| 摘要 |
PROBLEM TO BE SOLVED: To improve the fluidity of the colored magnetic particle, to uniformly diffuse the magnetic particle over the work surface to be inspected, and to easily remove the colored magnetic particle other than the magnetic particle indication by mixing the hydrophobic inorganic powder into the colored magnetic particle to uniformly diffuse the hydrophobic inorganic powder into colored magnetic particles. SOLUTION: Pure iron powder of 85 pts., by weight, of 20μm in grain size, Lumogen- yellow of 5 pts., polyterpene of 8 pts., and acetone of 2 pts. are sufficiently kneaded and dried and pulverized to obtain the fluorescent colored magnetic particle of 23μm in grain size. Alumina of 67 pts., silane coupling agent of 3 pts., and trichloroethylene of 30 pts., are sufficiently mixed, and dried for 20 minutes at 150 deg.C, and pulverized to obtain the hydrophobic alumina powder. The hydrophobic alumina powder of 3 pts. is mixed in the fluorescent colored magnetic particle of 100 pts., for 15 minutes by a V-type mixer to obtain the dry fluorecent magnetic particle. The particle is diffused into the air by a magnetic particle sprayer, and sprayed on the surface of a magnetized work to be inspected, and the work is lightly oscillated to clearly obtain the yellowish green magnetic particle indication with excellent contrast at a defective part of the surface of the work under the black light (ultraviolet ray).
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