Microstructure and Performance of Typical Anti-Cavitation Coatings Prepared by Thermal and Cold Spraying
Cold spraying,as a newly emerging coatings metal deposition technology,has many advantages,such as high bonding strength,high hardness,and low oxide inclu-sions,thus exhibiting significant application potential in protective coatings of overcurrent devices for cavitation dam-age.In this study,highly dense CuAl9Fe1 aluminum bronze coatings were deposited on the surface of the 40Cr steel substrate by cold spraying.Using techniques such as optical microscope,scanning electron microscope,microhardness indenter,supersonic cavitation tester,and 3D profilometer,the coating microstructure,mechanical properties and cavitation performances were systematically studied,and the coating cavitation morphologies and cavitation mechanisms were analyzed.The cold sprayed CuAl9Fe1 coatings were also compared with HVOF sprayed typical WC type anti-cavitation coatings(WC-Co-Cr and WC-Cr2 C3-Ni).The results show that the average porosity of cold sprayed CuAl9Fe1 coating is 1.4%,the average micro-hardness is 3126 MPa,the average bonding strength is 32.3 MPa,and the depth of erosion after 6 h cavitation is 4.988 μm;as a comparison,the average porosities of HVOF sprayed WC-Co-Cr and WC-Cr2 C3-Ni coatings are 0.7%and 1.6%,the average micro-hardnesses are 10 065 and 10 094 MPa,the average bonding strengths are 84.2 and 73.5 MPa,and the depth of erosion are 11.901 and 10.645 μm,respectively.Although the cold sprayed CuAl9Fe1 coat-ing has lower hardness,its higher plasticity and toughness can effectively suppress the initiation and propagation of cracks at interparticle boundaries during cavitation and particle detachment,therefore,it has better cavitation resistance than WC type coatings prepared by HVOF.
cold sprayingaluminum bronze coatingHVOFWC based coatingscavitation resistance
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