Study On Anticorrosion Property Of Laser Cladding Cu-based Alloy Coating

In order to solve the problem of steel's susceptibility to corrosion and defacement in the marine environment,laser cladding technology has broad application prospect as a new surface modification technology with high power and fast cooling.In this paper,three kinds of Cu-based alloy coatings(1#,2#and 3#)were successfully prepared by high-power semiconductor laser cladding technology on Q235 steel substrate:1#and 2#alloy coatings with C22 bottom layer(about 1400?m)and without bottom layer(about 6000 ?m);and 3#alloy coatings without bottom layer(about 6000 ?m).The phase composition and microstructure of the coatings were analyzed by X-ray Diffraction(XRD),Scanning Electron Microscopy(SEM)and Energy Dispersive Spectrometer(EDS).The micro-hardness of the coatings were investigated by micro-Vickers hardness tester.The corrosion behavior of the cladding layer in seawater was measured by electrochemical testing.The copper ion exudation rates of 2#alloy coating and cast silicon brass(ZCu,contrast sample)in simulated seawater solution were measured and calculated to evaluate the antifouling performance.Three kinds of Cu-based alloy coatings metallurgically bonded to the substrate,and the main phase is the Cu-based solid solution.1#and 2#alloy coatings contain the Ni-based solid solution with Cr,Mo and other elements,and the microstructure is composed of Cu-rich base and the hard precipitation phase rich in Cr and Mo;3#alloy coating is made up of homogeneous Cu-based solid solution.The dilution effect of Fe on 1#and 3#alloy coatings can be avoided effectively,while for 2#alloy coating,the surface of coating with bottom layer contains a small amount of Fe,and the surface of coating without bottom layer contains a high content of Fe.The corrosion resistance of three kinds of copper alloy cladding layer samples in 3.5wt.%NaCl solution is better than that of ZCu;The corrosion resistance of 1#and 2#with stable passivation area is better than that of 3#and ZCu without stable passivation area,besides 1#is superior to 2#and 3#is superior to ZCu.During the test period of 31 days,the exudation rate of copper ions in 2#alloy coating is gradually rising,and after the 24th day of soaking,it is theoretically effective to inhibit the growth of all marine organisms.