No abstract

Electrodeposition process of Fe-Ni coating belongs to abnormal co-deposition according to Brenner’s classification, in which Ni is mainly affected by activation, and Fe is mainly affected by diffusion. In this paper, Fe-Ni coating was prepared by laser-assisted electrodeposition technology. The regulation of Fe and Ni contents and coating properties is achieved by using the influence of laser thermal and force effects on the abnormal co-deposition process. The results show that the laser positively shifts the reduction potential and increases the current density. At the laser single-pulse energy is 15 μJ and the laser scanning speed 3000 mm/s, the Fe content of the coating is the lowest, and the Ni content is the highest, which refines the average grain size and reduces surface roughness. Under these parameters, the coating has a small corrosion current density of 5.8×10-7 A/cm2 and a large impedance of 4.3×104 Ω·cm2, its coercivity increases by 0.7 Oe, and its saturation magnetic induction intensity declines by 4.7 emu/g. Compared with the electrodeposited Fe-Ni coating, the corrosion resistance is improved, and the soft magnetic properties is slightly weakened.

No abstract

Ni−Co−W is an alloy with excellent overall performance and wide application prospects. Electrochemical deposition of Ni−Co−W alloys is currently the most promising process for replacing hexavalent chromium plating. Variations in the W content of the Ni−Co−W coating significantly affect its surface morphology, internal structure, and mechanical properties. Considering the numerous defects with conventional electrochemical deposition, a laser was introduced to enhance the quality and rate of deposition. Using a multienergy composite field, the deposition technique enhanced various properties at room temperature. Ni−Co−W alloy coatings were fabricated through electrochemical deposition and laser electrochemical deposition using electrolytes containing Na 2 WO 4 •2H 2 O at concentrations of 12, 15, 18, and 24 g/L in this investigation. This study aimed to examine how laser irradiation strengthens the corrosion resistance of the coatings. The corrosion resistance could be enhanced with an initial W content increase, but the corrosion resistance did not depend entirely on the W content. Variations in the W content of the electrochemically deposited coatings affected the surface morphology, residual internal stresses, and crystal structure, changing the corrosion resistance. In contrast, the laser electrochemical deposition coating was caused by the combined effect of the W content and laser irradiation (concentration of <18 g/L). Laser electrochemical deposition of the Ni−Co−W coating resulted in a higher W content than electrochemical deposition (≥3.5%), improved the residual internal stresses, and refined the grain size of the coating, resulting in better corrosion resistance (corrosion rate decreased by 74% and R ct increased by 109.1% at most).

No abstract