Effects of Cr content on the interruption ability of CuCr contact materials

Li, W.P.; Thomas, R.L.; Smith, Richard C.

doi:10.1109/deiv.2000.879007

Cited by 12 publications

(15 citation statements)

References 11 publications

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“…Furthermore, the impact of Cr-content is also investigated, which was not conclusively reported by authors in the past e.g., in Refs. [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Microstructure Formation and Resistivity Change in CuCr during Rapid Solidification

Hauf

Kauffmann

Kauffmann-Weiss

et al. 2017

Metals

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Abstract:The formation of the surface-near microstructure after a current interruption of CuCr contact materials in a vacuum interrupter is characterized by a fast heating and subsequently rapid solidification process. In the present article, we reveal and analyse the formation of two distinct microstructural regions that result from the heat, which is generated and dissipated during interruption. In the topmost region, local and global texture, as well as the resulting microstructure, indicate that both Cu and Cr were melted during rapid heating and solidification whereas in the region underneath, only Cu was melted and elongated Cu-grains solidified with the <001>-direction perpendicularly aligned to the surface. By analysing the lattice parameter of the Cu solid solution, a supersaturation of the solid solution with about 2.25 at % Cr was found independent if Cu was melted solely or together with the Cr. The according reduction of electrical conductivity in the topmost region subsequent to current interruption and the resulting heat distribution are discussed based on these experimental results.

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“…Furthermore, the impact of Cr-content is also investigated, which was not conclusively reported by authors in the past e.g., in Refs. [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Microstructure Formation and Resistivity Change in CuCr during Rapid Solidification

Hauf

Kauffmann

Kauffmann-Weiss

et al. 2017

Metals

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“…The current was limited to about 35 kA for CuCr 30, 31.5 kA for CuCr 45, and 23 kA for CuCr 65. Compared with the VIs with CuCr 25 contacts (maximum 48 kA), CuCr contacts with a chromium content of 45 or 65 wt.% showed a strong decrease of the interruption ability from 35 kA (30 wt.%), nearly 100% of the current compared to CuCr 25, down to 23 kA for the 65 wt.% [4]. Fig.…”

Section: Figs 3 and 4 Show Results Of Test Procedures For The Differentmentioning

confidence: 82%

Multilayer contact material based on copper and chromium material and its interruption ability

Fink

Gentsch

Heimbach

2003

IEEE Trans. Plasma Sci.

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Contact material based on copper and chromium (CuCr) is widely used for vacuum interrupters (VIs) and has found worldwide acceptance in medium-voltage applications, especially for high-current interruption. Contact material with a weight content of chromium between 25 and 60 wt.% is almost exclusively used. A new contact material was established based on a multilayer system to improve the interruption ability and mechanical properties and reduce the contact resistance. After a combined sintering and melting process in a high-vacuum furnace, a material of high density and low gas content is produced. The finished blank consists of the following layers: CuCr-sheathing, copper bulk material, and a stainless-steel support resulting from the lost mold. It turned out that the higher thermal and electrical conductivity as well as mechanical properties of the multilayer contact material improved the interruption ability of the VI. Investigations of switching behaviors were carried out in standard VIs. Additionally, the standard chromium content of 25 wt.% in CuCr and the influence of higher chromium content was investigated with respect to interruption ability. Afterwards, the microstructure on the contact surface was analyzed with scanning electron microscopy and energy dispersive X-ray.

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“…Peoples tried to develop VI in the context of development of contact material, contact design, bellows, shields, insulating envelop design etc. [2,3]. Harald et.al.…”

Section: Introductionmentioning

confidence: 96%

Failure analysis of CuCr contacts of Vacuum interrupter

Zinzuwadia¹,

Maiti²,

Kulkarni³

et al. 2014

2014 International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV)

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The Copper-Chromium (CuCr) contact material is the most widely used material for the contacts of the vacuum interrupters (VI). Performance of the VI is greatly influenced by the properties of contact materials. During switching operations, such as short-circuit current interruption, a vacuum arc is generated which in turn produces melted and resolidified layers at the contact surface. Melting followed by welding of CuCr contact results the failure of Vacuum interrupter. This paper correlated the switching performance and the metallurgy of the contacts, specifically in cases where the contacts have welded. The paper reports important factors like microstructure, Cr distribution, conductivity, hardness etc. which significantly affect the welding performance of the contacts. The conductivity and hardness of the contacts were measured by using an eddy current based conductivity meter and Vickers hardness tester respectively. The failure of contacts because of welding has been discussed with respect to conductivity and distribution of Cr as seen in its microstructure. The contacts were also characterized by X-ray diffraction and scanning electron microscopy to correlate the data.

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Effects of Cr content on the interruption ability of CuCr contact materials

Cited by 12 publications

References 11 publications

Microstructure Formation and Resistivity Change in CuCr during Rapid Solidification

Microstructure Formation and Resistivity Change in CuCr during Rapid Solidification

Multilayer contact material based on copper and chromium material and its interruption ability

Failure analysis of CuCr contacts of Vacuum interrupter

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