Abstract:Epoxy resin is a widely utilized replacement material for the mural support layers, and its aging degradation can significantly affect both the stability and aesthetics of murals. To further investigate the aging characteristics and mechanisms of epoxy resin, and to clarify the detrimental effects of its aging process on murals, this study employed E44 bisphenol A epoxy resin along with mural plaster materials as laboratory aging samples. Additionally, natural aging samples were selected from the murals of Fengguo Temple and the tomb of Shi Shewu. Comprehensive analyses, including mass and volume measurement, mechanical performance evaluation, scanning electron microscopy (SEM), and Fourier transform infrared spectrometry (FTIR), were conducted to examine changes in the physical properties and chemical structures of the samples during aging. The findings indicate that under conditions primarily influenced by temperature and humidity, epoxy resin exhibited increased yellowing, reduced gloss, and decreased density. Furthermore, characteristic peaks associated with functional groups such as epoxide groups, hydroxyl groups, ether bonds, and benzene rings within the polymer chain were observed to weaken significantly or disappear over time. These observable changes may serve as quantitative indicators for assessing epoxy resin aging.  In the initial stages of aging, moisture absorption led to swelling in the epoxy resin sample due to interactions with its substrate. This resulted in internal stress imbalances that generated micro-cracks. As aging progressed, these micro-cracks continued to proliferate—deepening and expanding under the influence of water molecule—ultimately resulting in extensive voids that markedly reduced both the mechanical strength and adhesion capacity of the material. Thermal exposure induced free-radical chain reactions within the epoxy resin, compromising their molecular structure and consequently affecting internal cohesion alongside weather resistance. Thus it can be concluded that epoxy resin predominantly contributed to a decline or failure in adhesive strength over time. Epoxy resin primarily contributes to the deterioration of murals by compromising adhesion and support strength, which may result in weakening or loss of bond strength. Additionally, it inflicts damage on the mural itself due to the stress exerted at the interface between the plaster layer and epoxy resin composite materials. Consequently, this process leads to issues such as cracking, detachment, deep loss, and eventual loss of the mural.

Abstract:Situated in Sichuan Province, China, the Anyue Grottoes are renowned for their abundant cave art and feature a significant quantity of Buddhist rock art carvings. One notable example is the stone carving figures from Piludong Stone Carving, considered as a high-quality example of Song Dynasty grotto statues due to their more comprehensive overall preservation. The statues exhibit a sophisticated fusion of creative production and religious ideas, with their elegant modeling and passionate expressions. Furthermore, the naturalism and harmonic beauty that characterized this era’s creative movement give these sculptures historical significance in addition to their religious significance. However, rainfall, groundwater, temperature, humidity, and other natural elements have caused the statues to suffer from delamination, detachment, powdering, and other weather-related ailments that affected the statues’ long-term preservation and display. The dominant factors responsible for forming typical diseases of Piludong Stone Carving were comprehensively concluded through the analysis of monitoring data on rainfall, groundwater, temperature, and humidity in the microenvironment, as well as water content on the surface of the statues, and by analyzing samples of typical delamination and detachment. The environmental data of the statues and their surroundings were gathered and thoroughly analyzed in this study, and the findings could serve as a guide for bolstering the scientific conservation of numerous monuments in Sichuan. Microenvironmental monitoring revealed that the water contents of the statue surface and bedrock, as well as capillary water and groundwater, were all highly susceptible to abrupt changes during rainfall. According to the monitoring data, the groundwater level rose 10-15 hours after the end of heavy rainfall; the statue surface layers at four heights—50,100, 150 and 200 cm—became oversaturated within 0.5-3 hours; and the environment surrounding the statues experienced a short-term increase in humidity. Temperature fluctuations on the statue surface were greater than in the surrounding environment. The maximum annual temperature difference of the statue surface was 45.9℃ and that of the surrounding environment was 36.6℃, a difference of 25%. Infrared thermal imaging monitoring revealed that during periods of ambient temperature increase, the delamination area surface temperature was higher than that of the surrounding area, with localized high-temperature zones. During the daytime, the temperature of delamination or detachment areas consistently exceeded that of the surrounding area, and the temperature distribution gradient was more pronounced in the delamination areas. The calcareous cementation of the bedrock of Piludong Stone Carving was demonstrated by testing and analysis using ion chromatography (ICS), X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS). The bedrock contained a higher content of feldspar type, and the clay minerals in the weathered samples had higher concentrations of mica. The predominant clay minerals included chlorite and illite, along with mixed layers of chlorite and montmorillonite. Soluble salts in the clay minerals were significantly enriched along the gradient of lamellar exfoliation areas, dominated by CaSO₄·nH₂O, which filled and blocked water vapor channels. A synthesis of the fit analysis linking environmental changes with soluble salt migration and soluble salt mitigation and phase transitions indicated that precipitation plays a significant role in short-term and rapid changes in the water vapor environment of Piludong Stone Carving, Anyue. For instance, prolonged periods of heavy rain can cause significant short-term variations in statue surface water content, the nearby groundwater table, and the humidity levels of the surrounding area and niche. The rate and amplitude of temperature and humidity changes on the statue surface differ significantly from those in the surrounding environment, and variations are also notable in surface temperature and humidity between various sections of the same statue niche. On the statue surface, temperature and humidity are correlated. Daily humidity variation shows a relatively stable period at night (approximately 00:00-5:00), a sharp decline in the morning section (approximately 6∶00-13∶00), a low-humidity period in the afternoon (approximately 14∶00-17∶00), and a rising trend in the evening (approximately 18∶00-23∶00). In addition, soluble salt transport is driven by changes in ambient water, resulting in pronounced soluble salt gradient distributions in the surface layers of the bedrock. During frequent water vapor transformations, poorly soluble CaSO₄ precipitates and becomes enriched in the surface layer of the rock. The formation of soluble salt-rich zones in the bedrock surface layer blocked water vapor channels within the bedrock. The microenvironmental changes surrounding the artifact area corresponded with the conditions that favor Na₂SO₄ phase transition. The expansion forces generated by the repeated dissolution and crystallization of Na₂SO₄ continuously act on mineral particles and cementation, destroying the microstructure of the statue bedrock and causing the powdering and detachment on the statue at the macroscopic scale. Weathered debris also accumulates in areas of flake exfoliation. The primary cause of the powdering and detachment of the rock carvings is the coupling effect of soluble salts and microenvironmental changes.

Abstract:The stone carvings in the mausoleums of the Six Dynasties (hereinafter referred to as “Six Dynasties stone carvings”) in the Jiangsu region have been exposed to natural weathering environment for more than one thousand years and have suffered severe deterioration. The Six Dynasties stone carvings are primarily made of limestone, with calcium carbonate as the main component, which makes them highly vulnerable to acid rain corrosion. In addition, their high porosity allows external water and harmful substances—such as acid gas, dust and biological agents—to easily penetrate the stone. Ultrasonic wave velocity testing revealed that most of the Six Dynasties stone carvings exhibited varying degrees of weathering, indicating an urgent need for scientific conservation. A wide variety of surface sealing materials has been developed for the conservation of stone cultural heritage. In this study, artificial aging tests were conducted on limestone samples under simulated natural environmental conditions. During the aging cycle, the samples were periodically tested and analyzed to evaluate their performance and ultimately identify the surface sealing materials with the most effective protective properties.

Abstract:The piece-mould casting technique was a quintessential component of the ancient Chinese bronze smelting and casting industry, and is unique among ancient cultures worldwide. Scholars normally consider levigated loess to be the primary raw material used for mould production. In recent years, with the increasing application of microscopic analytical techniques, the use of loess alone can no longer fully characterize piece-mould casting technique. A considerable number of studies have found that the mould raw materials could include alluvial soil, weathered soil, and other types of soil. There were also some moulds made from loess that had not been thoroughly levigated. The workshop areas at Xincun, Hebi, Henan and Yaoheyuan, Pengyang, Ningxia are two important sites excavated in recent years, where abundant smelting and casting remains have been unearthed. This study, through the combination of petrographic analysis and scanning electron microscopy, identifies remains whose raw materials consist of un-levigated loess. The results indicate the presence of substantial clay aggregates in some moulds and cores, suggesting that the materials either directly taken from the soil or made by mixing various soils without levigation. Some dried or sintered raw materials were used to make moulds, demonstrating that dry and wet raw materials could also be effectively combined. Layered mould-making and coating techniques were selectively applied and omitted in areas with low surface gloss requirements. This technical simplification, potentially a byproduct of specialized bronze-casting division, exhibits a degree of persistence across both geography and time; therefore, it might represent a mechanism by which the Zhou royal family controlled the bronze-casting technique.

Abstract:In 2020-2021, the large-scale timber-framed building F63 of the Qujialing culture was excavated at the Jijiaocheng site. This building is magnificent in scale, with a well preserved foundation and distinctive construction craftsmanship, and it holds significant importance in the history of Chinese architecture. A total of 109 wood samples were collected from F63 and from the surrounding relevant settlement context. Thin sections were made using freehand sectioning. Then, the microscopic structures of the samples were observed under an optical microscope. Finally, tree species were identified through comparison with relevant reference materials. The results show that the timber used for F63 was primarily derived from Machilus spp., Phoebe spp. and Cinnamomum spp. However, the samples collected from the surrounding non-timber-framed buildings exhibited a greater diversity of wood species, which were not commonly used for structural timber components. These findings indicate that tree species appropriate for timber-framed construction were scarce in the immediate vicinity of the site, and that the timber used for building F63 was likely not sourced locally. As indicated by the results, the building materials used for F63 were relatively uniform. The selected timber had a fine and homogeneous structure, moderate mechanical strength, favorable material properties and a certain degree of corrosion resistance, reflecting the relatively high level of material selection practiced by the inhabitants of Jijiaocheng. The overall area of F63 is approximately 630 m². According to the inferences made by relevant scholars, the main building was about 5.5 m in height, while the corridor reached approximately 4 m. The construction of a building of this scale would have required a substantial quantity of timber. The timber used for the construction of F63 might have originated from the nearby mountainous areas. According to relevant studies, the Liyang Plain is part of the Dongting Lake Plain. In prehistoric times, the area of Dongting Lake was vast and the water level of rivers was much higher than it is now. Part of F63 was built on top of moats, further indicating that a well-developed water system existed at the site during that period. The inhabitants of Jijiaocheng had already mastered comprehensive planning ability of the water system and possessed a complete irrigation system. They practiced paddy cultivation on a large scale, as evidenced by the large amount of rice chaff unearthed at the site. The area around Jijiaocheng was mainly irrigated farmland area with a managed vegetation landscape at that time, making it unlikely that extensive forest resources were available near the house sites. The terrain of Lixian County is higher in the northwest, with abundant vegetation, a well-developed water system and convenient water transportation. Therefore, it is highly likely that the timber used for F63 building was sourced from the nearby mountain forests and transported to the Jijiaocheng settlement via the Cen River and its tributaries. The construction of F63 required substantial manpower and material resources from the inhabitants of Jijiaocheng. Under the social conditions of that time, such an undertaking could not have been an individual act, but rather embodied the collective will of the entire settlement. The construction of F63 not only had the significance of residence function but also carried a higher spiritual connotation. From the acquisition, transportation and processing of raw materials to architectural design, construction and use, all of these aspects were manifestations of public power. This indicated that the settlement had a relatively large population, a well-developed social organization, and strong capacities for management and coordination. The comprehensive study of F63 provides important information for understanding settlement organization, social relationships and the level of social productivity at that time.

Abstract:Dehua kiln was a famous folk kiln in Southern China with a long history. The surfaces of Dehua white porcelain unearthed from the kiln site are generally attached with yellow induration. Based on a comprehensive analysis of a Southern Song white porcelain sample with yellow induration, this study investigated the deterioration mechanism of the glaze and the formation of induration deposits in the soil environment of Dehua. The analytical methods used include optical microscopy (OM), energy dispersive X-ray fluorescence (EDXRF) spectrometry, micro-Raman (μ-Raman) spectrometry and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS). The results indicate that the Southern Song Dehua glaze is a transparent calcium-alkali glaze. The main degradation processes in an acidic soil environment include ion exchange and network dissolution. Silicon released during network dissolution subsequently condensed to form silica gel on the glaze surface, and variations in local pH led to the development of two special microstructures of silica gel. The yellow induration layer was formed through the condensation of silica gel and inorganic soil colloids via electrostatic attraction and intermolecular force.

Abstract:The early Dawenkou culture (6200-5600 a BP) played a pivotal role in the formation of agricultural civilization in ancient Northern China, and advances in dry farming and livestock raising provided a significant foundation for social expansion and development during this period. However, our knowledge of livestock-raising strategies during the early Dawenkou culture still remains limited. To address this gap, stable carbon and nitrogen isotopic analysis of bone collagen from dogs (Canis familiaris), pigs (Sus scrofa domesticus) and deer (Cervidae) of the early Dawenkou culture recovered from the 2018 excavations at the Helou site in Dingtao, Shandong Province, was conducted to investigate animal diets, with a particular focus on domestic animal management and raising practices. The results imply that the mammals at the site probably had access to a variety of food sources. Cervid animals (n=7) exhibited the most negative δ¹³C value (-19.7±2.0)‰, indicating a C₃ plant-based diet. The δ¹³C and δ¹⁵N results of the two individual dogs (-17.2‰ and 9.1‰, -10.9‰ and 7.7‰, respectively) exhibited various proportions of C₄ plants in their diets as carnivores, suggesting that their food had undergone varied levels of human involvement in their feeding. As for pigs (n=31), the δ¹³C values ranged from -20.6‰ to -9.8‰. Although the overall diet was dominated by C₃ plants [δ¹³C =(-18.2±1.6)‰, n=30], almost half of the samples showed a mixed C₃/C₄ diet pattern, with a comparatively smaller contribution from C₄ food than C₃ plants. Furthermore, one piglet, estimated to be 4-6 months old, appeared to have fed primarily on C₄ food resources. A zooarchaeological study has also previously been carried out at this site. Through analysis of the proportion of NISPs and MNIs among the faunal remains of different species, together with evidence from pig skeletal morphology, age-at-death profiles and measurements of mandibular M₃, the study indicated the presence of domestic pig raising and management during this period. Based on information regarding pig age groups, a potential correlation between the carbon and nitrogen isotope ratios and pig age was observed; additional data are required to substantiate this hypothesis. A thorough examination of animal remains and relevant literature was conducted, along with a comparison of the stable carbon and nitrogen isotope ratios from human and animal bones at the Dawenkou and Beiqian sites in Shandong Province. This analysis led to the hypothesis that domestic pig raising and management practices of domestic pigs during the Helou site period most likely involved a combination of free-range and captive breeding methods. Such practices may, to some extent, reflect local traits of raising and management of domestic pigs in the hilly areas of the Lower Huang-Huai Basin, where these early Dawenkou cultural sites are located. On the other hand, a millet-based dry farming system had largely been established in the traditional Central Plains during the Miaodigou period (6000-5500 a BP). Data from the Wayaogou, Dongling, and Xipo sites demonstrated that domestic pig raising mainly relied on by-products from local millet cultivation. According to archaeobotanical studies, agricultural development and production capability in the area surrounding the Helou site were delayed and lower than those in the Central Plains during the same period. Therefore, this study suggests that livestock raising at Helou also showed a lower degree of dependence on local crop cultivation. Instead, people likely adopted an extensive husbandry strategy characterized by small-scale livestock raising to obtain some meat resources while maximizing the use of the local natural environment, including plant and animal resources, and minimizing the costs of raising domesticated animals, thereby achieving a balance between human-land relations.

Abstract:To gain deeper insight into prehistoric pottery manufacturing techniques, phytolith analysis was applied to plant-tempered pottery excavated from the Sunjiacheng site (5800-4300 BP). Sand-tempered pottery and fine-clay pottery unearthed from the same context were used as comparative references. The research findings reveal significant differences in raw material selection and production techniques between plant-tempered pottery and both sand-tempered and clay pottery. Notably, the legs of plant-tempered pottery tripod Ding vessels exhibited distinct raw material composition and production techniques compared to other vessel parts. Further analysis revealed that plant admixtures, primarily rice husks, were incorporated into pottery production during the early phase of the early Sunjiacheng period. The use of plant temper reached its peak from the late phase of the early Sunjiacheng period to the early phase of the middle Sunjiacheng period, after which it gradually declined and was ultimately completely replaced by sand-tempered pottery during the Xuejiagang cultural period. These findings not only enhance our understanding of raw materials and technological choices in prehistoric pottery production, but also highlight the unique advantages and profound significance of archaeobotanical methods in the field of pottery analysis.

Abstract:Ancient lighting fuels included animal fat, vegetable oil and wax, which could be used individually or combined. Early lighting fuels were mainly animal fat and wax, and the costs were high. With the emergence of plant-based fuels, lamps and lanterns became more widely accessible. This study conducted a scientific analysis of the surface residues of a pottery lamp unearthed from Tang Dynasty tombs in Sijiqing, Beijing. Through the study, the main substances of the residues of the pottery lamp were identified, and the relevant information of the lighting fuel in the pottery lamp was clarified. These findings contribute to the understanding of the development level of the handicraft industry in the Tang Dynasty and the ways in which natural resources were developed and utilized by the ancient inhabitants. In this study, pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) and gas chromatography-mass spectrometry (GC-MS) were applied to the analysis of residues from a pottery lamp unearthed from the Tang Dynasty tombs in Sijiqing, Beijing. 1) Py-GC/MS was used to analyze the residue samples, and polycyclic aromatic hydrocarbons such as naphthalene, fluorene and anthracene were detected. These chemicals were produced by incomplete combustion of organic matters and are therefore speculated to be related to the combustion of fuel in the lamp. A small amount of nitrogen-containing substances such as 1-methyl-1H-pyrrole were also detected in the samples. These substances are associated with animal-derived materials, indicating that the pottery had been exposed to protein substances, and suggesting that the pottery lamp had other uses before being used as a lamp. 2) Lipids were extracted by the direct acidification methanol extraction method, and the lipids in the samples were analyzed by GC-MS. Glycerol, fatty acids, β-sitosterol and other substances were detected. Based on the ratio of palmitic acid to stearic acid (P/S), it was inferred that the fuel contained vegetable oil. In addition, unsaturated fatty acids such as palmitoleic acid, linoleic acid, oleic acid and erucic acid were also detected. Erucic acid is mainly found in cruciferous plants, indicating that the pottery lamp contained cruciferous vegetable oil. The two methods, Py-GC/MS and GC-MS, complement each other and provide more comprehensive information on unknown organic residues. The study of the main components of crust residues on the surface of the pottery lamp excavated from the Tang Dynasty tombs in Sijiqing has clarified that the lighting fuel used was cruciferous vegetable oil, which contributes to understanding the use of vegetable oil as a lighting fuel in the Tang Dynasty.

Abstract:As an indispensable item in ancient Chinese funeral ceremony, quilts served as an important medium for cultural inheritance and emotional expression. Two quilts unearthed from the tomb of the Tuyuhun king Murong Zhi in Wuwei, Gansu Province. One is a leno (Luo) quilt striped with brown and ochre stripes, and the other is a damask (Qi) quilt striped in yellow and deep red. Due to the long-term underground burial, both quilts suffered from severe deterioration. Scanning electron microscopy-energy disperse spectrometry (SEM-EDS), Fourier transform infrared spectrometry (FTIR), ultra depth-of-field microscopy and ultra high-performance liquid chromatography-mass spectrometry (HPLC-MS) were used to conduct analysis and detection on the fiber materials, aging characteristics, pollutants and dye components. The results indicate that the quilts were made of mulberry silk and incorporated several wave structures, including leno, damask and plain weave. The detected pollutants mainly contained calcium phosphate precipitates and inorganic mineral particles. The identified dyes included madder, indigo and Phellodendron. Based on the scientific analysis, appropriate conservation and restoration measures were developed. Silk protein reinforcement technology was applied to reinforce the quilts overall, combined with backing and needlework, and missing parts were restored. After the restoration, the damages were effectively controlled, and the quilts’ historical appearances were largely recovered, providing a physical basis for the further research.

Abstract:Completing missing portions of ancient Chinese texts is a critical task in textual research and cultural heritage preservation. This study proposes a pretraining model based on the fusion of phonetic and character shape features to improve the accuracy of ancient text completion. The proposed method decomposes the shape and pronunciation of Chinese characters to generate sub-character structures and integrates this information through a cross-attention mechanism, thereby enhancing the model’s semantic understanding of ancient texts. The methodology involves modelling Chinese characters using Wubi input codes and phonetic systems, encoding each character as a short sequence, and constructing a vocabulary through a sub-word segmentation algorithm. Experimental results show that the proposed method achieves a completion accuracy of 70.02% on the transmitted literature dataset and 63.76% on the unearthed literature dataset, demonstrating its effectiveness for the intelligent completion of ancient texts.

Abstract:This study utilizes 3D scanning point cloud data of the Qin Terracotta Warriors to establish solid models of vertical arms and weapon-holding bent-elbow arms using COMSOL software. Stress distribution in shoulder joints and stress concentration phenomena induced by existing cracks are analyzed to investigate the performance requirements of adhesive materials used in repairing shoulder cracks of the Terracotta Warriors. For vertical-arm figures, stress is primarily concentrated at the lower edge of the shoulder joints. When cracks exist in this area, abrupt stress variations exceeding the material strength limits may occur locally. Adhesive repair can optimize the surrounding stress distribution, reducing both maximum stress values and stress gradients to safe ranges. Using epoxy resin as the bonding material, a comparative parameter analysis of lower-edge cracks in vertical-arm shoulders and armor cracks in bent-elbow arms reveals that adhesives with a lower Young’s modulus and thicker bonding layers can effectively reduce maximum stress values at repair sites to safe levels, while the contribution of Poisson’s ratio variations is relatively minor. In practical restoration, appropriate bonding materials should be selected based on stress characteristics of specific repair locations to reduce Von Mises stress near joints, thereby decreasing stress intensity factors and mitigating secondary damage risks. This research provides valuable references for the preventive conservation and restoration of cultural relics.

Abstract:To address challenges in mural outline generation, including inadequate feature extraction, poor capture of edge details, and limited robustness, this study proposes an efficient method for accurately extraction outlines from mural images with complex textures and details. A new framework based on the Holistically-Nested Edge Detection (HED) model is developed innovatively by integrating a Scale Enhancement Module (SEM) and a Compressed Spatial Attention Module (CSAM). The SEM utilizes dilated convolutions to achieve multi-scale feature extraction, enabling enhanced capture of both local and global information and improving outline extraction accuracy. The CSAM module focuses on refined representation of local edge features, effectively reducing information loss during feature propagation. Additionally, a loss function based on the Dice coefficient is introduced to address class imbalance between edge and non-edge pixels, further improving edge detection performance. Quantitative and qualitative results demonstrate that the proposed method clearly outperforms in handling texture blur and local information loss, thereby has advantage in mural outline generation. It successfully improves the outcome of mural outline generation and validates the effectiveness of multi-scale feature fusion and spatial attention mechanisms in complex texture image processing. The proposed approach provides new insights and directions for the digital conservation and restoration of murals.

Abstract:The Yangtze River Estuary No.2 is one of the most important shipwreck discoveries in China. The large quantity of unearthed porcelains provides key material evidence for the study of maritime trade during the Qing Dynasty. In this study, 33 porcelain samples of various types including blue-and-white, famille-rose and celadon porcelains, as well as three intact wares from the Yangtze River Estuary No.2 shipwreck, were examined. Non-destructive X-ray fluorescence (XRF) spectrometry and microscopy were used to conduct a preliminary research on their chemical compositional characteristics, provenances and corrosion conditions. The results show that most of the blue-and-white, famille-rose and celadon porcelains were likely produced within the Jingdezhen kiln system, and some originated from kilns in Zhejiang and Fujian. These findings reflect the extensive riverine and maritime porcelain trade networks of the Qing Dynasty. Although the porcelains were produced in folk kilns, they feature exquisite craftsmanship and high material quality. This study provides a scientific basis for the classification, conservation, display and further research on porcelain relics from shipwreck contexts.

Abstract:The Palace Museum houses seven Qing Dynasty copper statues of immortals, six of which are covered with an unusual black substance rarely observed on the surface of copper artifacts. In this study, a statue of an immortal holding a Yuanbao and riding a Qilin was selected as the research object. The black substance on its surface was analyzed using a range of analytical techniques. The results indicate that the black substance is a mixture of carbon black, natural waxes (insect wax and beeswax) and natural resins (shellac and rosin), suggesting that it represents an intentionally applied decorative and protective surface layer. Based on the historical use and physicochemical properties of these four natural substances, it is proposed that shellac and rosin functioned as adhesive components, beeswax represented the molding material from the lost-wax casting process remaining on the artifact surface, and insect wax was applied to enhance the luster of the black layer. In addition, the preservation status of the artifacts was evaluated, the causes of localized corrosion were analyzed, and corresponding suggestions for the preventive conservation of similar artifacts are proposed.

Abstract:To investigate the preservation condition and manufacturing techniques of Qing Dynasty iron paintings in the collection of Anhui Museum, a series of scientific analyses were conducted using X-ray fluorescence spectrometry (XRF), metallographic microscopy, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), and X-ray diffraction (XRD). The results indicate that the cast iron paintings were assembled using tin soldering and zinc may have been applied to the surface. Among the six selected iron paintings examined, four were identified as decarburized cast iron products (including decarburized cast iron and wrought iron), while the remaining two were wrought iron and carburized wrought iron, respectively. All of the iron paintings were produced through forging techniques. Analysis of corrosion products revealed the presence of β-FeOOH, a harmful form of rust, within the corrosion layers. The black-brown substance exfoliated from the iron painting surface was identified as varnish, and the backing paper was likely coated with an adhesive glue layer.

Abstract:There are few reports on the occurrence of formate salts in the patina of brass buckles from clothing on a large-scale. Scientific methods, including super depth-of-field microscopy (DM), portable X-ray fluorescence spectrometry (pXRF), laser Raman spectrometry (Raman), and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) were employed to characterize the brass buckles and their patina from seven Qing Dynasty clothes. The results indicate that the buckles were precisely cast brass alloy, some of which were glided. The corrosion products were primarily composed of formate salts, including known compounds such as sodium copper formate [Cu₄Na₄O(HCOO)₈(OH)₂·4(H₂O)], dicoppertrihydeoxyformate [Cu₂(OH)₃HCOO], Zinc C [Zn₄Cu₃(Zn1-xCux)₆(HCOO)₈(OH)₁₈·6(H₂O)], as well as unidentified formic acid corrosion products containing Cl and S. The formation of these formate salts is related to the casting process of the brass buckles, the integrity of the gilding layer, and the storage environment. These corrosion products not only compromise the overall appearance of brass buckles, but also contaminate adjacent textiles and pronounced corrosive propagation. Therefore, the buckles need immediate corrosion removal, followed by wrapped with acid-free paper. This scientific analysis provides a theoretical basis for the development of conservation and restoration strategies for brass buckles on clothing, and serves as a reference for the study of similar cultural relics.