Abstract
THz wave has been receiving increasing attention in many engineering applications because of the following characteristics. THz wave penetrates many kinds of materials except for metals and water. Materials have their own fingerprint absorption spectrum. THz wave is safe for human body. The transmission property of THz wave enables us to develop an inspection technique for the substrate material under coating. In this paper, a nondestructive evaluation technique based on THz wave imaging is developed for coating materials. We have evaluated transmittance of iron(III) oxide (Fe_2O_3) and carried out THz imaging for paint coated steel plate using Terahertz time-domain spectroscopy (THz-TDS) system, to investigate the feasibility of proposed nondestructive evaluation technique.
