Why are the copper terminals more

The working characteristic of conductor Terminals is to connect and conduct electricity, so the material of the terminals should also meet its working conditions.  Conductivity is one of the best gold, silver, copper, the former two cost is too high, pure copper relative cost is low, can satisfy its technical requirements, so now the conductor terminal are mostly choose pure copper stainless steel because joined the chromium, niobium, nickel alloy elements, such as increased resistance to electric conductivity drops greatly, not suitable for used as conductor terminal wire terminals of hardness shoulds not be too big,  Hardness is too large combination is not good, the effective contact surface of the terminal will become smaller, the cross-sectional area of the conduction current will be limited, this is why to hang tin on the terminal surface, tin hardness is soft, can make the terminal surface fully combined.