Analyses of the materials and techniques used in the “Tian Di Chang Chun” horizontal plaque inscribed by the patriotic general Feng Yü-hsiang

Abstract The “Tian Di Chang Chun” horizontal plaque inscribed by the general Feng Yü-hsiang in R.O.C. 25 (1936) shows his patriotic, compassionate, fair, and just thoughts and ideals. It has significant educational value for contemporary society. However, due to the aging of the materials and some factors in the preservation environment, the coloured decorative coating on the surface of the plaque has shed. The digital microscope system, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD) and micro-Fourier transform infrared spectroscopy (µ-FTIR) were used to analyse the materials and techniques used on this plaque. It has been showed that the decorative layer of the plaque consists of a red Chinese lacquer film layer on the surface and a ground layer. The red lacquer film layer comprises Chinese lacquer, tung oil, and cinnabar. The materials used for the ground layer are the blood putty made of the blood product, youman (flour-oil-lime mixture), and brick powder. The technique used is the SDH (San Dao Hui) layer technique in ancient buildings. This study provides physical evidences regarding the materials and techniques used in inscribed plaque relics, and also provides technical supports to further protect and restore the plaque.