Ultrasonic-assisted electrodeposition of copper coatings on gadolinium regenerator fins: Bubble detachment and performance enhancement

The metal gadolinium (Gd) has significant potential applications in refrigeration technology due to its remarkable magnetocaloric effect. However, Gd has extremely active chemical properties and is highly prone to corrosion when working in heat exchange medium. To enhance the corrosion resistance of Gd in heat-exchange media, we employed ultrasonic-assisted electrodeposition to prepare a copper coating on the surface of Gd. The influence of ultrasonic waves on the cathode surface was observed, and the effects of different ultrasonic power levels on the micromorphology and properties of the copper coatings were analyzed. The results revealed that ultrasonic treatment refined the grains and exhibited a distinct (111) crystal orientation. Furthermore, ultrasound can effectively improve the surface quality of the coating, forming a uniform and dense surface. With the increase in ultrasonic power, the surface roughness of the coating initially decreased and then increased. Additionally, ultrasonic treatment enhanced the coating thickness and surface hydrophobicity, and the surface corrosion resistance was improved by 76.8% compared to when no ultrasonic treatment was used. Further comparison of the element content and binding force at 0 W and the optimal power of 180 W revealed that the copper content increased from 77.8% at 0 W to 92.4% at 180 W, and the binding force increased from 2.19 N at 0 W to 4.86 N at 180 W. Overall, the preparation of a copper coating on the surface of Gd metal using ultrasonic-assisted deposition technology can significantly enhance its service life in magnetic refrigeration regenerators.