| Abstract | U ovom radu opisan je postupak nanošenja sol-gel prevlaka TiO₂-ZrO₂ na podlogu od nehrđajućeg čelika X5 CrNi 18-10, postupkom uranjanja. Prije nanošenja prevlake uzorci čelika su očišćeni, brušeni i zatim polirani dijamantnom pastom. Nakon priprave sola, proveden je postupak uranjanja i izranjanja. Oba uzorka su uranjanji i izranjanji brzinom 100 mm/min i držani u soli 3 minute kako bi prevlaka bolje prionula na podlogu. Poslije svakog od 3 ponovljena postupka uranjanja, držanja i izranjanja, uzorci su sušeni na zraku u trajanju od 30 minuta te su nakon toga sušeni u sušioniku na temperaturi od 100°C u trajanju od 1h. Ovaj postupak je proveden 3 puta radi povećanja debljine sloja. Uzorak 1 kalciniran je nakon svakog postupka uranjanja i sušenja (ukupno tri puta). Uzorak 2 kalciniran je samo jednom na kraju čitavog postupka uranjanja. Oba uzorka su kalcinirani na temperaturi od 500°C, dok je temperatura ugrijavanja bila postupna i iznosila je 2°C/min.
Nakon nanošenja sol-gel prevlake ispitivana je prionjivost prevlake Rockwellovom metodom. Uzorcima je ispitana otpornost na erozijsko trošenje. Ispitivanjima je utvrđeno kako povećanje broja udaraca, promjena kuta udara, i promjena abraziva utječe na promjenu otpornosti na erozijsko trošenje. Otpornost na erozijsko trošenje ispitana je kvarcnim pijeskom SiO2 i čeličnom sačmom promjera 700 µm, pri kutevima udara 30° i 90°, i pri različitom broju udaraca (200, 500, 1000). Tragovi trošenja analizirani su nakon erozijskog trošenja pretražnim elektronskim mikroskopom (SEM). Rezultati su pokazali da nepravilni oblik zrnaca kvarcnog pijeska više troše sol-gel prevlaku nego sačma. Također se vidi da povećanjem kuta udara dolazi do većeg razaranja površine prevlake. |
| Abstract (english) | In this study the deposition of TiO2-ZrO2 nanostructured, thin, ceramic coatings on steel grade X5 CrNi 18-10, by dip-coating technique are described. Before the deposition of films, steel substrates and gel-solutions were prepared, the steel surfaces were mechanically ground and then polished with diamond paste. After preparation of sol, depositing of coatings by dip-coating techniques was made, both samples were coating with rate of 100 mm/min, and were kept in salt for 3 minute in order to allow better adhesion to the substrate. After dip-coating, the steel substrates were dried at room temperature for a 30 minutes, after that each steel substrates was dried at 100°C for an hour. The dipping process was repeated three times to increase the film thickness. Sample 1 is calcined after each dip-coating and drying procedure (three times). Sample 2 was calcined only once at the end of the whole process of dip coating and drying. Both samples were calcined at the temperature of 500°C, while the temperature of warming was gradual an it was 2°C/min. After the deposition of TiO2-ZrO₂ coatings, the adhesion was examined with Rockwells method. After that, erosion wear of TiO₂-ZrO₂ ceramic coating is studied. Studies showed that the increase in the number of impact, change the angle of impact, and the change of abrasives effects of altering resistance to erosive wear. Therefore, erosive wear behaviour of TiO₂-ZrO₂ coating was investigated using SiC and steel erodent particle of nominal 700 µm diameters as erodents, at impact angles 30° and 90°, and different number of impact (200, 500, 1000). Scanning electron microscopy (SEM) was used to analyze the eroded surfaces in order to determine erosion mechanisms. The results showed that irregular, angular SiC particles cause more damage than steel erodent particle, also, increasing the angle of impact lead to greater destruction of the surface coating. |
