Preliminary Measurements of Electrical Micropitting in Grease-Lubricated Point Contacts

The dielectric breakdown characteristics of three types of grease used in motors are compared by direct observations of flashes caused by the electric discharge between surfaces composed of a steel ball and a glass disc coated with chromium and indium tin oxide films. The flashes produce pitting on...

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Published inTribology transactions Vol. 54; no. 5; pp. 730 - 735
Main Authors Sunahara, Kenji, Ishida, Yuji, Yamashita, Shinji, Yamamoto, Masaharu, Nishikawa, Hiroshi, Matsuda, Kenji, Kaneta, Motohiro
Format Journal Article
LanguageEnglish
Published Philadelphia, PA Taylor & Francis Group 01.09.2011
Taylor & Francis
Taylor & Francis Inc
Subjects
Applied sciences
Chromium
Contact of materials. Friction. Wear
Dielectric breakdown
Dielectric properties
Discs
Disks
EHL
Electrical Pitting
Exact sciences and technology
Friction, wear, lubrication
Glass
Greases
Indium tin oxide
Lubricating greases
Machine components
Materials fatigue
Mechanical engineering. Machine design
Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology
Melting
Metals. Metallurgy
Motors
Steels
Lubricating oil
Point contact
Melting
Oxide layer
Surface crack
Glass
EHL
Electrical Pitting
Metal
Layer thickness
Electric discharge
Lubricating grease
Thickener
Corrosion
Chromium oxide
Ball bearing steel
Greases
Micropitting
Erosion
Elastohydrodynamic lubrication
Tribology
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Summary:The dielectric breakdown characteristics of three types of grease used in motors are compared by direct observations of flashes caused by the electric discharge between surfaces composed of a steel ball and a glass disc coated with chromium and indium tin oxide films. The flashes produce pitting on the steel ball and coated glass disc surfaces. It has been found that the frequency of the flash signal depends on the film thickness. It has also been found that the dielectric breakdown of greases is mainly influenced by the base oil rather than the thickener. Furthermore, it has been proved through the calculation of electrical energy brought by the flash or dielectric breakdown that the pitting is caused by melting of the steel surface due to a concentration of the electric current.
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:1040-2004
1547-397X
DOI:10.1080/10402004.2011.597543