Method and device for determining the thickness of an electrically conductive layer
US6040694A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 22, 1998 |
| Grant date | Mar 21, 2000 |
| Priority date | — |
| Expiry date | Jun 22, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to a method according to the eddy-current testing principle, and to a device for determining the thickness of an electrically conductive protective layer which is applied to an electrically conductive base material. The electrical conductivities of the protective layer and of the base material are different from each other. An excitation coil through which a high-frequency electric current is passed is brought near to the protective layer, so that an electric eddy current is produced in the protective layer and possibly in the underlying base material. A parameter related to the impedance of a probe coil is determined and is used as a basis for determining the thickness of the protective layer, for example by comparison with known reference values. The frequency of the high-frequency electric current is selected in such a way that the thickness of the protective layer is determined unambiguously for a ratio of the electrical conductivities of between 0.7 and 1.5.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.