Ketahanan Oksidasi dan Korosi Temperatur Tinggi Lapisan FeCrAITiY-MoSi2

Abstract

The research has been carried out on the coating of low carbon steel and its characterization. The coating was set up by two different methods, namely the fire flame spray technique and the Spark Plasma Sintering (SPS) technique. The goal of this research it determination of the optimum coating method. The substrate used was 3. 0 mm thick Stainless Steel ST 41 (low Carbon) with the area of 1.0x 1.0 cm2. In initial stage, it was ultrasonically cleaned in methanol and sand-blasted prior to coating process. There were four kinds of MoSi2 concentration differences in the composition of FeCrAlTiY coatings - x MoSi2, (x = 10, 20, 30 in wt%) sprayed on ST41 steel substrates using the flame spraying technique. High temperature oxidation resistance was carried out at 700°C for 8 cycles. The phaseoccurrence and microstrucrure of the coating before and afterwards the oxidation testing were analyzed using XRD and SEM, Based on XRay diffraction results, the composition of the coating layer consists of phases Fe2O3,, Fe3O4, Al2FeO4, SiO2 and Al2O3, After oxidation testing at high temperatures, it was found that low carbon steel produced a thick Fe-oxide layer and there were cracks on the surface of low carbon steel. Low carbon steels that have been coated with FeCrATiY - M0Si2 produced a Fe2O3 coating that effectively increased the oxidation resistance at high temperatures. In following of the results, it was found that the results of coating using FeCrAITiY - 10% MoSi2 had the lowest mass gain at a temperature of 700°C for 8 cycles. When the SPS tecnique was applied, a layer of FeCrAlTiY-10% MoSi2 was prepared on low carbon sceel. The resistance against oxidation and corrosion was studied in the air and atmosphere containing 20% of the mass of NaCl at 700°C for 8 cycles. The results showed that the solid coating layer was composed by phases (Fe, Cr) and MoSi2 after high-temperature oxidation testing. It was found that a thin protective layer of Al2O3, has beenformed, whilst for oxide compounds consisting of (Cr, Fe) 2O3, Al2O3, and Fe3O4 the layer formed after high-temperature corrosion testing. However, the affected areas after the corrosion testing were worse than after exposure to 8 cycles. This due to the chlorin ion effect and oxide spallation during the cyclic corrasion test.