Simbi isina tsvina haikurumidzi kuita ngura, ngura kana kusviba nemvura sezvinoita simbi yakajairika. Nekudaro, haina kuzara-uchapupu mune yakaderera-oxygen, yakakwirira-munyu, kana isina kunaka-inotenderera mhepo nharaunda. Kune magiredhi akasiyana-siyana uye kupera kwepamusoro kwesimbi isina tsvina kuti ienderane nenharaunda iyo alloy inofanirwa kutsungirira. Simbi isina tsvina inoshandiswa uko zvese zviri zviviri simbi uye corrosion resistance inodiwa.

Simbi isina tsvina inosiyana nekabhoni simbi nehuwandu hwechromium iripo. Kabhoni simbi isina kudzivirirwa inoita ngura zviri nyore kana yaiswa mumhepo nehunyoro. Iyi iron oxide film (iyo ngura) inoshanda uye inokurumidza kuonda nekugadzira iron oxide yakawanda[kujekesa kunodiwa]; uye, nokuda kwehuwandu hukuru hwe iron oxide, izvi zvinowanzoita kuputsika uye kudonha. Simbi dzisina simbi dzine chromium inokwana kuita firimu rechromium oxide, rinodzivirira kumwe kukora kwepamusoro nekuvharira kupararira kweokisijeni panzvimbo yesimbi uye inovharira ngura kuti isapararire mukati mesimbi. Passivation inoitika chete kana chikamu chechromium chakakwira zvakakwana uye oxygen iripo.