3390 KB27 KB199920252016Campian, Viorel ConstantinCiubotariu, Costel-ReluFrunzaverde, DoinaMarginean, GabrielaSecosan, Evelinaletnik:62številka:nr. 3str. 154-162ISSN:0039-2480COBISSID_HOST:14547739URN:URN:NBN:SI:doc-TINGMXZ7enZveza strojnih inženirjev in tehnikov Slovenije etc.Strojniški vestnikhidravlični strojikorozijska odpornostlasersko pretaljevanjeplamenska obdelavasamotaljive zlitineStellite 6toplotno nabrizgavanjeExperimental study regarding the cavitation and corrosion resistance of Stellite 6 and self-fluxing remelted coatings|This paper aims to compare cobalt-based (type Stellite 6) and nickel-based self-fluxing alloys (type NiCrBSiMo) regarding both their cavitation erosion resistance and corrosion resistance. The two types of protective layers were thermally sprayed onto a substrate of martensitic stainless steel. In order to improve the layers% characteristics and their metallurgical bonding to the substrate, the Stellite 6 coating was laser remelted, while the NiCrBSiMo coating was treated by flame fusion. The cavitation erosion resistance of the two materials was evaluated by measurements of the mean depth of erosion developed during a testing period of 165 minutes, using a 20 kHz ultrasonic vibrator at a peak-to-peak amplitude of 50 %m. In addition, the corrosion resistance of the layers was assessed by potentiodynamic corrosion tests carried out in H 2 SO 4 + NaCl solution at room temperature, using calomel as reference electrode. In order to highlight the differences regarding the behaviour of the two protective materials, the authors also carried out microstructural investigations of the layers before and after exposure to cavitation and corrosion. The investigations showed that both types of layers can provide improved protection of the martensitic stainless steel substrate against cavitation, whilst the NiCrBSiMo coating additionally confers significantly increased resistance to corrosionKakovost vodne energije je odvisna od vzdržljivosti in zanesljivosti hidravličnih strojev. Površinske poškodbe zaradi utrujanja, korozije in obrabe, še posebej pa zaradi kavitacijske erozije, so glavni vzrok odpovedi komponent v hidroelektrarnah. Kavitaciji pri vodnih turbinah se je le težko popolnoma izogniti, mogoče pa jo je omejiti na ekonomsko sprejemljivo raven s pravilno zasnovo turbinskih komponent ter z uporabo visokokakovostnih nerjavnih jekel ali zaščitnih prevlek. Jamičenje zaradi kavitacije v nekaterih primerih spremljajo tudi korozijske poškodbe. V objavljeni literaturi je mogoče najti poročila o raziskavah vedenja prevlek za zaščito pred kavitacijo v okoljih, ki so obremenjena z zmesjo žveplove kisline ter raznih nečistoč, kot so kloridi, ki delujejo kot oksidanti ali reducenti. Komponente turbin zahtevajo kombinirano zaščito pred kavitacijo in korozijo, zato so avtorji tega članka izvedli eksperimente za karakterizacijo odpornosti analiziranih zaščitnih prevlek proti obema pojavomaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo