Characterization of the micro-contaminants from the inner-body of Kraak porcelain excavated from the \u201cNan\u2019ao I\u201d shipwreck, the South China Sea

Jingnan Du,Changsui Wang,Naisheng Li,Wugan Luo

doi:10.1186/s40494-019-0328-0

Abstract

In this paper, optical microscopy, SEM–EDS, Raman and FT-IR analyses were used to investigate different types of corrosion product between layers of glaze and body of Kraak porcelain objects that were excavated from “Nan’ao I” shipwreck, the South China Sea. Several contaminants including NaCl, CaSO4·2H2O, FeOOH and FeS2, were found in many of the pores and cracks of the porcelain objects from Jingdezhen Kiln and Zhangzhou Kiln, even after conservation. While compared with the sample of Jingdezhen Kiln, the contaminants in the sample of Zhangzhou Kilns much more severely. The research pointed out that these contaminants were formed due to the marine environment influence and cross-contamination with other metal relics located in the shipwreck, and more contaminants formed in porous structure, hence reduce the porcelain quality. As regards to conservation, the fragility of ceramic objects from underwater contexts are likely to be caused by various kinds of insoluble ferrous salts and its phase transition pressure. Previous studies on this kind of remains tend to focus on the macro-insoluble salts on the enamel surface. In this paper, preliminary investigations were performed for the first time on different kinds of inner micro-corrosion product in China.

Highlights

Kraak porcelain was one of the most famous and fashionable manufactures exported to the entire European continent, when in the period from the Jiangjing reign late-Ming dynasty to the Qianlong reign early-Qing dynasty (~ 1550 A.D. to 1700 A.D.) [1]
The “Nan’ao I” shipwreck, which contains over 20,000 Kraak porcelain items, was preliminary identified as a merchant ship of the Jiajing to Longqing reigns (~ 1522 A.D to 1572 A.D.), a period marked by the beginning of an
The analyses conducted on two pieces of Kraak porcelain from the “Nan’ao I” shipwreck showed that NaCl was not the only inner contaminant

Summary

Introduction

Kraak porcelain was one of the most famous and fashionable manufactures exported to the entire European continent, when in the period from the Jiangjing reign late-Ming dynasty to the Qianlong reign early-Qing dynasty (~ 1550 A.D. to 1700 A.D.) [1]. It played an essential role in the ancient Maritime Silk Road, and exerted a significant influence in oversea ceramic trade. The shipwreck is 25.5 m long and 7.8 m wide and it sank at a depth of 27 m underwater It has 26 compartments, being one of the biggest ships of the Ming dynasty ever found in China [3]. Kraak porcelain items account for 90% of the remains [4]

Methods

Discussion

Conclusion