Ukuxhatshazwa okugqwesileyo kwe-corrosion yensimbi engenasici kubangelwa ukubunjwa kwefilimu ye-oxide engabonakaliyo ebusweni bentsimbi, eyenza i-passive.Le filimu ye-passive yenziwa ngenxa yensimbi ephendula nge-oxygen xa ibonakaliswe emoyeni, okanye ngenxa yokunxibelelana nezinye iindawo ezine-oksijini.Ukuba ifilimu ye-passivation iyatshatyalaliswa, insimbi engenasici iya kuqhubeka nokugqwala.Kwiimeko ezininzi, ifilimu ye-passivation itshatyalaliswa kuphela kumphezulu wesinyithi nakwiindawo zendawo, kwaye umphumo wokubola kukwenza imingxuma emincinci okanye imingxuma, okukhokelela ekuhanjisweni ngokungaqhelekanga kwi-corrosion encinci efana nomngxuma kumphezulu wezinto eziphathekayo.
Ukwenzeka kwe-pitting corrosion kungenzeka ngenxa yobukho be-chloride ion zidityaniswe ne-depolarizers.I-corrosion ye-pitting ye-metals passive efana nentsimbi engapheliyo idla ngokubangelwa ngumonakalo wendawo yee-anion ezithile ezinobundlongo kwifilimu ye-passive, ekhusela i-passive state kunye nokumelana nokunyuka okuphezulu.Ngokwesiqhelo kufuneka indawo ene-oxidizing, kodwa le yimeko kanye eyenzeka phantsi kwayo umhlwa.I-medium for pitting corrosion kubukho bee-ion zetsimbi ezinzima ezifana ne-FE3 +, Cu2 +, Hg2 + kwi-C1-, Br-, I-, Cl04-isisombululo okanye izisombululo ze-chloride ze-Na+, i-Ca2+ yealkali kunye ne-alkaline yomhlaba i-ion zetsimbi equkethe i-H2O2, i-O2, njl.
Izinga lokungena liyenyuka ngokunyuka kwamaqondo obushushu.Ngokomzekelo, kwisisombululo esine-concentration ye-4% -10% ye-sodium chloride, ukulahlekelwa kwesisindo esiphezulu ngenxa ye-corrosion ye-pitting ifike kwi-90 ° C;kwisisombululo esincinci, ubuninzi buvela kwiqondo lokushisa eliphezulu.
Ixesha lokuposa: Feb-24-2023