Abstract: A chemical surface treatment method of a metal improves bonding of different materials in which first pores are formed in the surface of the metal and second pores are formed locally in the surfaces of the first pores by appropriately setting the number of repetitions of alkali treatment and acid treatment, the concentrations of treatment solutions, and treatment temperatures and times using the treatment solutions. The method includes performing the alkali treatment by immersing the metal in a base solution, so as to form first pores in a surface of the metal. The method further includes performing the acid treatment by immersing an alkali-treated result product in an acid solution, so as to form second pores locally in surfaces of the first pores.

Abstract: A method for manufacturing a sandwich panel for a vehicle includes: etching a sheet, which etches one surface of a metal sheet; pressing the sheet, which forms a pattern of a specific shape on the one surface of the metal sheet; laminating a pair of the metal sheets; and performing injection-molding by injecting a plastic resin into the laminated pair of the metal sheets. The method may improve the bonding performance of the sandwich panel, thereby improving the degree of freedom of shape due to the press-molding.

Abstract: A method for manufacturing a sandwich panel for a vehicle includes: etching a sheet, which etches one surface of a metal sheet; pressing the sheet, which forms a pattern of a specific shape on the one surface of the metal sheet; laminating a pair of the metal sheets; and performing injection-molding by injecting a plastic resin into the laminated pair of the metal sheets. The method may improve the bonding performance of the sandwich panel, thereby improving the degree of freedom of shape due to the press-molding.

Abstract: Disclosed is a metal alloy-and-ceramic resin composite. The metal alloy-and-ceramic resin composite includes: a metal alloy, in which recess and protrusion undercuts are formed to provide an average surface roughness of 80 ?m to 150 ?m by degreasing a surface thereof using a surfactant, and etching the degreased surface using an aqueous solution of at least one acid selected from hydrochloric acid, sulfuric acid, nitric acid, and formic acid; and a ceramic resin including 30 wt % to 70 wt % of at least one resin selected from polypropylene, polyamide, polyphenylene sulfide, polyacetylene, polycarbonate, polyester, and polyphenylene oxide, 20 wt % to 60 wt % of silicon carbide, 5 wt % to 7 wt % of inorganic filler, and 3 wt % to 5 wt % of a dispersing agent. The ceramic resin is integrated on the surface of the metal alloy which is formed with the recess and protrusion undercuts, through injection molding.