PURPOSE: To enable the measuring of a thickness at an arbitrary point on an applied surface of a lining film without breaking it by detecting a signal magnetic field generated with a scanning on the lining film by a magnetic sensor to determine a correlation between the resulting output voltage and a magnetic permeability attributed to soft magnetic particles contained in the thickness of the lining film.
CONSTITUTION: A surfactant is added to a paint agent to disperse soft magnetic particles therein evenly so that the soft magnetic particles in a lining film 3 are contained uniformly to form the lining film 3 with the paint agent applied on the ground 4. In the measuring of the thickness of the film, a magnetic sensor 8 having a couple of an exciting coil 1 and a sensor coil 5 feeds an alternating current to the exciting coil 1 to detect changes in mutual inductance due to the effect of magnetization of the soft magnetic particles in the lining film 3. The soft magnetic particles are ferrite with the average size of 10μm or less and contained at a rate of 0.1-5vol.% over the entire area of a painted film.
TAKEUCHI YOSHIAKI
YAMAUCHI FUMIO
YAMASHIRO IKUTAMI
SHOEI YAKUHIN KK
NEC ENVIRONMENT ENG LTD
FUETSUKU KK J
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