What are the base materials of Chain Mail Armor?

You can repair a chain armor with iron ingots.

Here's the wiki paragraph:

Anvils can also repair a piece of armor using units of that armor's base material. Chain armor can be repaired in this manner by using iron ingots.

There are three different answers to this question:

• For use in anvil repairing, iron ingots are used.
• For use in crafting table repairing, another peice of the same armor must be used.
• For use in crafting the armor, fire must be used (unobtainable in Survival).

To obtain Chainmail armor, one must either kill a mob wearing such armor or trade with villagers.