AIP multi-layer coating on DZ125 superalloy substrate

Abstract

The deposited-diffusion multi-layer coating (NiCrAlYSi + AlYSi) on top of DZ125 superalloy substrate with the thickness of 60 μm was fabricated by arc ion plating (AIP). The morphology and phase structure of the coating were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD), respectively. It was found that a lot of β-NiAl phases were formed on the outer layer of the coating. The content of Al element contained in the coating was gradually decreased from the outer layer to the inner layer, and a multi-layer coating with a concentration gradient was formed. This phenomenon was good for forming a dense Al2O3 scale on the surface of the coating at high temperature and further improving the self-healing ability of the scale. The oxidation behavior and hot corrosion performance of the coating samples were tested at the temperature of 1150 ℃ and 900 ℃, respectively. The experimental results show that the oxidation-resistant performance of the superalloy substrate is obviously improved in combination of multi-layer coating. Meanwhile, the service temperature and lifetime of the substrate have been effectively improved.

Keywords

• arc-ion plating
• nicralysi + alysi multi-layer coatings
• high temperature oxidation
• hot corrosion