Nanoscale Tang Dynasty Metal analysis

Published: 24. July 2024
Category: Natural Sciences
Author: Ioannis Liritzis & more

Over the years, numerous gold and silver artifacts have been excavated from the tombs of the Tang dynasty, which give evidence of the sophisticated metalworking techniques at that time. Few of the artifacts were thoroughly studied and their manufacturing processes were barely known. The present investigation concerns a metal headgear from a newly excavated tomb of a female in Xi’an of the Tang dynasty (618–907 A.D.), using advanced techniques in a complementary way, especially performing a detailed analysis of the corrosion products and alloying processes. The combined state-of-the-art methods and instrumentation used for the corrosion study included spectroscopy, diffraction, electron microscopy, synchrotron and their versions for specific measurements and sample preparation. The investigated headgear metal consists of a copper-based core, which is gilded by a thin gold layer, consisting of an Au–Hg alloy with a thin layer of about 400 nm. The technique used for shaping and hammered embellishments led to the creation of nanosized grains on the side that would eventually be the interior of the headgear.

It was gilded using the mercury-amalgamation process, and the liquid diffusion caused the development of intermetallic compounds. This is the first recorded instance of these nano-scale and eutectic phases being observed on objects from an archaeological context. The crystallographic analysis offered valuable insights into the formation of needle-like malachite crystals growing on a layer of cuprite found on the surface of the corroded piece. The results highlight that the artisans utilized advanced methods in the creation of funerary items during the Tang dynasty... FULL ARTICLE

 Authors: Ioannis Liritzis, Sophie Cazottes, Thierry Douillard, Muriel Véron, Josep Roqué-Rosell, Carlo Marini, Partha Pratim Das,  Alejandro Gomez-Perez, Athanassios S. Galanis, Stavros Nicolopoulos, Panagiota Manti,  Junchang Yangh and Xiangyu Zhangi

Prof. Ioannis Liritzis: Laboratory of Yellow River Cultural Heritage, Key Research Institute of Yellow River Civilization and Sustainable Development & Collaborative Innovation Center on Yellow River Civilization, Henan University, Kaifeng 475001Minglun Road 85, China.

 

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