Figure 5 - available from: Scientific Reports
This content is subject to copyright. Terms and conditions apply.
Spatial distribution of Cr-rich weapons. Distribution map of the triggers, ferrules and arrow bundles excavated in the easternmost trenches of Pit 1, noting those analysed by pXRF and highlighting the samples found to contain chromium.
Source publication
For forty years, there has been a widely held belief that over 2,000 years ago the Chinese Qin developed an advanced chromate conversion coating technology (CCC) to prevent metal corrosion. This belief was based on the detection of chromium traces on the surface of bronze weapons buried with the Chinese Terracotta Army, and the same weapons’ very g...
Context in source publication
Context 1
... and/or the output of specific workshop units [15][16][17] . Given the uneven presence/absence of chromium on the weapons, we hypothesised that only certain weapon batches, perhaps those made in a particular workshop, had been treated with chromium. However, spatial analysis shows that the distribution of chromium-bearing weapons is largely random (Fig. 5) and it does not correlate with the distribution of the weapon production batches identified previously [15][16][17] . This evidence suggests that the chromium presence is not the result of deliberate action. Furthermore, as discussed below, there is no correlation between chromium presence and a given weapon's state of preservation, ...
Similar publications
Topical monotherapy of nail infection is limited by poor drug permeability into the human nail plate. Numerous substances and methods are applied to improve the antifungal agent delivery across the nail plate. This work aimed to evaluate the effect of chemical and physical enhancers on the accumulation and permeation of amorolfine hydrochloride thr...
Furniture industry is one of the oldest and a developed industry in Turkey. In the last 20-25 years of furniture industry, in addition to production for the country's need, Turkey started to produce for export, to work technology-supported and to make large scale mass production rather than local workplace production. In addition to that, investmen...
The paper reports on the results of a comparative study of the adhesive strength of coatings made of unfilled epoxy lacquer and lacquers filled with nanosized TiO 2 , SiO 2 , and ZnO oxides, which have been obtained in scratch testing experiments. The coatings are applied onto an aluminum-magnesium alloy base. The value of specific elastic energy p...
Golf tees with a plastic head and wooden shaft were prepared by back injection moulding of a beech wood (Fagus sylvatica) shaft with different polymers (i.e. ionomer, polypropylene, and polyamide). In order to facilitate adhesion between the polymer melt and the wood surface, the wooden shafts were pre-treated with different primer substances, incl...
Citations
... There are many similarities in elemental composition, particularly in terms of major elements (aluminium, calcium, and iron), as well as sodium and magnesium. Without excluding the effect of environmental factors related to the burial environment [19], the samples selected for the experiment have relatively Fig. 2 a, b and c the inscriptions on the surface of the sample, d, e and f the impressions of the bamboo slips, g, h and i the seal marks of rope strips consistent elemental composition [20]. Within the PCA analysis, the cumulative contribution rates of the first three principal components are 43.045%, ...
Clay sealing represents the key physical example of the document sealing system of the Qin dynasty in ancient China. However, only the inscriptions and aesthetic values of clay sealings have been discussed until now, and the relevant sources have not been traced from the perspective of scientific analysis. A total of 81 clay sealings unearthed in Xi’an were studied via ultra-depth field microscopy, petrographic microstructure analysis and X-ray fluorescence spectroscopy. The relevant methods of tracing and making clay samples are discussed based on the results of the literature investigation and elemental analysis. The composition, technology and spatial links between different clay sealings collected from all over the country show that highly organized sealing materials and systematic processes are important parts of the establishment of unified China. They also provide detailed and effective scientific information that is useful for the future preservation of clay sealings protection and further archaeological research.
... For a long time, the surface of bronze swords (Fig. 1) was recognized to undergo a treatment of chromate, providing the protection against rust and corrosion. It highlights the advancement of China's ancient metallurgical technology and the ingenuity of ancient Chinese people [7,8]. ...
... However, 27 out of 464 excavated bronze weapons were detected by X-ray fluorescence spectrometer (XRF) to contain elemental chromium with relatively low concentration of about 0.1%wt on each surface [7]. For all bronze weapons, elemental tin with anti-corrosion property was identified in a high concentration ranging from 5%wt to 25%wt [8][9][10]. ...
... Therefore, the recognition on the utilization of chromate coating to prevent bronze weapons from corroding is controversial. It was found that bronze weapons with their non-metallic parts (e.g., wooden hilts, scabbards) coated with lacquer were most likely to show elemental chromium on their surfaces [7,11]. Based on the discovery of elemental chromium in the Qin original lacquer, a possibility that the elemental chromium on some surfaces of bronze weapons was derived from the contamination by lacquer was proposed. ...
The origin of elemental chromium for the archaeological weapons from the pits of Qin terracotta warriors in China has been highly controversial. Although previous studies have highlighted that the chromium on the surface of weapon originated from the contamination of surrounding lacquer, the exact origin of chromium in the lacquer remains unclear. In this work, the measurement by inductively coupled plasma-mass spectrometer (ICP-MS) firstly confirmed that the elemental chromium was indeed contained in the archaeological Qin original lacquer. Nevertheless, the amount of elemental chromium in the Qin lacquer was as low as 0.0759 μg/mg, disclosing that it was impossible to artificially add extra refined chromium-containing substance to the lacquer in the preparation of the terracotta warriors. The soil from the archaeological site of Qin lacquer was found to have a chromium amount of 0.0660 μg/mg by ICP-MS. After the hygrothermal and soil-buried aging cycles for the lab-prepared lacquer, the surface and depth elemental analyses by time of flight-secondary ion mass spectrometer (TOF–SIMS) showed a gradient distribution of elemental chromium from the surface to interior of aged lacquer, indicating the migration and enrichment behavior of elemental chromium from the burial soil towards the lacquer. To explore the migration mechanism of elemental chromium, fluorescence imaging technique was employed in combination with Fourier transform infrared spectrometry (FT-IR) and X-ray photoelectron spectroscopy (XPS) characterizations. The results revealed that catechol-containing fragments were formed during hygrothermal and soil-buried aging of lacquer and consequently coordinated with chromium ions, inducing the migration of elemental chromium towards the lacquer.
... and Ferrum) as well as sodium and magnesium. On the premise of not excluding environmental factors [17], the samples selected for the experiment show the various handling techniques and relatively consistent elemental properties [18]. The data lithotripsy map showed that there are 6 principal components extracted, and the cumulative contribution was 100%. ...
The sealing clay is the key physical example of the document sealing system of the Qin dynasty in ancient China. However, only the inscriptions and aesthetic values of the clay were discussed untill now, and the relevant sources were not traced from the perspective of scientific analysis. A total of 81 sealing clays unearthed in Xi’an were studied by means of ultra-depth of field microscopic observation, petrographic microstructure analysis and X-ray fluorescence spectroscopy. The relevant methods of tracing and making of mud samples are discussed based on the results of literature investigation and element analysis. The composition, technology and spatial links between different sealing clay collected from all over the country show that the highly organized sealing materials and systematic processes are an important part of the establishment of unified China, in order to provide detailed and effective scientific information for the subsequent sealing clay protection and archaeological research.
... 23,24 Similar to the technology for manufacturing the ceramics, details of the making and finishing of the exceptionally wellpreserved bronze artifacts are being investigated, combining factors from metal processing as well as from the environment in which the artifacts were buried over extended times. 25 Depending on the targeted metal quality, increasingly sophisticated roasting and firing technologies were developed in different regions of the world from the early Iron Age, about 2000 years ago. 26,27 Specific furnace constructions were reported to provide the high combustion temperatures that supported the production of high-grade, carbon-containing "damascene" steel (called differently in different regions). ...
Combustion is a reactive oxidation process that releases energy bound in chemical compounds used as fuels─energy that is needed for power generation, transportation, heating, and industrial purposes. Because of greenhouse gas and local pollutant emissions associated with fossil fuels, combustion science and applications are challenged to abandon conventional pathways and to adapt toward the demand of future carbon neutrality. For the design of efficient, low-emission processes, understanding the details of the relevant chemical transformations is essential. Comprehensive knowledge gained from decades of fossil-fuel combustion research includes general principles for establishing and validating reaction mechanisms and process models, relying on both theory and experiments with a suite of analytic monitoring and sensing techniques. Such knowledge can be advantageously applied and extended to configure, analyze, and control new systems using different, nonfossil, potentially zero-carbon fuels. Understanding the impact of combustion and its links with chemistry needs some background. The introduction therefore combines information on exemplary cultural and technological achievements using combustion and on nature and effects of combustion emissions. Subsequently, the methodology of combustion chemistry research is described. A major part is devoted to fuels, followed by a discussion of selected combustion applications, illustrating the chemical information needed for the future.
... This was attributed to intentional patination, although other small finds with similar patina found in the same burial context did not contain such a significant amount of chromium (0.2 wt%) [42] , leading Meeks [43] to dispute the hypothesis of intentional patination of these Chinese bronzes, attributing the presence of the black surface to corrosion phenomena. More recent work offers further evidence for the nonintentional presence of chromium on Chinese bronzes [44] . ...
The study reports a systematic examination and analysis of low-tin wrought bronzes from archaeological burial environments in the Mediterranean. The corrosion profiles occurring on samples taken from thirty-six predominantly Corinthian and Illyrian helmets from excavations in Greece, were analysed using polarised metallography, SEM-imaging, SEM-EDX and X-Ray Diffraction methods. Analysis confirms and expands understanding of existing corrosion models for copper dissolution producing smooth tin enriched patinas that preserve the original surface as a marker layer. SEM-EDX compositional analysis of corrosion profiles with complementary imaging is used to discuss the conditions in which certain corrosion profiles are formed. The study reveals how analysis of samples from many objects of a similar manufacture, buried for similar time periods, can be used to develop detailed understanding of corrosion processes and provide better understanding of the likely appearance of the objects in antiquity.
... Higher percentages of Pb could be added to produce heavier, larger or more complex castings. In such cases, the material is referred to as leaded bronze alloy 14 17 , they can be considered as impurities of the metallurgic process of the ancient bronze. The "niello" decoration on the lid was also analyzed confirming the presence of silver. ...
... Additionally, SEM-EDX measurements revealed a green flake to be mainly composed by Cu, attributable to malachite, co-localization of chromium and iron in an orange flake, probably chromite, a chromium-iron oxide (see Supplementary Fig. S3 online) and a thin metallic flake to be composed of Cu and Zn (see Supplementary Fig. S4 online). They could represent other corrosion products of the inkwell or impurities deriving from the metallurgy, glaze and glass productions of the furnaces 14,17 . ...
A multi-instrumental approach combining highly sensitive Synchrotron Radiation-based techniques was used to provide information on the real composition of a dry black ink powder found in a bronze inkwell of the first century AD. The presence of Pb, Cu and Fe in the powder, revealed by XRF and ICP-OES data, leads to raise several hypotheses on their origin. The inkpot and its lid were also investigated by Hand-Held XRF, revealing a bronze alloy (Cu-Sn) with a certain amount of Fe and Pb. The lid was found to be particularly enriched in lead. XRPD, XAS and FTIR measurements showed a substantial presence of silicates and common clay minerals in the ink along with cerussite and malachite, Pb and Cu bearing-carbonates, respectively. These evidences support the hypothesis of an important contamination of the ink sample by the burial environment (soil) and the presence of degradation products of the bronze inkpot. The combined use of IR, Raman, and GC-MS evidenced that the black ink is mainly composed of amorphous carbon deriving from the combustion of organic material mixed with a natural binding agent, Arabic gum.
... Scholars are interested in whether such chromium was added deliberately by the ancients for anti-rust purposes. However, most investigations [38][39][40] pointed out that the chromium was not an intentional addition but a contamination from the natural environment, except perhaps for one bronze Pan dated to the Warring States Chu Culture [37]. The content of chromium in the sample surface-film by Luo [37] for this bronze Pan is 35.61%, ...
This article presents a generic, objective and evidence based forensic study of 4 very different Chinese bronze mirrors. The work was done within the Architectural Conservation Laboratory (ACLab), the Department of Physics, the Faculty of Medicine and also the Planetary Spectroscopy and Mineralogy Laboratory (PSML) all at the University of Hong Kong. The mirrors nominally cover the period of the Warring States (475–221 BC), Han (206 BC to 220 AD) and later Song (960–1279AD) dynasties. Comprehensive, mostly non-invasive, analytical methods and techniques were used. These included surface microscopy of tool marks, patina, corrosion and any residual archaeological evidence. Ultraviolet radiation examination, chemical spot testing and polarised light microscopy of ground-up patina samples was also done. More sophisticated “pXRF” X-ray fluorescence, “MARS” tomographic X-ray scanning and infrared spectroscopic analysis of the bronze alloys, corrosions and any earthen encrustations were also performed. This was to uncover as much forensic evidence as possible for these unprovenanced bronze mirrors. The results have revealed key metallurgical information of those four mirrors along with surface patina morphology and details of the corrosion and residual surface archaeology. A database on the physical condition of these mirrors has been established and burial/treatment history revealed. Mirrors 1 and 2 appear to have been heavily cleaned, polished and treated with abrasives in modern times. Mirror 2 in particular, has some problematic corrosion and inconclusive alloy composition. Mirror 3 and 4 both have archaeological evidence and no contrary forensic data that questions authenticity. Forensic study and verification of objects and artworks for academic purposes remains a legitimate and vital undertaking for universities, museums and national collections across the globe. Hence, the issue of authenticity when archaeological context is lacking is discussed. However, our key aim is to establish what can be learnt from technological, forensic investigation when studying bronze mirrors without further context and records, and what firm, generic evidence can be extracted from such close forensic examination to shed light on their true nature. We hope this will be useful for other researchers.
... Scholars are interested in whether such chromium was added deliberately by the ancients for anti-rust purposes. However, most investigations [38][39][40] pointed out that the chromium was not an intentional addition but a contamination from the natural environment, except perhaps for one bronze Pan dated to the Warring States Chu Culture [37]. The content of chromium in the sample surface-film by Luo [37] for this bronze Pan is 35.61%, ...
This article presents an objective, evidence based, forensic study undertaken within the HKU Architectural Conservation Laboratory (ACLab) and Department of Physics conducted on 4 very different bronze mirrors from a private collection. They nominally cover the period from the Warring States (475-221BC), Han (206 BC to 220AD) and later Song (960-1279AD) dynasties. Comprehensive, mostly non-invasive, analytical methods and techniques were applied in this endeavour. These included surface microscopy of tool marks, patina, corrosion and any residual archaeological evidence. Ultraviolet radiation examination, chemical spot testing and polarised light microscopy of ground-up patina samples was also undertaken. More sophisticated “pXRF” X-ray fluorescence and “MARS” tomographic X- ray scanning analysis of the bronze alloy, corrosions and any earthen encrustations were also performed. This was all done to uncover as much forensic evidence as possible concerning these unprovenanced bronze mirrors. The combined results have revealed key metallurgical information of those four mirrors along with surface patina morphology and details of the corrosion and residual surface archaeology. A database on the physical condition of these 4 mirrors has been established and burial/treatment history revealed. Mirrors 1 and 2 appear to have been heavily cleaned, polished and treated with abrasives in modern times. Both of them but mirror 2 in particular have some problematic corrosion and inconclusive alloy composition. Mirror 3 and 4 both have archaeological evidence and no contrary forensic data that questions their authenticity. The issue of the possible authenticity of an object when archaeological context is lacking is discussed but this was not the ultimate goal of this research. The key aim is to establish what can be learnt from technological forensic investigation when studying bronze mirrors without archaeological context and records, and what firm evidence can be extracted from such close forensic examination to shed light on their true nature.
Neutron tomography is gaining popularity particularly in cultural heritage research, for non-destructively analysing the inner structure of bulk metal artefacts, such as bronzes, but the induced temporary decay radiation is often considered as a drawback. However, this delayed gamma-emission can be put to good use: by performing gamma spectroscopy after neutron tomography, the interior elemental composition of artefacts can be obtained “for free”. Inspired by this, we propose a ray-tracing approach to non-invasively quantify both interior geometry and elemental composition using only a single neutron tomography experiment. This strategy aligns well with both the aim for efficient use of neutron beam time and the expectation from curators and conservators for minimal neutron irradiation. Here, we outline the core principle of this method, demonstrate the extent of its quantification capability on bulk objects of known composition by fusing neutron tomography and delayed-gamma spectroscopy data sets. We also showcase its practical application on an ancient solid-cast Indonesian bronze statuette, by which we gain insights into how the pristine inner bronze segregated into a different composition than the surrounding shell. Similarly, the method allows us to quantify the composition of a hidden offering in the statuette that consecrates the bronze for worship purposes.
This article presents the results of studying protection methods against corrosion in bronze weapons which were found in the Mausoleum of Qin Shihuangdi. Even during the first season of excavations, well-preserved weapons with traces of chromium on the surface were discovered. Based on these findings, it was suggested that the Qin artisans knew the chromium plating process, when protective film was applied by immersing a bronze item in a container with solution of chromic acid salts. However, this technology is very complicated; it was fully mastered only in the early 20th century. Moreover, less than a dozen weapons were presented as examples of such a technology already in the Qin period (late 2nd century BC), which is not enough for such large-scale conclusions. Therefore, nowadays, an international team of scholars led by M. Martinon-Torres attempted to find a solution to this problem. As a result of their multidisciplinary studies, it has been established that traces of chromium on the surface of weapons are not directly associated with its good preservation. Particles of this metal were contained in lacquered fittings (scabbard, overlays on the handle, etc.), from where they penetrated into the composition of bronze. In the composition of lacquer, chromium ions appeared from treatment with chrome alum, well known to the Qin leatherworkers who could also use it for accelerating polymerization of lacquer tree sap. As far as really good preservation of bronze weapons found in the excavations is concerned, it was explained primarily by specific features of soil in the Mausoleum area (low acidity, fine dispersion, small amount of organic matter, etc.).
