Composite polymer structure having an aluminum polymer anchoring layer, and etching method

A steel-polymer composite structure having an aluminum polymer anchoring layer, wherein the composite structure consists of

• a first substructure consisting solely of steel,
• a second substructure consisting solely of aluminum or an aluminum alloy and adjoining at least partial regions of the first substructure and is applied thereto and
• a third substructure consisting solely of a polymer or polymer fiber composite or polymer particle composite, at least adjoining partial regions of the second substructure and applied thereto
• wherein
• a layered structure of first, second and third substructures extending from the center of the first substructure at least in one direction is formed, so that the first substructure of steel is at least partially covered by and/or bonded to the second substructure of aluminum or an aluminum alloy, and the second substructure is at least partially covered by and/or bonded to the third sub-structure,
• wherein
• the thickness of the first substructure is greater than and/or equal to that of the second sub-structure,
• an anchoring layer directly connects the second and third substructures to one another, the anchoring layer having anchoring structures with undercuts and/or enclosed islands of aluminum or aluminum alloy which are surrounded and/or enclosed and/or filled by material of the third substructure which is still in the liquid state during production, and
• the islands and/or undercuts which are surrounded and/or enclosed and/or filled have
• a cuboidal and/or nested cuboidal shape and
• a minimum size of 200 nm
• and
• sharp and/or rounded edges.