 Antimony forms a highly useful alloy with lead , increasing its hardness and mechanical strength . For most applications involving lead , varying amounts of antimony are used as alloying metal . In lead – acid batteries , this addition improves the charging characteristics and reduces generation of unwanted hydrogen during charging . It is used in antifriction alloys ( such as Babbitt metal ) , in bullets and lead shot , cable sheathing , type metal ( for example , for linotype printing machines ) , solder ( some " lead @-@ free " solders contain 5 % Sb ) , in pewter , and in hardening alloys with low tin content in the manufacturing of organ pipes . 
