LI Bin ,LIU Zongde
(Key Laboratory of Condition Monitoring and Control for Power Plant Equipment (North China Electric Power University), Ministry of Education, Beijing 102206)
Abstract: Molybdenum carbide coatings were in-situ synthesized on steel substrate #45 by electro-thermal explosion ultra-high speed spraying process. Phase composition, microstructure and microhardness of the coatings were detected by X -ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS) and micro-hardness tester.The results show that molybdenum carbide coatings are characterized by compact microstructure, low porosity and no lamellar structure. And the metallurgical bonding formed between the coatings and the substrate. The XRD spectra on the coating surface show that the phases consist of molybdenum and molybdenum carbides, such as Mo2C and MoC, oxidation does not occur during the spray process. The high microhardness of the coating can mainly be attributed to carbides in-situ synthesized in the coatings.
Keywords: electro -thermal explosion ultra -high speed spraying process, molybdenum carbide ceramics, microstructure,microhardness