Tungsten and tungsten carbide based contact materials used in low voltage vacuum contactors

Behrens, V.; Honig, Thomas; Kraus, A. E.

doi:10.1109/holm.1999.795934

Cited by 8 publications

(3 citation statements)

References 4 publications

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“…The basic process of AgWC material is: powder mixing, granulating, compacting, sintering, infiltrating and after-treatment [1][2][3]. A JEOL JSM-6390A scanning electron microscopic was used to check the fracture morphology, and a SANS-CMT universal testing machine was used to measure the fracture resistance.…”

Section: Methodsmentioning

confidence: 99%

“…AgWC material, which is generally produced by high temperature infiltration [1][2][3], is widely adopted as moving contact in low voltage apparatus for its excellent anti-erosion and antioxidation abilities [4][5][6][7][8][9][10][11][12][13][14]. However because of the poor wettability between WC and Ag (Wetting angle about 30°), the infiltration process often meets with difficulties [15], creates internal defects of contact material which greatly increase the risk of electrical aperture failure [1].…”

Section: Introductionmentioning

confidence: 99%

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Investigation on the mechanism of the infiltration process of contact material

Song¹,

Zhang²,

Bai³

et al. 2015

2015 IEEE 61st Holm Conference on Electrical Contacts (Holm)

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The transport of liquid metal throughout skeleton is the core process of infiltration of contact material. In the case of silver tungsten carbide (AgWC), we discussed the mechanism of liquid silver (Ag) transport based on the morphology of product structure after each manufacturing process recorded by scanning electron microscope. Analysis shows that the transport of liquid Ag is mainly influenced by the 'transport dynamic', which is determined by interfacial energy between Ag and tungsten carbide (WC)， and the 'transport corridor', which represents the distribution of the pore network in skeleton. It is shown that either to enhance the 'transport dynamic' or to broaden the 'transport corridor' will significantly improve the infiltration process, therefore increase the anti-erosion ability of AgWC material. I.978-1-4673-9341-6/15/$31.00 ©2015 IEEE

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation on the mechanism of the infiltration process of contact material

Song¹,

Zhang²,

Bai³

et al. 2015

2015 IEEE 61st Holm Conference on Electrical Contacts (Holm)

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“…Silver based metal matrix refractory composites have been of considerable interest to the electrical industry for making electrical contacts, which are employed in circuit breakers [1][2][3] and vacuum contactors [3,4] as an arc-resistant material. The addition of refractory carbides and/or metals like WC and W to the silver matrix has resulted in enhancing the desired properties of these materials.…”

Section: Introductionmentioning

confidence: 99%

Effect of WC particle size and Ag volume fraction on electrical contact resistance and thermal conductivity of Ag–WC contact materials

et al. 2015

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In this work, theoretically dense (N 99%) composites of Ag and WC have been prepared by press-sintering-infiltration for making electrical contacts used as an arc-resistant material in a model switching device. Composites with varying silver content and WC particle size were investigated to get an insight on their electrical contact resistance (R c ) and their ability to withstand enormous thermal stresses during switching. A break-only model switching sequence was used, where the evolution of R c was measured over 50 cycles and the post-switching microstructures were investigated for thermal stress induced crack formation. A well-established 2D computational microstructure based model, object-oriented finite element analysis version 2 (OOF2), was used to determine the composite thermal conductivity (k) for various grades as a function of temperature. R c was observed to be consistently low for the coarser WC containing composite and higher silver content composites. This response was attributed to the ductility of the surface layers formed during switching. Crack formation after switching was found to be a direct consequence of large thermal gradients during 50 cycles, which was minimal for coarser WC grained and higher silver content composites which have a higher thermal shock resistance.

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Tungsten Carbides

Shabalin

2022

Ultra-High Temperature Materials IV

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Tungsten and tungsten carbide based contact materials used in low voltage vacuum contactors

Cited by 8 publications

References 4 publications

Investigation on the mechanism of the infiltration process of contact material

Investigation on the mechanism of the infiltration process of contact material

Effect of WC particle size and Ag volume fraction on electrical contact resistance and thermal conductivity of Ag–WC contact materials

Tungsten Carbides

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