Study of pack cementation aluminising at 630°C on Ni-Fe-Cr-Al alloy sheet produced by EB-PVD

This paper reports the Ni-based alloy sheets which were produced by electron-beam physical vapour deposition and further aluminisation. The microstructures of the as-deposited and aluminised sheets were characterised by scanning electron microscope, X-ray diffraction, and so on. It is found that the as-deposited Ni-base alloy sheets present a Ni-based solid solution structure, and the microcrystal grain was compact, uniform and no precipitation. When the alloy sheets have been aluminised at 630°C, the phase structure changed from Al₃Ni to Al₃Ni₂ during heat treatment period. The thickness of every layer was no more than 10 ?m. The coating was compact and a small amount of aluminium-rich region appeared in a small area. The interface between coating and substrate was clear and smooth, and macro-defect-free.