In the world of Olympic lifting we've got plenty of options when shopping for a bar. The key things to look out for are:
Bar material. As the bar is being dropped it really needs to be made from spring steel. This is a high tensile steel which is actually an alloy, not plain old mild steel. It has hardening alloys in the steel to increased its load capacity. It also allows the bar to flex without being permanently bent upon impact. Spring steel bars can handle high impact thanks to this increased flex. This does mean the bar will 'whip' a little - its the material springing back to its original shape.
Coating. Now we all know oxide...