A BRDF study on the visual appearance properties of titanium in the heating process. Issue 7 (16th April 2018)

• Record Type: Journal Article
• Authors: Liu, Yanlei; Yu, Kun; Li, Longfei; Zhao, Yuejin; Liu, Zilong; Liu, Yufang
• Is Part Of: Journal of modern optics. Volume 65:Issue 7(2018)
• Page Start: 888
• Page End: 898
• Publication Date: 2018-04-16
• Subjects: Spectral BRDF -- commercial pure Ti -- colour mechanism -- SEM -- XRD; Optics -- Periodicals; 535
• DOI: 10.1080/09500340.2017.1414892
• Languages: English
• ISSNs: 0950-0340

Abstract

Abstract: Bidirectional reflectance distribution function (BRDF) offers complete description of the spectral and spatial characteristics of opaque materials, i.e. the visual appearance properties of materials. In this letter, the visual appearance properties of titanium in the heating process are investigated by BRDF. The reliability of our results is verified by comparing the experimental data of polytetrafluoroethylene with the reference data. The in-plane spectral BRDF in visible region of heated commercial pure Ti at different incident and reflected zenith angles are measured. The experimental result indicates that the change tendency of BRDF vs. wavelength is not influenced by incident and reflected zenith angle, which implying that the colours of Ti may be pigment colouration rather than the structural colouration. Scanning electron microscopy (SEM) and the X-ray diffraction (XRD) testing are performed, and no titanium oxides are detected. The testing results imply that the colours may be generated by intermediate products during heated process. The powder samples are prepared, and the same colours as that of flake samples indirectly prove the validity of our conclusion. In addition, the spectral BRDF of optically smooth samples are measured, the results verify the reliability of our conclusion.