The constituents of permalloy are Iron and

Permalloy is an alloy composed of iron (Fe) and nickel (Ni), typically in a ratio of approximately 20% iron and 80% nickel, though the exact composition can vary.

Permalloy is valued for its exceptionally high magnetic permeability, meaning it is very easily magnetised even by weak magnetic fields. This property makes it useful in:

• Transformer cores
• Magnetic shielding
• Recording heads in data storage devices
• Sensitive magnetic instruments

The other metals listed form different alloys with iron:

• Iron + tin = tin plate (tin-coated iron, used for food cans)
• Iron + chromium (plus nickel and carbon) = stainless steel
• Iron + copper is not a standard named alloy

The defining feature of permalloy is that it is a nickel-iron alloy.