Abstract
Aim of the study: This research studied the sliding wear resistance of the alloy (AISI 1020) after coating it with a thermal spraying process (NiAlCrSi) as a high-temperature binder, in addition to coating it with a thermal barrier consisting of aluminum oxide and magnesium oxide (Al2O3+MgO). With different weight concentrations of coating powders at the same temperature. With fixed time periods for both coatings. And make a comparison of the wear between the uncoated alloy and the coated alloy.
Methods: A spray welding torch model (QH-2/H) was used to obtain ceramic coats. Sliding wear resistance was also conducted by a pin-on-disc arrangement device, which is designed as per ASTM D5963 specifications under the application of different vertical loads. SEM and XRD were used to analyze the coating's microstructure and phase composition.
Results: The microstructure composition revealed the presence of several residues and primary phases, including Al2O3, Cr2O3, and CrNiO4, which are formed during the coating process, as well as secondary phases traceable back to nickel or chromium phases, in addition to other oxides such as CrMgO4. The morphological data further demonstrate that the coating was extremely heterogeneous, with a high oxide concentration, holes, and microfractures. Comparing the sliding wear results of different coated alloys with the base alloy revealed that there is a gradual increase in the wear rate of all tested samples with increasing loads applied to them. It was also found that the alloy (A4), which contains a large percentage of Al2O3, showed the lowest wear rate compared to the uncoated and coated base alloys. The wear rate of this alloy decreased by 64% under load (10 N) compared to the base alloy, while the coated sample (A3) showed higher wear rates than the uncoated base alloy, with an improvement percentage of 6%.
Conclusions: Using the thermal spray method to paint alloys is economically feasible, in addition to saving time during coating, which does not exceed half a minute, and producing coatings with good mechanical resistance.