Xa kuvela amachokoza amdaka (amabala) kumbhobho wentsimbi engatyiwayo, abantu bayothuka gqitha: “Intsimbi engagqwali ayivusi, yaye ukuba iyarusa, asiyontsimbi engatyiwayo, yaye kusenokubakho ingxaki ngentsimbi.”Enyanisweni, oku kuyingcamango ephosakeleyo enye malunga nokungabikho kokuqonda kwensimbi engenasici.Insimbi engenasici iya kuhlwa phantsi kweemeko ezithile.
1. Intsimbi engatyiwayo ayinamhlwa
Insimbi engenasici nayo ivelisa i-oxide phezu komhlaba.Indlela yomhlwa yazo zonke iintsimbi ezingenastainless ngoku kwimarike kungenxa yobukho be-Cr element.Oyena nobangela (inkqubo) yokuxhathisa umhlwa yintsimbi yethiyori yokwenziwa.Ifilimu ebizwa ngokuba yi-passivation film yifilimu encinci kakhulu eyenziwe yi-Cr2O3 kumphezulu wensimbi engenasici.Ngenxa yobukho beli filimu, ukubola kwe-substrate yensimbi engenasici kumajelo ahlukeneyo kuthintelwe, kwaye le nto ibizwa ngokuba yi-passivation.Kukho iimeko ezimbini zokuqulunqwa kwale filimu ye-passivation.Enye kukuba insimbi engenasici ngokwayo inamandla okuzimela, kwaye lo buchule bokuzikhupha buphuthunyiswa ngokunyuka komxholo we-chromium, ngoko unokumelana nokugqwala;Imeko yokwakheka ebanzi ngakumbi kukuba insimbi engenasici yenza ifilimu ye-passivation kwinkqubo yokutshatyalaliswa kwiisombululo ezahlukeneyo zamanzi (i-electrolytes), ethintela ukubola.Xa ifilimu ye-passivation yonakele, ifilimu entsha ye-passivation inokwakheka ngokukhawuleza.
Isizathu sokuba ifilimu ye-passive yensimbi engenasici inamandla okumelana ne-corrosion ineempawu ezintathu: enye kukuba ubukhulu befilimu ye-passive buncinci kakhulu, ngokuqhelekileyo kuphela ii-microns ezimbalwa xa umxholo we-chromium> 10.5%;enye i-gravity ethile yefilimu ye-passive inkulu kunobunzima obuthile be-substrate;ezi mpawu zimbini zibonisa ukuba ifilimu ye-passivation incinci kwaye ixinene, ngoko kunzima ukuba ifilimu ye-passive iphulwe yi-corrosive medium ukuba idle ngokukhawuleza i-substrate;uphawu lwesithathu kukuba i-chromium concentration ratio yefilimu ye-passive I-substrate ingaphezulu kwamaxesha amathathu aphezulu;ngoko ke, ifilimu ye-passive inokumelana nokugqwala okuphezulu.
2. Ngaphantsi kweemeko ezithile, insimbi engenasici nayo iya kugqwala
Indawo yokusetyenziswa kwensimbi engenasici inzima kakhulu, kwaye ifilimu elula ye-chromium oxide ayinakuhlangabezana neemfuno zokumelana nokubola okuphezulu.Ngoko ke, izinto ezifana ne-molybdenum (Mo), ubhedu (Cu), kunye ne-nitrogen (N) kufuneka zongezwe kwintsimbi ngokweemeko ezahlukeneyo zokusetyenziswa ukuze kuphuculwe ukubunjwa kwefilimu ye-passivation kunye nokuphucula ngakumbi ukuxhatshazwa kwe-corrosion yensimbi engenasici.Ukongezwa kwe-Mo kukhuthaza kakhulu i-passivation edibeneyo ngenxa yokuba imveliso ye-corrod MoO2- isondele kwi-substrate kwaye ikhusela ukubola kwe-substrate;ukongezwa kweCu kwenza ifilimu ye-passive kwi-stainless steel surface iqulethe i-CuCl, ephucula ukusebenza kakuhle kwefilimu ye-passive ngenxa yokuba ayihambelani ne-corrosive medium.Ukumelana nokubola;ukongeza i-N, ngenxa yokuba ifilimu ye-passivation ityetyiswe nge-Cr2N, i-Cr concentration kwifilimu ye-passivation iyanda, ngaloo ndlela iphucula ukuxhathisa kwe-corrosion yensimbi engenasici.
Ukuxhatshazwa kwe-corrosion of steel stainless kunemiqathango.Ibakala lentsimbi engatyiwayo liyakwazi ukumelana nomhlwa kwindawo ethile, kodwa lingonakala kwenye indawo.Ngexesha elifanayo, ukuxhathisa kwe-corrosion yensimbi engenasici nako kuhlobene.Ukuza kuthi ga ngoku, akukho ntsimbi engagqwaliyo engonakalisi kwaphela kuzo zonke iindawo.
Insimbi engenasici inamandla okuxhathisa i-oxidation ye-atmospheric-oko kukuthi, ukuxhathisa umhlwa, kwaye ikwazi ukubola kwimidiya equkethe i-acids, i-alkali, kunye neetyuwa-oko kukuthi, ukuxhathisa ukubola.Nangona kunjalo, ubukhulu bekhono layo lokuchasana ne-corrosion litshintshwa kunye nokwakheka kweekhemikhali zensimbi ngokwayo, indawo yokukhusela, iimeko zokusetyenziswa kunye nohlobo lweendaba zokusingqongileyo.Umzekelo, umbhobho wentsimbi we-304 unamandla abalaseleyo okuchasa umhlwa kwindawo eyomileyo necocekileyo, kodwa ukuba ithe yasiwa kwindawo yolwandle, iya kugqwala kungekudala kwinkungu yolwandle equlethe ityuwa eninzi;ngelixa umbhobho wentsimbi we-316 ubonisa okulungileyo.Ngoko ke, akusiyo nayiphi na insimbi engenasici enokuthi ixhathise i-corrosion kunye ne-rust kuyo nayiphi na indawo.
Ixesha lokuposa: Sep-23-2022