutral position detection switch, 700

oxygen, 693

polymerization, 690

pull-in characteristics, 674–682

surface deactivation, 690–695

thermal, 701

Reflection high-energy electron diffraction (RHEED), 693

Reignition voltage, 599, 637, 800, 801, 832–834

arc chamber wall material effect, 799–800

Relative humidity (RH), 117–118, 126, 127

Residential low current arcing faults, 871

Residential wiring, 869

Residual resistivity, 238

Resistance brazing, 341–342

Resistance welding, 341

button welding, 962–963

contact tape welding, 963–965

wire-welding, 963

Restrike, 637, 790

Reynolds equation, 721

RFI, See Radio-frequency interference

RF MEMS, See Radio frequency microelectromechanical system

RF sensing method, 851, 852

RH, See Relative humidity

RHEED, See Reflection high-energy electron diffraction

Rhenium, 686

Rhodium, 245, 687, 690

Rhodium oxide (Rh₂O₃), 693–695

Rhodium-plating solution, 687

Richard-Dushman equation, 566

Rigid noncurrent-limiting breakers, 812

Ring a-spots, 7–11

Ring temperature, coefficient of friction vs., 1053, 1054

Rivets, See Contact rivets Rockwell hardness, 1196

Roughness, surface, 431

Round dots, 521

Ruthenium, 687–688

S

SAE, Society of Automotive Engineers, 377

Saha’s equation, 579, 603

SAMs, See Self-assembled monolayers

Scanning electron microscope (SEM), 29, 187, 716

Scanning electron microscopy with energy-dispersiveX-ray spectroscopy (SEM/EDAX), 129

Scanning Tunneling Microscope (STM), 1111, 1141

SCC, See Stress corrosion cracking

Scintillations, 855

Second Townsend coefficient, 563

Self-assembled lubricant layers, 500–503

Self-assembled monolayers (SAMs), 502

Self-healing, 504

of electrical contacts, 75, 96

process, 256

Self-induced fields, switch arc motion control, 998

SEM, See Scanning electron microscope

Series arcing, 855–857

Series-wound field motor, 1086

Servomotors, 758

SFA, See Surface forces apparatus

Shape-memory alloy (SMA), 351–355

connector devices, 327–331

and disc-spring washers, 329–331

Shape-memory effect (SME), 327

electronic application, 329

one-way, 352–353

origin of, 351–353

two-way, 353

Sharp contacts, 543

Sharvin resistance, 81, 83, 210, 708, 1110–1111

heating effect, 82

role in small aluminum-aluminum contacts, 86–87

Shear-induced ordering transitions, 1102

Sheet clad metal, 521

Shielding effects, 147

corrosion, 134

Short-circuit arcing, 854–855

Short-gap breakdown, 566–569

critical fields, 568

electron emission, 566

enhancement factor, 568

Showering arcs, 624–628

SI, International System of Units, 1207–1208

Signal quality, 1094

Silicone contamination, arcing contacts, 665–667, 1018–1030

film growth, 665–666

lower molecular weight fractions, 1019

lubricant, 1024

migration, contamination from, 666–667, 1023–1029

molecules, 665, 1022

SEM and EDX analysis, 1029

silicone migration, 665–667, 1023–1029

silicone vapors, 665–667, 1019–1023

types of, 1018

vapors, contamination from, 665–667, 1019–1023

Silver, 524, 1202

corrosion mechanisms, 151

corrosion rates, 145, 146

drawbacks of, 244–245

foam materials, 360–361

and silver alloys, 282–283

sulfide resistivity, 54, 141

Silver alloys, 1202

noble metals, See Noble metals

non-noble, See Non-noble silver alloys

silver and, 282–283

Silver-coated contacts, stability of, 287

Silver coatings, contact properties of, 339

Silver contacts, 638, 1202

voltage drop across, 642

silver-based alloy switching contacts, 937–938, 1202

silver-based switching contacts, 939, 1202

Ag-C, 943–945

Ag-Cu, 938

Ag-Ni, 939

Ag-Pd, 940

Ag-Pt, 942

Silver counterface, 1132

Silver-graphite brushes, 1084

Silver graphite switching contacts

anode and cathode, 944–945

dynamic welding, 944

erosion rate, 922

Silver metal oxide switching contacts, 802, 880–908, 1203

AC vs. DC testing, 890

contact resistance, 906–908

cracking, 904–906

erosion/arc, 632, 644, 896–902, 904–906

erosion/arc mobility, 906

erosion/materials transfer/welding, 899–902

erosion/mechanisms/cracking, 904–906

inductive loads, 890–891

internal oxidation, 884–889

interpreting Ag-CdO material research, 895–899

interruption characteristics, 800, 906

manufacturing technology, 884–895

materials

Ag-CdO, 883, 887

Ag-Fe2O3, 899

Ag-MgO-NiO, 883

Ag-SnO₂, 632, 644, 883, 889, 891–894

Ag-ZnO, 883, 898–899

silver–cadmium oxide vs. silver–tin oxide, 895

thermal arrest lines, 886

transfer/welding, 902–904

types, 883–884

welding, 902–904

Silver migration, 124

Silver nickel contact materials

electrical erosion, 939

manufacturing methods, 881

use, 793, 802

Silver-plating, 244, 332, 439, 524

thickness, 522–523

Silver-refractory metals, 908–935, 1203, 1205

arc erosion, 919

contacts, 659–664

contact resistance, 663, 928–935

electrical properties (EP), 918

graphite additions, 922

manufacturing technology/press sinter repress, 909–910

materials

Ag-Mo, 921, 1203

Ag-W, 908–922, 1203

Ag-WC, 921, 1203

Cu-W, 922, 1205

material properties, 908, 1203

material technology, 909–912

metallurgical/metallographic methods, 912–914

metallurgical/structure/strength and toughness, 914–918

oxides and tungstates, 663, 928–935

Silver–silver contacts, 450, 661

Silver sulfide, 141–142, 542

growth rate and electrical resistivity, 52–54, 142–143

Silver tungstates, 663, 930–935

Silver whisker, 542

Single controlled bounce, 656

Single-gas corrosion effects

chlorine, 163–164

gas flow effects, 165–168

hydrogen sulfide, 159, 161–162

temperature, 164–165

Single gas mixtures, 131

Single-wafer brush, 1090

Six VDC circuit, 639–640

mass transfer between contacts, 644

Skin effect/depth, 240

and constriction resistance, 89–95

electromagnetic penetration depth, 90

Sliding contacts for instrument control, 1094–1143

adhesion, 1102–1103

adhesive transfer, 1103–1104

adventitious lubrication, 1121, 1124

anaerobically lubricated contacts, 1122–1123

anaerobic vs. aerobic lubrication, 1121

assemblies, 1138–1141

cantilever composite brush, 1128–1129

cantilever metallic finger, 1129

cantilever wire brush, 1129–1130

channeling, 1124–1125

characteristics of, 1096–1097

conductivity, 1134

contact impedance, 1096, 1112–1113

contact resistance variation (noise), 1108–1109

contaminating environment, 1121

cylindrical surface, 1127

data integrity, 1114

direct effect torque, 1135

disjoining pressure, 1122

dynamic effects, 1107

electrical performance in, 1107–1108

excessive static friction, 1135

film formation on a-spots, 1115–1117

filming properties, 1134

film potentiometers, 1133

flammable fuels, submerged in, 1125

flat counterfaces, 1127

fluid-lubricated wire brushes in V-grooves, 1125

fretting, 1124

frictional polymers, 1124

friction and wear characteristics, 1135–1138

friction forces, 1100–1102

gas lubrication, 1125

groove configurations, 1127

guidelines, 1114

hard particle/three-body, 1105

inductance in contact region, 1114

low pressure and vacuum operation, 1125

lubrication, 1119–1121

lubrication modes, 1121–1125

macro, See Macro sliding contact

materials, 1132–1134, 1206

mechanical action, 1117

mechanical aspects, 1098–1099

micro-cuts, 1139

micro-environment of contact region, 1114–1115

micro-interrupts, 1139

molybdenum disulfide, 1125, 1133

motion continuation, 1102

motion initiation (pre-sliding), 1100

motion over time, 1105–1106

non-linear noise (frequency dependent), 1111–1112

non-ohmic noise, 1109–1111

numerical modeling, 1103

organic off-gasses, 1118–1119

over-lubrication of sliding electrical contacts, 1122

particulates, 1117

passive circuit elements, 1114, 1139

pin-on-disk contact, 1126

platter slip ring, 1140

plowing/two-body, 1104–1105

polymeric films, molecular re-ordering in, 1100

potentiometers, 1127

pressure, 1135

resistive effects, 1114

ring sliding system, 1056

sawtooth stick-slip curves, 1101

spring force, 1128

spring properties, 1134

stick-slip force, 1136, 1137

stick-slip process, 1101

temperature extremes, 1124–1125

tunnel resistance and vibration, 1048–1051

types of, 1044

unintentional contamination, 1117–1119

voltage drop, 1059

water molecules, 1118

Wexler’s formula, 1111

wire brush, 1129–1130

materials for, 1133–1134

Sliding contacts, metal fiber brushes, See Metal fiber brushes

adhesive wear, 1157–1158

arcing and bridge transfer, effect of, 1169–1170

critical/transition brush pressure, 1163–1164

film disruption, 1172

high wear regime, 160–161

Holm-Archard wear equation, 1158–1159

low wear equilibrium, 1159–1160

sliding speed effects, 1166–1169

steady state flash temperature, 1169

wear vs. brush pressure, 1164

Sliding graphite based contacts, 1042–1077

adhesive wear, 1048

atoms, layered structure of, 1074–1075

brush materials and abrasion, 1067, 1073–1076

brush wear, 1068–1073

chatter range, 1049, 1050

chemical aspects, 1051–1054

commutation, 1061–1063

contact area, 1042

contact resistance, 1055–1061

elastic penetration, 1047

electrical effects, 1055–1063

electrical noise, 1087

film resistance, 1055–1056

flashes, 1071–1073

friction-excited vibrations, 1049

graphite crystal structure, 1075

graphite, natural, 1075, 1083

Hertz’s formula, 1045

Holm’s law of wear, 1048

Holm’s wear equation, 1071, 1072

homo-polar bonds, 1074

ideal commutation, 1082

Kohlrausch-Holm Method, 1065–1066

mechanical aspects, 1044–1051

mechanical contact surface, 1064–1065

mechanical wear, 1070–1071

metal/graphite brushes, 1075–1076

moisture film, 1051–1054

monolithic fiber brush, 1076

occasional interruptions, 1072–1073

oil-lubricated sleeve bearing, 1068–1069

optimum brush, 1085

over-commutation, 1082

oxidation, 1051

particle transfer, 1048

residual current, arc duration and, 1061–1063

single contact, rupture of, 1042–1043

steady-state super temperatures, 1065

temperature effects, 1064–1068

thermal effects, 1064–1068

transfer and growth model, 1048

transfer wear model, 1048

transient effects in brush and collector applications, 1067

tunnel resistance, 1048, 1057

under-commutation, 1082

vibration, 1048

wear, 1068–1073

wear debris, 1107, 1141

wear resistance, 1134

Sliding motion, small-amplitude, 742

Sliding speed, effects of, 1166–1169

Sliding wear, 415

abrasion wear, 424–426

adhesion, 416–417

brittle fracture, 426–427

clad metals, 435–437

delamination and subsurface wear, 427–428

early studies, 415–416

electroless gold plating, 423

electroless nickel plating, 423

fretting, 441–448, See also Fretting

gold platings, 422–423

lubrication, 488–503

of multifiber brushes, 1156–1170

mild and severe, 418–419

prow formation, 419–421

rider wear, 421

silver, 439–441

tin and tin-lead alloys, 437–439

underplate and substrate, effect of, 428–431

underplate hardness, relationship of wear to, 431–435

unlubricated adhesive wear, 432

electrographic wear indexes from, 429

unlubricated palladium-palladium contacts, 487

wiping contaminant from contact surfaces, 417–418

Slip events, 1100

Slip rings, 1082, 1122, 1127

composite materials for, 1133

electrical model of, 1141

noise, 1109

as transmission lines, 1139–1140

SMA, See Shape-memory alloy

SME, See Shape-memory effect

Smutting, 1072–1073

Soft ductile metals, 419

Softening voltage, 95–96, 1198

Soft magnetic nickel-iron alloys, 246

Soft sticking, 695

Solid lubricants, 504

composite materials for brushes, 1133

Solid state vs. mechanical switches, high frequency circuits, 609–610

Solid 1st state of matter, 554

Space brushes, 1090–1091

Spark, 563

Sparkless commutation, 1086

Special brush holder, 1049, 1050

Speedometer switch, 700

Splitter plates, 603, 788, 801, 802, 824

Spreading resistance

calculation in thin film, 18–20, 709

remarks on calculation of, 20–22

Spring materials, 526, 1205–1206

Square a-spots, spreading resistance of, 10, 11

Stannic oxide (SnO₂), 49

Stannous oxide (SnO), 49

Starter motors, automotive, 1088–1089

Static vs. dynamic contact resistance, See Contact resistance

Static friction coefficient, 489

Static mechanical contact, 1095

Stationary anode spots, 608

Statistical time lag, 571

Steady state temperature distribution, closed contacts, 65, 103–104

STM, See Scanning Tunneling Microscope Streak technique, 996

Streamline effect, 307–309

Stress corrosion cracking (SCC), 124–125

Stress relaxation, 299–305

electric current effect on, 302–305

and metal creep, 305–306

static vs. dynamic, 267

Strikes effect on porosity, 530–531

Stylus profilometer, 757

Substrate

effect of underplate and, 428–431

role of underplate and, 467–468

roughness, porosity and, 529–531

Subsurface wear, 427–428

Sulfur dioxide (SO₂), 117, 131, 163

Superconductors, 821–822

Superficial initial oxides, mechanical disruption of, 452

Supplementary organic lubricant, 485

Surface deactivation treatment, 690–691

life test of samples, 691–695

Surface film effects, 141

on constriction and contact resistance, 18

electrically insulating/weakly conducting, 45–47

Surface films, 393–396, 1107, 1170–1173

Surface forces apparatus (SFA), 1157

Surface micro-roughness, 4

Surface penetration, 1047

Surface pressure, 1045

Surface profile

measurement of, 756–757

using non-contact laser probe, 757

Switch arc motion control, 998–999

Switches, low current, 733–781

AC current erosion, 720–723

actuated, 739–741

bounce times, 752–754

DC current erosion, 755–753

design, 779

change-over configuration, 735–737

change-over time, 744–746

classification, 733–734

coefficient of restitution, 749–751

contact bounce, 779

contact force, 742–743

contact welding on make, 774–775

“hair spring” configuration, 736, 737

hand-operated, 734–739

hand-operated rocker-switch mechanism, 744–746

impact mechanics, 748–749, 752

impact times, 755

lever, 737

low-current alternating current arcs, 768–770

low-current direct current arcs, 761–765

low current, electrical characteristics on closing, 773–774

make-down configurations, 735, 736

make operation, 747–748, 780–781

make-up configurations, 735, 736

membrane switches, 739

normal operation, rocker-switch, mechanism, 744

on-off configuration, 735, 736

opening characteristics, switching devices, 746–747

pivoting mechanism, impact mechanics for, 751–752

pre-impact arcing, 775–776

push-button switches, 738–739

remote control switches, 794

rocker-switch mechanism, 734–737

rotary switches, 738

slide switches, 738

snap action, 735

soft action, rocker type, 744

static design parameters, 741–743

switching devices, 739

thermostatic control switch, 740–741

velocity influence, during first bounce, 777–778, See also Point-on-wave (POW)

Switching of d.c. circuits, See Arc interruption

Synthetic graphites, 1083

T

Tabor equation, 1174

Tangential brushes, 1180

Tangential fiber brush, 1154–1156

Tangential forces, 1100

Tarnish films, 129, 256–260

observation and analysis of, 117–118, 129, 140–143

reaction, 114

tarnish rates, 114–116, 145

Teflon-thickened greases, 503–504

Tellurium oxide, 891–892

TEM, See Transmission electron microscopy

Temperature-dependent ceramics/polymers, 821

Temperature-dependent electrical resistivity, voltage-temperature relation with, 60–62

Temperature distribution in a-spot vicinity, 63–64

plane of maximum value, 100–104

Temperature vs. voltage, in asymmetric contact, 64, 1066

Ten-finger parallel contacts, 649

Tensile strength, hardness and, 651

cold working, 651

Terminal position assurance (TPA), 383

Testing switching contacts

AC vs. DC, 978

bounce, 980

contact resistance, 982

device vs. model, 976, 988

erosion, 981

load type, 974

motion, 996

welding, 989

Tests of porosity, 527–529

Test systems, mixed-gas environments, 169

T–F electron emission, See Electron emission

Thermal conductivity, 1198

constants, 68

of metals and Wiedemann–Franz Law, 96–100

voltage-temperature relation with, 60–62

Thermal diffusion in platings, 532–539

Thermal expansion

coefficients, 321–322, 1199

power connectors, 264–267

Thermal-magnetic (T-M) breaker, 850–851

Thermal reignition, 603–604

power balance equations, 604

Thermal runaway effect, 65–69

Thermionic emission, 566, 600

Thermionic reignition, 603

Thermoelastic ratcheting effect in bolted aluminum joints, 266

Thin contaminant films, electrically conducting layers and, 23–28

Thompson effect, 638–639

Three-body abrasion, 424, 425

Three dimensional (3–D) surface measurement systems, 757–758

Three-gas tests, 168

Tin

coatings, 525, 539

corrosion mechanisms, 152

oxide and resistivity, 54, 141

plating thickness, 521

properties, 1198–1201

as terminal coating material, 393

and tin alloys, 280–282, 437–439

whiskers, 541–542

Tin and tin–lead alloy systems, 466–467

Tin-base coatings vs. tin-base surfaces, 453–456

Tin-based contacts, degradation of, 439

Tin Commandments, 133–134

Tin contacts, classical electrical contact theory in, 88–89

Tin–copper interfaces, intermetallic growth in, 40–41

Tin–lead alloy, 420, 539–540

Tin–lead-coated checkerboard surface, 479

Tin oxide, growth rate and electrical resistivity, 49–50

Tin-plated contact regions, surface morphology of, 454–455

Tin-plated copper contacts, surface morphology of, 466–467

Tin-plating, 331, 525

thickness, 522–523

Tin–tin contacts, 134

degradation of, 478

T-M breaker, See Thermal-magnetic breaker

Torch brazing, 967

Torque, 318–320

nut factor, 319

Townsend avalanche, 561

Townsend breakdown, 563

TPA, See Terminal position assurance

Transient recovery voltage (TRV), 598, 798, 831

Transients, power quality issues, 347

Transition washers, 337–338

Transmission electron microscopy, (TEM), 1111

Transverse magnetic field, 596

Transverse magneto resistance, 240

Transverse rupture strength (TRS), 916

Trip system, 814–815

TRS, See Transverse rupture strength

TRV, See Transient recovery voltage

Tungsten, 245

Tungsten contacts, 689, 718, 936–937

Tungsten–silver contacts, 659–665, 908–928

Tungsten–silver microstructure, 913

Tunnel effect, 566–567, 1056

Tunnel resistance, 713

and vibration, 1048–1051

Turbo-generator brushes, 1090

Two-body abrasion, 424, 427, 433

Two-body abrasive wear, electrographic wear, indexes from, 430

Type I (Unstable) contact resistance, behavior, 449–452

Type II (Intermediate) contact resistance behavior, 449–452

Type III (Stable) contact resistance behavior, 449–452

U

Underwriters Laboratory, (UL), 327, 794, 806

Ultrasonic cleaning, 225

Underplate

effect of, 530–531

nickel, See Nickel underplate

reduction in chemical reactivity of finishes by, 531–532

Unintentional contamination, 1117–1119

Universal motors, 1085–1086

Unmated exposures, mated vs., 172–174

US type miniature circuit-breaker, 815–816

V

Vacuum arc, 578, 828

anode spot, 594

axial magnetic field, 596–597, 832

cathode spots, 593–594

columnar, 595

diffuse, 592–595

formation, 592–593

interruption in alternating circuits, 607–608

modes, 595

and short-gap breakdown, 566–569

transverse magnetic field, 596, 832

Vacuum breakdown, 566–569, 602

critical fields, 568

electron emission, 566

enhancement factor, 568

metal vapor, 567–568

Vacuum contactors, 805, 830

Vacuum circuit breakers, 831

Vacuum interrupter contact materials

chop current, 836, 838–389

chrome–copper, 836, 936, 1210

other suggestions, 836

requirements, 835

tungsten–copper/tungsten carbide–silver, 836, 935–936, 1210

Vacuum interrupters

design, 829–831

principle/applications, 828–829

recovery and influence of design, 607, 831–839

simulation of arcs in, 839–840

Van der Waals force, 1119

Vapor deposition, 393

Vapor phase corrosion inhibitors (VCIs), 180

Verband der Elektrotechnik (VDE), 794

Velocity effects

opening and closing, 980

switches, make operation, 752

Velocity factor (VF), 871

Velocity strengthening, 1102

Vertical free burning arc, 580

VF, See Velocity factor

Vibration, corrosion effect, 180

Vickers hardness (VH), 1196

Visual inspection of corrosion, 129

Voltage characteristics of molten metal bridge, 573

Voltage–current characteristics

for free burning, 589, 590

function of contact gap, 591

for gas breakdown, 570

of separated contacts, 569–570

Voltage regulator, 1088

Voltage–temperature relation, 5, 58–60, 96, 572, 723

deviation in assymetric contact, 64–65

with temperature-dependent electrical

resistivity and thermal conductivity, 60–62

validity of, 84

Volumetric erosion, 758–761

W

Water-sealing products, 343

Water soluble salts, 192–193

Water vapor, 1125, See also Humidity

in saturated air, 1209

Weakly conducting films, 45–47

Wear, 415, 1047–1048, 1071, See also Sliding wear; Fretting

abrasion, 424–426

adhesion, 416–417

clad metals, 435–437

delamination and subsurface wear, 427–428

delamination mechanism of, 271, 481

equation, 415, 1048

gold platings, 422–423

mild and severe, 418–419

prow formation, 419–421

rate, reduction in, 496–497

rider wear, 421

stages in, 438

tin and tin–lead alloys, 437–439

underplate and substrate, 428–431

to underplate hardness, relationship of, 431–435

unlubricated adhesive wear, 432

electrographic wear indexes from, 429

unlubricated palladium–palladium contacts, 487

Wear characteristics, 1137–1138

Wear debris, 1107, 1141

Wear resistance, 1134

Wedge-flow mechanism, 437

Weibull distribution, 986

Weight gain measurements of corrosion, 129

Welded connections, 339–342

Welded contact assembly designs

components, 960, 961

friction welding, 966

parameters of, 961–962

percussion welding, 965

resistance welding, See Resistance welding

special welding methods, 965–966

ultrasonic welding of, 965–966

Weld force, 654–657

Welding

of closed contacts, 651–654

current level, 652, 811

as contacts close, 654–657

as contacts open, 657

dynamic welding, 654–657, 902–903

measurement, 989–981, 992

silver metal oxide materials, 904

static welding resistance, 902

switching contacts, See Contacts switching

Wexler’s formula, 1111

Whiskers

silver, 542

tin, 541–542

White plague, 132

Wiedemann–Franz law, 62–63, 96–100, 477

electrical resistivity and thermal conductivity, 96–100

Wipe cleaning motion, 417

Wiping, 459, 1095

contacts, sliding and, 482–486

motion, 742

Wire connectors, 236

Wire materials, 864, 865

Wire–screw terminal, 385–386

Wire-welding, 963

Wire–wire twist terminal, 384–385

Wire-wound potentiometers, 1133

Work hardening

first bounce, 777

switches, make operation, 750

Worst-case office air condition, 145

Wound field magnet motor, 1086, 1088

Wrought metals, 521–522

Wrought noble contact metals, 426

X

XES, See X-ray energy spectroscopy

XPS, See X-ray photoelectron spectroscopy

X-ray diffraction analysis of fretting debris, 280

X-ray energy spectroscopy (XES), 188

X-ray photoelectron spectroscopy (XPS), 129, 272, 693, 695

Y

Yielding, See Deformation

Yield stress vs. hardness, 250, 651

Young’s modulus, 681

of elasticity, 1045

Z

ZCA, See Zone of closest approach

Zero-insertion-force (ZIF), 383

ZOI, See Zone of influence

Zone of closest approach (ZCA), 1098

Zone of influence (ZOI), 1120

Zone selective interlocking (ZSI), 871