From: A study on ancient casting method via microstructures of impurities and copper found in bronze excavated from the Unified Silla Period (7th to 10th centuries)
O
Si
S
Fe
Cu
Pb
①
4.14
–
1.91
0.58
93.20
0.18
②
42.31
1.58
0.34
55.47
③
52.19
11.31
6.55
3.42
2.10
24.42