Microstructure and corrosion resistance of in-suit coating on copper alloy using laser shock melt injection of fine-CeO2 particles

In order to improve the marine corrosion resistance of the copper alloy, the method of synergistic modification was introduced to prepare the in situ coating on the surface of HSn62-1 by laser shock melt injection of fine-CeO _2 particles. The micrograph and microstructure of the Hsn62-1, in situ coating, and the laser-treated sample were investigated in contrast. Besides, the electrochemical corrosion resistance of the three specimens in 3.5% NaCl solution was studied. The results demonstrated that the in situ coating had good compactness and no apparent defects. The upper part of the in-suit coating was mainly cellular solidification microstructure, while the microstructure in the middle and lower part was coarse dendrite. Compared with Hsn62-1 copper alloy, the corrosion resistance of the laser-treated sample and the in-suit coating were improved, which proved that the synergistic modification of laser and rare earth could improve the corrosion resistance of the copper alloy. The analysis indicated that the rare earth elements in the in-suit coating would undergo hydrolysis reaction to form the dense rare-earth hydroxide in an ‘island growth’ way, which effectively prevented the invasion of corrosion ions.