Method for preparing sintered anode aluminum foil and sintered anode aluminum foil

A method for preparing sintered anode aluminum foil, characterized by using ultrasound to alter a stacking structure of aluminum powder on a surface of the anode aluminum foil, resulting in a gradient distribution of aluminum powder particles with different sizes in a thickness of a aluminum powder layer;

• from bottom to top, an average particle size gradually decreases, with larger gaps in lower layers and denser and larger surface area in an upper surface layer;
• the method includes the following steps:
• aluminum powder paste is coated on the surface of aluminum foil, and after ultrasonic treatment, the average particle size of aluminum powder layer structure on the surface of anode aluminum foil gradually decreases from bottom to top particles form large pores in the lower layer, while particles and incomplete shell-shaped particles form a dense surface layer with increased surface area in the upper layer;
• after vacuum drying and sintering, a porous structure consisting of aluminum powder layers with hollow structures is formed to increase the specific surface area and surface layer density, thereby improving specific capacitance and withstand voltage;
• the aluminum powder is spherical aluminum powder prepared by gas atomization method, with a particle diameter ranging from 1 to 10 μm following a normal distribution;
• wherein the method further comprises:
• Step (1):
• dissolving a binder in an organic solvent and stirring to mix evenly, preparing a solution with a certain viscosity;
• Step (2):
• uniformly mixing spherical aluminum powder with a pore-forming agent, brazing powder, and valve metal powder through grinding;
• Step (3):
• adding the spherical aluminum mixed powder obtained in step (2) to the solution prepared in step (1), stirring to mix evenly, to obtain aluminum powder paste;
• Step (4):
• coating the aluminum powder paste obtained in step (3) onto pretreated aluminum foil;
• Step (5):
• subjecting the aluminum foil coated with aluminum powder in step (4) to ultrasonic vibration to improve the stacking state of aluminum powder;
• Step (6):
• vacuum drying the coated aluminum foil obtained in step (5) to obtain dried aluminum foil coated with aluminum powder;
• Step (7):
• sintering the dried aluminum foil obtained in step (6) in an inert atmosphere, and cooling to obtain a composite sintered foil;
• Step (8):
• the composite sintered foil obtained in step 7 is anodized to obtain the sintered anode aluminum foil.