Abstract:
In order to improve the wear resistance of ferrite/Martensite steel in liquid lead bismuth environment, Al
2O
3 and Al
2O
3/FeCrNi coatings were successfully prepared on a typical ferritic/Martensitic steel by pulsed laser cladding, and the phase constitutions, compositions, microstructural characteristics and hardness of both the coatings were characterized and analyzed by jointly using X-ray diffraction, electron channeling contrast imaging, energy dispersive spectroscopy, electron backscatter diffraction and Vickers indenter. The results show that cladding zone (CZ) of the Al
2O
3 and the Al
2O
3/FeCrNi coatings are about 260 μm and 180 μm in depth, respectively. The part of the CZ near the Al
2O
3 coating surface is mainly consisting of bulk δ ferrite, while the part far away from the surface consists of martensitic plates. The CZ of Al
2O
3/FeCrNi coating has more uniform microstructures mainly comprised of martensitic plates. Hardnesses of the Al
2O
3 and the Al
2O
3/FeCrNi coatings are (363±75) HV and (467±17) HV, respectively, both of which are significantly higher than that of the substrate ((267±5) HV). Comprehensive analyses suggest that the higher hardness of Al
2O
3/FeCrNi coating can be attributed to grain refinement and second phase strengthening.