Boron/Lithium-based flux in 18th Century Chinese porcelain enamels: PIXE/PIGE study.
BURLOT J. 1, BELLOT-GURLET L. 1, LEMASSON Q. 3, PICHON L. 3, COLOMBAN P. 2
1 MONARIS UMR8233, Sorbonne Université, Paris, France; 2 MONARIS UMR8233, Sorbonne Université, CNRS, Paris, France; 3 Centre de Recherche et de Restauration des Musées de France (C2RMF), Paris, France
Li and B elements are difficult to measure, especially through non-invasive methods, and are generally neglected in glaze studies. However, recent researches on Byzantine glass and Ottoman ceramic glazes show the use of a soda-rich evaporite from western Anatolian hot springs associated with borax deposits from this region [1-2]. Borax, indeed, not only contributes to lower the melting temperature but also to control the wettability and viscosity. Raman microspectroscopy analyses evidenced also the use of borax in Chinese enamels, following the recipe of the 1753 manuscripts of the French chemist Jean Hellot [3-4]. Following these initial analyses, we performed non-destructive PIXE/PIGE analyses to better characterize the Li and B contents in the enamels of seven porcelain shards dating from the 18th century to observe potential technology transfers between Europe and China. We selected one soft-paste porcelain plate from Sèvres (France), and six Chinese samples: one Imari-style dish, three Famille rose plates, one blue-and-white plate and one imperial bowl with a falangcai decoration.
To approach the local elemental composition of the silicate matrix, PIXE/PIGE measurements were performed on profiles through decorations of different enamel colors. The objective was to compare European and Chinese glaze by defining their raw materials and the enameling techniques executed by the craftsmen, respectively. These definitions were then used to illustrate transfers of know-how that occurred from Europe to China during that time. We will thus present the data resulting from the PIXE/PIGE analyses, by discussing first the correlation between the Raman and the elemental composition data and, in a second time, by attributing them more specifically to technical traditions, which will enrich our knowledge on the History of techniques and in particular that of Chinese enamelling.
1] Tite et al., 2016, Archaeometry 58(1): 56-67.
2] Burlot et al., 2022, 43rd International Symposium on Archaeometry (communication).
3] Colomban et al., 2022, Heritage 5(1): 233-259.
4] Colomban, 2022, Materials 15(9): 3158.
Keywords: Local composition, Enamel, Flux, Boron, PIXE/PIGE