Occurrence of phosphatic corrosion products on bronze swords of the Warring States period buried at Lijiaba site in Chongqing, China

Abstract

Corrosion products on three bronze swords found in tombs dating from the Warring States period at Lijiaba site, Yunyang county, Chongqing were characterized by Raman and X-ray fluorescence spectroscopies. The major corrosion products were cuprite, malachite, cerussite and cassiterite, along with the copper and lead phosphates, libethenite and pyromorphite. The presence of libethenite and pyromorphite which have been reported infrequently in bronze corrosion products were attributed to the pH, humidity and phosphorus released by the decomposition of the adjacent bodies in the burial environment.