In the Eastern Zhou Dynasty

there are a kind of bronze weapons in the Wu and Yue areas

which have lozenge shaped pattern on the surface. Archaeologists and scientists have paid much attention to it since seventies. A fragment of a lozenge shaped pattern sword is examined and analyzed. It is found that the sword was cast with bronze alloy. There was a thin fine dendrite layer in some areas of the fragment surface. Its structure and compositions are different from the matrix in this fragment. This fine dendrite layer has a higher corrosion resisting ability and could protect the sword matrix from corrosion. Several methods of forming the lozenge shaped pattern are simulated

and then a process named tin rich paste coating treatment could successfully form a fine dendrite layer on bronze weapons similar to that of the ancient fragment.