| Abstract | Različiti metali se primjenjuju svakodnevno u izgradnji cjevovoda i drugih konstrukcija te stoga ne čudi pridavanje velikog zanimanja njihovoj zaštiti od vanjskih utjecaja, tj. utjecaja okoline koji dovode do njihove korozije. U današnje vrijeme postoje razni načini za zaštitu materijala od korozije, ali ako se razmatraju cjevovodi, onda je najčešći način njihove zaštite, uz korištenje organskih premaza, katodna zaštita. Ovaj diplomski rad bavi se kontrolom katodne zaštite na štićenoj konstrukciji, odnosno određivanjem potencijala štićene konstrukcije, kao glavnim kriterijem djelotvornosti katodne zaštite. U tu svrhu ispitivani su kuponi bez IR pada napona (engl. IR-free) koji se upotrebljavaju za mjerenje uključno-isključnog (ON-OFF) potencijala na način da svojom konstrukcijom uklanjaju dodatnu komponentu pada potencijala u elektrolitu (IR komponentu). Za provođenje ispitivanja izrađen je IR-free kupon na temelju postojećih komercijalnih kupona. Tijekom mjerenja se, osim načina ostvarivanja katodne zaštite na konstrukciji, mijenjala i ispuna Lugginove kapilare (vodovodna voda, zemlja i smjesa bentonita i kvarca u vodovodnoj vodi), koja je bila dio konstrukcije IR-free kupona te elektrolit u kojem se eksperiment provodio. Nadalje, parametri čiji se utjecaj na veličinu dodatnog pada potencijala u elektrolitu pratio su bili duljina Lugginove kapilare i promjer njezina dna. Konačna ideja samoga rada je, dakle, bila ispitati uklanjaju li stvarno IR-free kuponi u potpunosti dodatni pad potencijala u elektrolitu i ako ne u kojoj ga mjeri smanjuju. Pritom je kupon bio izrađen od konstrukcijskog čelika, a referentna elektroda je bila Cu/CuSO4 referentna elektroda. Na kraju istraživanja provedena je karakterizacija komercijalnih kupona. |
| Abstract (english) | Different metals are used every day in the construction of pipelines and other structures, and therefore it is not surprising that there is a great interest in their protection from external influences, i.e. environmental influences that lead to their corrosion. Nowadays, there are various ways to protect materials from corrosion, but if pipelines are considered, then the most common way to protect them, along with the use of organic coatings, is cathodic protection. This diploma work deals with controlling the cathodic protection on the protected structure, that is, determining the potential of the protected structure, as the main criterion for the effectiveness of the cathodic protection. For this purpose, IR-free coupons were tested, which are used to measure the structure ON-OFF potential, in such a way that their design removes the potential drop component in the electrolyte (IR component). An IR-free coupon based on existing commercial coupons was created. During the measurement, in addition to the method of cathodic protection, the filling of the Luggin capillary (tap water, soil and a mixture of bentonite and quartz in the tap water), which was part of the construction of the IR-free coupon, and the electrolyte in which the experiment was conducted, was examined. Furthermore, the influence of length of the Luggin capillary and the diameter of its bottom on the size of the additional potential drop in the electrolyte was studied. The final idea of the work was to examine whether IR-free coupons completely remove the additional potential drop in the electrolyte and, if not, to what extent they reduce it. The coupon was made of structural steel, and the reference electrode was a Cu/CuSO4 electrode. At the end of the research, the characterization of commercial coupons was carried out. |
