Meng Xuhui
Summary of content
It elaborates on the iron ornaments of gold, silver, carriages and horses excavated from the tombs of the Cultural Nobles of xirong culture in the Warring States of the Warring States collection of the Tianshui City Museum, and detects the disease through the analysis of scientific instruments in the early stage, and formulates a reasonable technical route, which is combined with traditional restoration to protect and restore the cultural relics. Thus, it can be seen that scientific analysis and detection instruments play an important role in the protection and restoration of cultural relics.
keyword
Paste gold and silver iron trim inspection analysis protection repair
The Iron Age is an extremely important era in the history of the development of human civilization. Natural iron on Earth is rare and exists in the form of oxides or other compounds. Therefore, the smelting of iron and the manufacture of iron tools have gone through a very long period. When people gradually mastered the technology of smelting iron on the basis of smelting bronze, the Iron Age came. At present, the oldest iron smelting tool unearthed in the world is a copper-handled iron-bladed dagger excavated from the tomb of the Hittite ancestors in northern Turkey (Anatolia), dating back to 4500 years ago (2500 BC). The oldest iron smelting tool found in China is two iron bars excavated from the Mogou Siwa Culture Tomb in Lintan County, Gansu Province, dating from between 3510 and 3310 years ago (1510 BC - 1310 BC).
In 2014, the Tianshui City Museum accepted a batch of cultural relics donated by private collectors, including a bag of rust-wrapped metal, and faintly saw decorative traces of gold and silver on the surface. Among them are round plaques, oval sub-waist ornaments, angled iron ornaments, square plaques and a pair of horse hammers.
Oval sub-waist plaque
Round plaque
Oval sub-waist iron plaque
Angled iron trim
Horsetails
Square plaque
X-ray flaw detection, XRD, XRF and asana microscopy were used to analyze and inspect the cultural relics to understand the rust composition, internal structure, external decoration, and complete damage of the cultural relics.
First, X-ray flaw detection analysis and detection:
Z11348
Z11358
Z11348 Sub-waist-shaped gold, silver and iron plaque ornaments, shown on the X-ray photographic film negatives, the entire artifact matrix is heavily corroded, and the middle and lower right are partially mineralized. The surface decoration of gold and silver sheet patterns is relatively complete, the lines are clear, and some parts are deformed and warped.
Z11358 folded gold and silver iron plaque decoration, through the X-ray photographic film negative shows that the entire artifact matrix is seriously corroded, and there is penetrating mineralization in the middle of the artifact hidden under the rust layer. Decorative gold and silver pieces are well preserved, the lines are clear, the parts are warped and deformed, and the surface is covered with hard knots.
Second, stereo microscopy observation
Analysis results: Using stereo microscopy, while the corrosion of the iron matrix changes, the surface of the gold and silver has also undergone deformation and cracking.
Fig. 1 Rolling up in silver (1:20)
Figure 2 Silver cracking (1:10)
Fig. 3 Rust hole in the iron matrix (1:12.5)
Fig. 4 Cracking and peeling of the gold layer, serrated edges (1:10)
Fig. 5 Rust of the iron matrix causes the gold layer to bulge and crack and deform (1:8)
Fig. 6 Stripping of the gold layer and rust holes and cracks in the iron matrix (1:8)
3. X-ray fluorescence spectroscopy
4. XRD analysis results
The sample corresponds to the XRD diffraction pattern and its corresponding peak data
1. Tieqi-1 XRD diffraction map
Conclusion: Figure 3.1 tieqi-1 - Eigen peak d value and phase fitted spectral lines
2. Tieqi-2, XRD diffraction map
Conclusion: Figure 3.2 tieqi-2 - eigen peak d value and phase-fitting spectral lines
According to the literature, since the Qin people moved west, they were in the middle of the Rong Di, and there were constant wars with Xi Rong, and the early Qin people were also destroyed by Xi Rong. It was not until Qin Mugong defeated Xi Rong that he secured his rear. According to the literature, after King Xiao of Zhou enfeoffed Bo Yi thirteen years later, Qin Feizi was a vassal and built the capital "Qin" land: in 688 BC, The Duke of Qin Wu won the victory of the Qin Wu Gong and set up Yi County in his territory, which was in the area of Li County, Qingshui, Zhangchuan, Zhuanglang, and Longxi Long County, which were around today's Shui. From the perspective of tomb forms and excavated relics, this cemetery has a strong local indigenous --- the factors and characteristics of Xirong culture, and combining various factors, we believe that this should be the cemetery of a certain rong leader under the rule of the Qin people, and the age of the tomb belongs to the late Warring States period. The excavation of the Majiayuan cemetery has provided new information for the study of the middle and late Warring States culture in eastern Gansu, and has important research value for the relationship between Qin culture and Xirong culture (1).
In order to protect cultural relics and reflect the value of cultural relics, according to the current status of cultural relics preservation and their own diseases, we have formulated a scientific protection and restoration plan, which was approved by the Provincial Cultural Relics Bureau and carried out protection and restoration work in 2017.
These cultural relics are a variety of metal coexistence, the surface is covered with thick cement, the chemical properties of iron are very active, through X-ray flaw detection we can clearly see that the matrix is seriously corroded, some parts have been mineralized, holes appear, very fragile. The chemical properties of gold are relatively stable, because gold is applied to the surface of iron, and while the iron matrix is rusted and deformed, the gold foil is also stretched and deformed, and some parts fall off with the rust, and some parts break. Silver foil oxidation is severe, similar to the situation of gold foil, the main diseases are oxidation, loss and deformation.
In view of these complex situations, a combination of chemical and mechanical methods is used to remove harmful and restore the original appearance of cultural relics.
1. Cultural relics cleaning. First soak with deionized water, the water temperature is maintained at 80 ° C, replace the deionized water regularly, and detect the presence of chloride-free ions with silver nitrate.
2. Mechanical removal of surface cement. Brush out the floating soil and rust on the surface with soft hair. With the help of knives, drills, chisels, hammers, needles and dental tools, carefully remove fluffy rust from the surface with appropriate tools.
3. Chemical methods to remove rust. For rust layers with high hardness, chemical patches are used to soften and remove, and repeated operations are used to rinse off the remaining chemicals on the utensils with deionized water. Ph.D. test strips check pH.
4. Reply to gold and silver foil. For the back-up of the deformed gold and silver foil, the bonding material is B72.
5. Corrosion inhibition. Apply and seal the iron matrix brush with a configured tannic acid solution, generally brushing 2-3 times.
6. Completion. The defective parts are completed with synthetic resin mud and colored, which is consistent with the hue of the utensils.
7. Sealing. Use a certain proportion of B72 to brush the surface of the iron matrix to coat and seal.
Mechanical removal of surface incorruptibles
Chemical patching softens surface induration
Wash, soak, desalinate
On the basis of fully investigating the existing historical data and preservation status of gold and silver iron ware in the collection of Tianshui City Museum, through the analysis and detection of cultural relics diseases and information with the help of modern scientific analysis instruments, and for the preservation status, sample analysis and etiological analysis results of these iron cultural relics, with reference to relevant materials, scientific and reasonable protection and restoration technical routes are formulated. According to the basic principles of cultural relics protection, the iron is pre-reinforced, cleaned, desalinated, corrosion inhibited, sealed and other steps. After the protection and restoration of cultural relics, diseases can be effectively controlled or eliminated; the historical information and artistic value of cultural relics are revealed; and cultural relics can meet the needs of daily storage, display and research of museums.
(1) "Briefing on the Excavation of the Warring States Cemetery in Majiayuan, Zhangjiachuan Hui Autonomous County, Gansu Province in 2006", Cultural Relics, No. 9, 2008.
Originally published in: China National Expo, No. 14, 2021.