2.2. Microstructure characterization
After laser cladding treatment, single track specimens were sectioned
in the transverse direction, and then transverse sections
were ground with emery paper and polished. The phases of coatings
were identified by a Shimadzu XRD-7000 X-ray diffraction
with Cu Ka radiation at 40 kV and 300 mA (Cross-sections of the
coatings were irradiated by X-ray beam). Specimens for SEM observations
were chemically etched using an etchant of
HNO3:HF:H2O = 3 ml:2 ml:95 ml. The microstructures of the coating
were examined using a HITACHI S-3400 scanning electron
microscope equipped (SEM). In order to further identify the phase
constituents of the coatings, an electron probe microprobe analyzer
(EPMA, JXA-8100) was used to analyze the composition.