I think it most unlikely that zang (žang) “rust” and zang “bell” are the same word. Neither has convincing cognates outside of Iranian, though the first has been widely borrowed (Armenian, Georgian and others).
I think the 2 words (rust and bell) are unrelated.
In Turkish the word for bell is çan, originally çang/çaŋچاڭ (written with nasal kâf-i nûnî in Ottoman Turkish). It is certainly an Old Turkic word that is present in other Turkic languages too which were outside the Perso-Islamic influence (like cognates of the word are also present in Altai, Teleut, Shor, Khakas). Clauson wrote that it is obviously onomatopoeic that is impossible to determine whether it is a native Turkic word, or a loanword from for example Chinese 鐘 zhong "bell" 鐘 - Wiktionary or Persian چنگ chang (which is then the origin of Arabic صنج sanj "cymbal") meaning "harp, lute, cymbals". Also there is the Persian سنج "cymbal", I don't know is this a later reborrowing from Arabic??
Personally I would vote for an ultimately Chinese origin for the bell, I don't know though if it reached Persian directly from it or through Turkic.
Maybe the Hungarian cseng (to ring) is also a loanword from Turkic or similarly developed onomatopoeic word.