Anvils allow you to rename items, repair enchanted items, and even combine the enchantments from different items, at the cost of experience points. Crafting. You'll need 3 blocks of iron, plus 4 more iron bars, for a total of 31 iron bars.
Passivation is the treatment of the surface of stainless steels, often with acid solutions (or pastes), to remove contaminants and promote the formation of the passive film on a freshly created surface (e.g. through grinding, machining or mechanical damage).
Pickling and Passivation are different forms of chemical metal finishing that provide protection on the surface of the metals. The process of doing pickling and passivation on a metal is not much of a difference. They both remove imperfections and rust on the surface of the metal.