The transition from the molten bridge to the metallic phase bridge column arc between electrical contacts opening in vacuum

2008 ◽  
Author(s):  
Paul G. Slade
Keyword(s):  
Metallic Phase ◽  
Electrical Contacts ◽  
Bridge Column

Investigation on Microstructure Transformation and Failure Behavior of Cu-Cd-Nb-CP Electrical Contact Material

2005 ◽  
Vol 475-479 ◽  
pp. 869-872
Author(s):  
Yu Sheng Cui ◽  
Wen Zhu Shao ◽  
L. Zhen ◽  
V.V. Ivanov
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Electrical Contact ◽  
Optical Microscope ◽  
Metallic Phase ◽  
Electrical Contacts ◽  
Failure Behavior ◽  
Contact Material ◽  
Electrical Contact Material ◽  
Micro Cracks

Dependence of microstructure upon transfer stability of the powder-metallurgy copperdiamond electrical contact material with Cr and Nb addition during type-test process is investigated by optical microscope and SEM observation. During making and breaking process, micro-cracks occurred along grain boundaries under electrical and mechanical forces. Addition of cadmium into the composite increases oxidizable capability of this material, and also leads to oxide accumulation along grain boundaries. These factors reduce the reliability of electrical contacts in practice. Arc erosion quantities during commutation operation processes relates with grain size of matrix and particle size of the second metallic phase. The optimal grain size is 20~50µm and 10~20 µm for niobium particles in these tests.

Conductive Atomic Force Microscopic (C-AFM) Studies of Au/MoS2 Nanocomposite Films

2005 ◽  
Author(s):  
Hyun I. Kim ◽  
Jeffrey R. Lince
Keyword(s):  
Morphological Changes ◽  
Real Space ◽  
Metallic Phase ◽  
Electrical Contacts ◽  
Sliding Contact ◽  
Nanocomposite Films ◽  
Material Transfer ◽  
Atomic Force ◽  
Gradual Disappearance ◽  
Slip Rings

Au/MoS2 nanocomposite films with high Au concentrations (75 to 90 at%), recently developed at The Aerospace Corp., have shown properties that are promising for use in sliding electrical contacts, such as slip rings and relays. For such applications, it is critical to maintain low contact resistance while maintaining low friction with controlled wear (i.e. removal and transfer of material). In this report, we present results from conductive atomic force microscopic (c-AFM) investigations of Au/MoS2 nanocomposite structures and their dynamic material transfer phenomena under a sliding contact, which are both important in understanding the friction, wear and conducting mechanisms of the films. We have performed c-AFM to obtain topography, friction and current images simultaneously. Remarkable morphological changes were observed in a series of current images which initially showed distinct nanoscale metallic (Au) and semiconducting (MoS2) phases that were relatively well dispersed, but repeated contact sliding in the same area resulted in gradual disappearance of the metallic phase and reduction of the overall friction. These results reveal that MoS2 is transferred across the surface to provide lubrication while Au particles at or near the surface provide electrical conductivity. The c-AFM results provide real-time and real-space visualization of the lubrication mechanism occurring inside a nanoscale sliding contact.

Dynamic studies of silicide-mediated crystallization of amorphous silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1352-1353
Author(s):  
C. Hayzelden ◽  
J. L. Batstone
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Metallic Phase ◽  
Single Crystal Substrate ◽  
Free Electrons ◽  
Melt Temperature ◽  
Transmission Electron ◽  
Crystal Substrate ◽  
High Resolution Tem

Epitaxial reordering of amorphous Si(a-Si) on an underlying single-crystal substrate occurs well below the melt temperature by the process of solid phase epitaxial growth (SPEG). Growth of crystalline Si(c-Si) is known to be enhanced by the presence of small amounts of a metallic phase, presumably due to an interaction of the free electrons of the metal with the covalent Si bonds near the growing interface. Ion implantation of Ni was shown to lower the crystallization temperature of an a-Si thin film by approximately 200°C. Using in situ transmission electron microscopy (TEM), precipitates of NiSi2 formed within the a-Si film during annealing, were observed to migrate, leaving a trail of epitaxial c-Si. High resolution TEM revealed an epitaxial NiSi2/Si(l11) interface which was Type A. We discuss here the enhanced nucleation of c-Si and subsequent silicide-mediated SPEG of Ni-implanted a-Si.Thin films of a-Si, 950 Å thick, were deposited onto Si(100) wafers capped with 1000Å of a-SiO2. Ion implantation produced sharply peaked Ni concentrations of 4×l020 and 2×l021 ions cm−3, in the center of the films.

TEM characterization of Au/Polysilicon interactions

1990 ◽  
Vol 48 (4) ◽  
pp. 650-651
Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Solid Phase ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Transmission Electron ◽  
Polysilicon Films ◽  
The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

Metallic phase stabilization and phase diagram of (ET)3(HSO4)2

1991 ◽  
Vol 1 (10) ◽  
pp. 1365-1370 ◽  
Author(s):  
N. D. Kush ◽  
V. N. Laukhin ◽  
A. I. Schegolev ◽  
E. B. Yagubskii ◽  
E. Yu. Alikberova ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Metallic Phase ◽  
Phase Stabilization

DEGREE OF VALENCE MIXING IN THE METALLIC PHASE OF SmS AND IN TmSe

1976 ◽  
Vol 37 (C4) ◽  
pp. C4-267-C4-270 ◽  
Author(s):  
B. BATLOGG ◽  
A. SCHLEGEL ◽  
P. WACHTER
Keyword(s):  
Metallic Phase ◽  
Valence Mixing

CRM MOLYBDENUM-50 RHENIUM

Alloy Digest ◽  
1970 ◽  
Vol 19 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Powder Metallurgy ◽  
Melting Point ◽  
Physical Properties ◽  
Heat Treating ◽  
Electrical Contacts ◽  
High Melting ◽  
High Melting Point ◽  
Temperature Performance

Abstract CRM MOLYBDENUM-50 RHENIUM is a high-melting-point alloy for applications such as electronics tube components, electrical contacts, thermionic converters, thermocouples, heating elements and rocket thrusters. All products are produced by powder metallurgy. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Mo-11. Producer or source: Chase Brass & Copper Company Inc..

Sign in / Sign up

Export Citation Format

Share Document