| 摘要 |
PROBLEM TO BE SOLVED: To precisely correct a deviation from an initial state of a film thickness, measured value caused by changes with time of an apparatus condition, when online-measuring a film thickness of a chemical conversion coating using a long-wavelength type infrared film thickness meter.SOLUTION: In this film thickness measuring method of a coating, stainless steel plate having a mechanically roughed surface with surface roughness adjusted so that the Ra ratio defined in the following equation (1) is 0.7 to 4.0 is used as a calibration plate. Ra ratio=Ra [base material]/Ra [calibration plate] (1), where Ra [base material] is an arithmetic mean roughness Ra (μm) of the base material (without coating), and Ra [calibration plate] is an arithmetic mean roughness Ra (μm) of calibration plate. |
