| 摘要 |
PCT No. PCT/FI83/00023 Sec. 371 Date Nov. 3, 1983 Sec. 102(e) Date Nov. 3, 1983 PCT Filed Mar. 14, 1983 PCT Pub. No. WO83/03303 PCT Pub. Date Sep. 29, 1983.The characteristics of various solid materials, in particular, surfaces of and coatings on metals and thickness of surface hardening layers are measured without damaging the specimen. The phase angle of a continuous thermal surface wave produced by a modulated light beam is measured. The phase angle of the continuous thermal wave progressing along the surface of the specimen is measured by temperature detectors either at a fixed distance from the light spot, as a function of frequency, or at a fixed frequency, as a function of distance. The phase angle of the thermal wave depends upon the thickness of the surface hardened layer whereby such thickness is measured.
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