Volume 47, Issue 10

In this study, Co-Cr-Mo powder was coated on the surface of AISI 304 stainless steel by the plasma transfer arc (PTA) process at 80, 90 and 100 A current values and argon gas was used for both plasma and protective. Deposition layers were examined with optical microscopy, SEM, EDX, XRD analysis and microhardness test. The thickness of the coating increased with current density. No cracks or pores were detected in the interface and coating layer. Higher current levels resulted in higher dilution levels and also in melting/burning of the substrate.

In this study, ZrO2 + Y2O3/Al 2 O 3 powders were coated on the surface of aluminum bronze (Cu + 5 % Al) by using the atmospheric plasma spraying method. The effect of Al 2 O 3 on microstructure and hardness was examined in four different coatings applied by using 5-10-20 % Al 2 O 3 ratio in ZrO2 + Y2O3 and ZrO2 + Y2O3. For this purpose, microstructure images of the coated layers were taken in optical microscope and SEM, EDX and XRD analyses were performed and their microhardness values were measured. It was observed that a porous structure occurred in the coatings containing ZrO2 + Y2O3/Al 2 O 3 . The coatings containing Al 2 O 3 showed higher microhardness values than the one without Al 2 O 3 , and depending on the increase of Al 2 O 3 amount, the amount of porosity increased and microhardness value decreased.