{"id":1367,"date":"2024-11-26T14:26:38","date_gmt":"2024-11-26T06:26:38","guid":{"rendered":"https:\/\/www.tflequip.com\/?p=1367"},"modified":"2024-11-26T14:26:38","modified_gmt":"2024-11-26T06:26:38","slug":"why-does-stainless-steel-rust-and-corrode","status":"publish","type":"post","link":"https:\/\/www.tflequip.com\/sk\/why-does-stainless-steel-rust-and-corrode\/","title":{"rendered":"Pre\u010do nerezov\u00e1 oce\u013e hrdzavie a koroduje?"},"content":{"rendered":"

Pre\u010do nerezov\u00e1 oce\u013e koroduje a hrdzavie? Ke\u010f sa na povrchu nehrdzavej\u00facej ocele objavia hned\u00e9 \u0161kvrny hrdze (bodky), \u013eudia s\u00fa ve\u013emi prekvapen\u00ed: myslia si, \u017ee nehrdzavej\u00faca oce\u013e nekoroduje a nehrdzavie, a ak koroduje a hrdzavie, nie je to nehrdzavej\u00faca oce\u013e a v\u00e4\u010d\u0161ina ocele m\u00e1 probl\u00e9my. V skuto\u010dnosti ide o jednostrann\u00fd a nespr\u00e1vny n\u00e1zor, ktor\u00fd postr\u00e1da pochopenie nehrdzavej\u00facej ocele. Nerezov\u00e1 oce\u013e za ur\u010dit\u00fdch podmienok tie\u017e koroduje a hrdzavie.<\/p>\n

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1. Nerezov\u00e1 oce\u013e bude tie\u017e korodova\u0165 za zodpovedaj\u00facich podmienok<\/p>\n

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Scen\u00e1re pou\u017eitia nehrdzavej\u00facej ocele s\u00fa ve\u013emi zlo\u017eit\u00e9 a jedin\u00fd pasiva\u010dn\u00fd film oxidu chr\u00f3mu nem\u00f4\u017ee splni\u0165 po\u017eiadavky na vysok\u00fa odolnos\u0165 proti kor\u00f3zii. Preto sa pod\u013ea rozdielov v rozsahu pou\u017eitia musia do ocele prid\u00e1va\u0165 prvky ako molybd\u00e9n (Mo), me\u010f (Cu) a dus\u00edk (N), aby sa zlep\u0161ilo zlo\u017eenie pasiva\u010dn\u00e9ho filmu a \u010falej sa zv\u00fd\u0161ila odolnos\u0165 nehrdzavej\u00facej ocele proti kor\u00f3zii. Pridanie Mo vzh\u013eadom na to, \u017ee kor\u00f3zny produkt MoO2- je bl\u00edzko matrice a prudko podporuje pasiv\u00e1ciu matrice, \u010d\u00edm zabra\u0148uje kor\u00f3zii matrice; pridanie Cu sp\u00f4sobuje, \u017ee pasiva\u010dn\u00fd film na povrchu nehrdzavej\u00facej ocele obsahuje CuCl, preto\u017ee nereaguje s koroz\u00edvnymi l\u00e1tkami a zlep\u0161uje odolnos\u0165 proti kor\u00f3zii; pridanie N vzh\u013eadom na to, \u017ee pasiva\u010dn\u00fd film je obohaten\u00fd o Cr2N, koncentr\u00e1cia Cr v pasiva\u010dnom filme sa zvy\u0161uje, tak\u017ee sa zlep\u0161uje odolnos\u0165 nehrdzavej\u00facej ocele proti kor\u00f3zii.<\/p>\n

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Odolnos\u0165 nehrdzavej\u00facej ocele vo\u010di kor\u00f3zii je podmienen\u00e1. Trieda nehrdzavej\u00facej ocele je odoln\u00e1 vo\u010di kor\u00f3zii v ur\u010ditom prostred\u00ed, ale v inom prostred\u00ed sa po\u0161kod\u00ed. Z\u00e1rove\u0148 je kor\u00f3zna odolnos\u0165 nehrdzavej\u00facej ocele aj relat\u00edvna. Zatia\u013e neexistuje nehrdzavej\u00faca oce\u013e, ktor\u00e1 by nikdy nekorodovala vo v\u0161etk\u00fdch prostrediach.<\/p>\n

\".jpg\"<\/p>\n

2. Nerezov\u00e1 oce\u013e nem\u00f4\u017ee korodova\u0165 a hrdzavie\u0165<\/p>\n

 <\/p>\n

Na povrchu sa tie\u017e vytvor\u00ed oxid. D\u00f4vodom, pre\u010do s\u00fa v\u0161etky materi\u00e1ly z nehrdzavej\u00facej ocele na trhu nehrdzavej\u00face, je pr\u00edtomnos\u0165 prvku Cr. Hlavn\u00fdm d\u00f4vodom (princ\u00edpom) odolnosti nehrdzavej\u00facej ocele vo\u010di kor\u00f3zii je koncept pasiva\u010dn\u00e9ho filmu. Zjednodu\u0161ene povedan\u00e9, pasiva\u010dn\u00fd film je film zlo\u017een\u00fd hlavne z Cr2O3, ktor\u00fd pokr\u00fdva povrch materi\u00e1lu z nehrdzavej\u00facej ocele. Vzh\u013eadom na v\u00fdskyt tohto filmu je kor\u00f3zia matrice z nehrdzavej\u00facej ocele v r\u00f4znych m\u00e9di\u00e1ch obmedzen\u00e1. T\u00e1to situ\u00e1cia sa naz\u00fdva pasiv\u00e1cia. Existuj\u00fa dve situ\u00e1cie vzniku tohto typu pasiva\u010dn\u00e9ho filmu. Jednou z nich je, \u017ee samotn\u00e1 nehrdzavej\u00faca oce\u013e m\u00e1 schopnos\u0165 samopasiv\u00e1cie. T\u00e1to samopasiva\u010dn\u00e1 schopnos\u0165 sa zr\u00fdch\u013euje so zvy\u0161ovan\u00edm obsahu chr\u00f3mu, tak\u017ee m\u00e1 odolnos\u0165 proti kor\u00f3zii; druhou be\u017enej\u0161ou v\u00fdrobnou podmienkou je, \u017ee nehrdzavej\u00faca oce\u013e vytv\u00e1ra pasiva\u010dn\u00fd film v procese kor\u00f3zie v r\u00f4znych vodn\u00fdch roztokoch (elektrolytoch), \u010d\u00edm obmedzuje kor\u00f3ziu. Ke\u010f sa pasiva\u010dn\u00fd film po\u0161kod\u00ed, m\u00f4\u017ee sa okam\u017eite vytvori\u0165 nov\u00fd pasiva\u010dn\u00fd film.<\/p>\n

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Existuj\u00fa tri d\u00f4vody, pre\u010do m\u00e1 pasiva\u010dn\u00fd film z nehrdzavej\u00facej ocele schopnos\u0165 odol\u00e1va\u0165 kor\u00f3zii: po prv\u00e9, hr\u00fabka pasiva\u010dn\u00e9ho filmu je ve\u013emi tenk\u00e1, \u010do m\u00f4\u017ee by\u0165 len nieko\u013eko mikr\u00f3nov v prostred\u00ed s obsahom chr\u00f3mu > 10.5%; po druh\u00e9, \u0161pecifick\u00e1 hmotnos\u0165 pasiva\u010dn\u00e9ho filmu je v\u00e4\u010d\u0161ia ako \u0161pecifick\u00e1 hmotnos\u0165 substr\u00e1tu; tieto dve vlastnosti nazna\u010duj\u00fa, \u017ee pasiva\u010dn\u00fd film je tenk\u00fd a z\u00e1rove\u0148 hust\u00fd, tak\u017ee je \u0165a\u017ek\u00e9, aby pasiva\u010dn\u00fd film prenikol koroz\u00edvnym prostred\u00edm a r\u00fdchlo skorodoval substr\u00e1t; tre\u0165ou vlastnos\u0165ou je, \u017ee koncentr\u00e1cia chr\u00f3mu v pasiva\u010dnom filme je viac ako trikr\u00e1t vy\u0161\u0161ia ako koncentr\u00e1cia chr\u00f3mu v substr\u00e1te; preto m\u00e1 pasiva\u010dn\u00fd film vysok\u00fa odolnos\u0165 proti kor\u00f3zii.<\/p>\n

 <\/p>\n

Nerezov\u00e1 oce\u013e m\u00e1 schopnos\u0165 odol\u00e1va\u0165 atmosf\u00e9rickej oxid\u00e1cii, teda nehrdzavie, a m\u00e1 tie\u017e schopnos\u0165 nekorodova\u0165 v m\u00e9di\u00e1ch obsahuj\u00facich kyseliny, z\u00e1sady a soli, teda odolnos\u0165 proti kor\u00f3zii. Jej odolnos\u0165 proti kor\u00f3zii sa v\u0161ak l\u00ed\u0161i v z\u00e1vislosti od chemick\u00e9ho zlo\u017eenia samotnej ocele, stavu ochrany, rozsahu pou\u017eitia a typu prostredia. Napr\u00edklad oce\u013eov\u00e9 r\u00fary 304 maj\u00fa relat\u00edvne dobr\u00fa odolnos\u0165 proti kor\u00f3zii v suchom a \u010distom prostred\u00ed, ale ke\u010f sa premiestnia do pobre\u017en\u00fdch oblast\u00ed, v morskej hmle obsahuj\u00facej v\u00e4\u010d\u0161ie mno\u017estvo soli r\u00fdchlo hrdzavej\u00fa; zatia\u013e \u010do oce\u013eov\u00e9 r\u00fary 316 dosahuj\u00fa dobr\u00e9 v\u00fdsledky. Preto nie ka\u017ed\u00e1 nehrdzavej\u00faca oce\u013e je odoln\u00e1 vo\u010di kor\u00f3zii a nehrdzavie vo v\u0161etk\u00fdch prostrediach.<\/p>","protected":false},"excerpt":{"rendered":"

Why does stainless steel corrode and rust? When brown rust spots (dots) appear on the surface of stainless steel, people are very surprised: they think that stainless steel will not corrode and rust, and if it corrodes and rusts, it is not stainless steel, and most of the steel has problems. In fact, this is […]<\/p>","protected":false},"author":4,"featured_media":1368,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[36],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/www.tflequip.com\/sk\/wp-json\/wp\/v2\/posts\/1367"}],"collection":[{"href":"https:\/\/www.tflequip.com\/sk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tflequip.com\/sk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tflequip.com\/sk\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tflequip.com\/sk\/wp-json\/wp\/v2\/comments?post=1367"}],"version-history":[{"count":0,"href":"https:\/\/www.tflequip.com\/sk\/wp-json\/wp\/v2\/posts\/1367\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.tflequip.com\/sk\/wp-json\/wp\/v2\/media\/1368"}],"wp:attachment":[{"href":"https:\/\/www.tflequip.com\/sk\/wp-json\/wp\/v2\/media?parent=1367"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tflequip.com\/sk\/wp-json\/wp\/v2\/categories?post=1367"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tflequip.com\/sk\/wp-json\/wp\/v2\/tags?post=1367"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}