After a metal object turns to dust (rust), it would have no entropy low entropy high entropy

high entropy

Explanation:

Entropy is the measure of randomness or disorder of a system.

If a system moves from  an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

According to second law of thermodynamics, all spontaneous processes lead to increase in entropy.

Thus as rusting is a spontaneous process, it happens on its own,  randomness increases and thus entropy also increases.