한국주조공학회

The effects of Bi and Sb additions on the microstructures and casting properties in lead-free Cu- Zn-Sn broze were investigated. (1) When only Bi was added to the bronze, Bi was precipitated on the δ phase of α dendrite cell boundary. When Bi and Sb were added together, Bi was precipitated on the δA which was the Sb-rich area in the δ phase. (2) The addition of Sb accelerated the formation of δ phase, and when Sb, Bi and Pb were added, Bi and Pb were precipitated as mixed solution in the δA phase. (3) The combined addition of Sb and Bi resulted in the suppression of shrinkage due to the complementary effects of the mass feeding of α- dendrite cluster covered with δ phase and sealing of micro-shrinkage in the δ phase by solidification expansion of Bi.

Lead-free, Bronze Castings, Bi and Sb additions.