Effects of Processing Methods on the Contact Performance Parameters for Silver-Tungsten Composite Materials

Leung, Chi-Hung; Bevington, R.; Wingert, P.C.; Kim, Han

doi:10.1109/tchmt.1982.1135948

Cited by 15 publications

(2 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These production routes may require different powder properties and compositions for optimum production, e.g., in the press-sinter process a sintering aid is generally required during the sintering process. However, to obtain a uniform microstructure in the contact with a fine tungsten particle size, a lower level of sintering aid has been recommended for their fabrication as shown by Leung et al (1982). The presssinter process is usually recommended for the production of medium heavy duty contacts as it is capable of producing a contact which contains finely dispersed silver and tungsten particles but such contacts often have lower densities than those produced by the press-sinter-infiltrate route and consequently have a higher erosion rate in service.…”

Section: Contact Fabricationmentioning

confidence: 99%

Sintering Characteristics of Iron and Cobalt Doped Silver-tungsten Metal-matrix Composites

Es-Saheb¹,

Azhar²,

Arabia³

2014

RJASET

View full text Add to dashboard Cite

Silver-Tungsten composites are known as electrical contact materials used in circuit breakers and industrial relays. The performance of the contact during their service life depends upon high strength and anti-weld properties of these materials. Despite their promising industrial applications, the literature dealing with their production route is still limited. Therefore, a comprehensive study exploring the structure related properties with great emphasis on the sintering process of these materials is carried out. Therefore, in this study, the successful production of a homogeneous composite powder with controlled tungsten particle size using co-precipitation and two stage reduction techniques is followed by the compaction and sintering processes. Thus, high density compacts are produced from Fe and Co doped silver-tungsten powder using powder metallurgy technique. Various environments and sintering conditions, including N 2 atmosphere and temperatures up to 1000°C, to obtain successful compacts from both doped and un-doped powders, are investigated. The morphologies and the microstructures of the sintered compacts obtained under the different sintering conditions are characterized and assessed using Scanning Electron Microscopy (SEM). Results display excellent agreement with the published studies and no evidence was found for the activated sintering of silver-tungsten by Fe additions. Also, the homogeneity of silver-tungsten in compacts is completely lost in the Fe-doped powders. However, Co additions help to facilitate the sintering between silver and tungsten whilst retaining a high homogeneity between the silver and tungsten in the sintered product.

show abstract

Section: Contact Fabricationmentioning

confidence: 99%

Sintering Characteristics of Iron and Cobalt Doped Silver-tungsten Metal-matrix Composites

Es-Saheb¹,

Azhar²,

Arabia³

2014

RJASET

View full text Add to dashboard Cite

show abstract

“…Aslanoglu et al [1] believed that the Ag-W alloys could only be prepared experimentally by powder metallurgy and obtained W-35 wt%Ag-1 wt%Ni alloy. Leung et al prepared Ag/W alloys by PSI technology and indicated that although it's the same with or without Ni microstructures, there was distinction in electric performances [2] . However, there are very few theoretical studies on the Ag-W system.…”

Section: Introductionmentioning

confidence: 99%

First-Principles Calculations of Elasticity Properties of AgW₂₀ Alloy

Liu

Du²,

Wang³

et al. 2023

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

In this paper, the first-principles calculations based on DFT were employd to investigate the elasticity characteristics of AgW20 alloy. The elasticity constants of the single crystals are calculated using the finite strain method and Voigt – Reuss – Hill (VRH) approach. The universal anisortropic index (AU ), shear anisortropic index, orientation dependency of Young’s modulus, bulk modulus were used to characterize elasticity anisortropy behaviors. The calculated elasticity properties of AgW20 alloy show a remarkable elasticity anisortropy for AgW20 alloy.

show abstract

Surface Degradation of Ag/W Circuit Breaker Contacts During Standardized UL Testing

Sun

Kesim

et al. 2015

J. of Materi Eng and Perform

View full text Add to dashboard Cite

The near-surface microstructure of Ag/W contacts from 120 V, 30 A commercial circuit breakers in the asmanufactured condition and after standardized UL overload/temperature-rise, endurance, and short-circuit testing have been investigated using a combination of x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray spectroscopy, focused ion beam milling, and transmission electron microscopy. The as-manufactured contacts comprised three constituents: sintered Ag/W composite particles with finegrained Ag and coarse-grained W, coarse-grained pockets of Ag infiltrate, and a nano-crystalline surface Ag layer. There are also WO 3 and Ag 2 O phases at the surface. After UL overload/temperature-rise testing, there is Ag loss giving a porous W-rich layer at the contact surface. In addition to binary oxides, we observe the formation of Ag 2 WO 4 . After UL endurance testing, material is swept across the surface by the breaker action giving a W-rich eroded porous surface on one side and a build-up of mixed oxides on the other. After UL short-circuit testing, a W crust forms due to melting and re-solidification of W and vaporization of Ag, and mid-plane cracks form due to the severe thermal gradients. There is a strong correlation between the observed microstructural features and the contact resistance measurements obtained from these samples.

show abstract

Effects of Processing Methods on the Contact Performance Parameters for Silver-Tungsten Composite Materials

Cited by 15 publications

References 4 publications

Sintering Characteristics of Iron and Cobalt Doped Silver-tungsten Metal-matrix Composites

Sintering Characteristics of Iron and Cobalt Doped Silver-tungsten Metal-matrix Composites

First-Principles Calculations of Elasticity Properties of AgW₂₀ Alloy

Surface Degradation of Ag/W Circuit Breaker Contacts During Standardized UL Testing

Contact Info

Product

Resources

About

Effects of Processing Methods on the Contact Performance Parameters for Silver-Tungsten Composite Materials

Cited by 15 publications

References 4 publications

Sintering Characteristics of Iron and Cobalt Doped Silver-tungsten Metal-matrix Composites

Sintering Characteristics of Iron and Cobalt Doped Silver-tungsten Metal-matrix Composites

First-Principles Calculations of Elasticity Properties of AgW20 Alloy

Surface Degradation of Ag/W Circuit Breaker Contacts During Standardized UL Testing

Contact Info

Product

Resources

About

First-Principles Calculations of Elasticity Properties of AgW₂₀ Alloy