The primary difference between copper wire and tinned copper wire lies in the surface treatment applied to the wire:

Copper Wire:

Copper wire is made of pure copper without any additional surface treatment.
It has a natural copper color and appearance.
Copper wire is highly conductive and is commonly used in electrical applications where conductivity is critical.
While copper itself is resistant to corrosion, it can oxidize over time, leading to a dull appearance and potentially affecting conductivity.
Tinned Copper Wire:

Tinned copper wire is copper wire that has been coated with a thin layer of tin through a process called "tinning."
The tinning process involves immersing the copper wire in a bath of molten tin or applying a layer of tin through electroplating.
The tin coating provides several benefits, including enhanced corrosion resistance, solderability, and durability.
Tinned copper wire has a silver-colored appearance due to the tin coating, which distinguishes it from bare copper wire.
The tin coating acts as a barrier against oxidation and corrosion, helping to maintain the electrical conductivity of the wire over time, even in harsh environments.
Tinned copper wire is commonly used in marine, automotive, and aerospace applications, as well as in electronics and electrical wiring where corrosion resistance and solderability are important.